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1. fied replica of the input signal with the weighting set to FLAT or of the weighted or filtered signal otherwise The rms value of the output open circuit voltage correspond ing to a full scale indication on the meter is 0 5 volts The source impedance is 600 ohms and any load can be connected without affecting the meter reading or linear operation of the output circuits 2 6 METER OUT DC JACK This jack is intended primarily to provide a detected DC signal linear in decibels for driving a DC recorder The recorder can be used to display the Fast Slow Impulse or Peak sound level as a function of time or octave band pressure levels as a function of frequency Details of con nection and use of a DC recorder are given in section 2 19 The DC signal available at the METER OUT DC jack can also be used to drive a meter to provide a wide dynamic range display or to trigger an alarm The signal at this jack is 4 5 V behind a resistance of 4 5 corresponding to full scale on the meter Each 0 1 volt change in open circuit voltage corresponds to a 1 dB change in level i e the sensitivity is 0 1 V dB The useable range in open circuit output voltage is 6 5 volts to 0 5 volts or a linear decibel range of 60 dB Any load resistance can be connected If the output is short circuited it produces current of 1 ma at full scale on the meter Figure 2 4 shows the sine wave frequency response of the 1933
2. 55 C50 Cap Ceramic 10 pF 10 500 4404 0108 72982 831 10 pF 10 C51 Cap Ceramic 82 pF 10 500 V 4404 0828 72982 831 82 pF 10 C52 Cap Tant 4 7 uF 20 10 V 4450 4700 56289 150D465X0015B2 CHOKES Li thru L3 Shielded 56 uH 10 4300 6390 99800 3500 56 10 L4 Shielded 18 000 pH 10 4300 6704 99800 3500 18 000 uH 10 DIODES CR1 thru CR10 Type 1N4009 6082 1012 24446 134009 thru CR22 Type 1N995 6082 1002 80368 1N995 CR24 and CR25 Type 1N4009 6082 1012 24446 1N4009 CR27 thru CR30 Type iN455 6082 1010 07910 13455 8 4 6083 1097 12498 70333627 VR2 Type 1N746 3 3 V 6083 1005 07910 1N746 INTEGRATED CIRCUITS UI Program Amp Atten Hybrid 1933 0840 24655 1933 0840 U2 Linear Type LM 101A 5432 1020 12040 LM 191A U3 thru 05 Linear 2911 5432 1031 12040 2911 06 U7 Peak Detector Amplifier Hybrid 1933 0830 24655 1933 0830 U8 thru 011 Linear Type LM 308H 5432 1030 12040 LM 308H 012 Digital Type CD4011E 5431 7000 79089 CD4011AE U13 Digital Type CD4017E 5431 7001 79089 CD4017AE 014 Program Hybrid 1933 0840 24655 1933 0840 015 4 Channel MOS Switch 551 5434 0109 42498 551 U16 Linear Type LM 301A 5432 1004 12040 LM301A Fed Stock No 5910 813 8160 5910 974 5699 5910 974 5697 5910 974 5697 5910 813 8160 5910 974 5697 5910 083 6445 5910 974 5697 5910 752 4185 5910 813 8160 5910 813 8160 5950 410 387
3. INPUT FROM DIFFERENT SUSASSENM gt a YPUT REMAINS Oh BURASDE MRL gt INPUT FAOM SANE v BUFF JOUT 475 AT36 19 0 PEAK DET AMP US Ree PEAK OR PEAK PET SECTORS THAV U9 BUFF OUT PEAK DET AMP U7 z c44 9 A38 2 095 OVERLOAD COMPARATOR 2 ON LAMP ON 45 Aqa BASE DIAGRAMS BOTTOM VIEWS c INTEGRATED CIRCUITS nsa NP o TRANSISTORS S o o c 9 o 5 5 2 2 2 ole conn 8 ATIG 2 g ues s e gt 2 9 7 Q 5 4 5 7 6 4 13 2 vie 013 NOTES lt CIRCUIT ALL COMPONENTS WITHOUT PREFIX LETTER ARE ON MAIN P C BOARD SIDE COMPONENTS WITH PREFIX ARE ON MAIN FRAME PREFIX E ARE MANUAL y T ETCHED CABLE OVERRIDE a Figure 5 7 Schematic diqgram for 1 ital circuits Parts amp Diag 5 5 0 2 21 0579 15 7 201109 gx 7 poy ASMP 1073 22 5 SLNINOIWO2 2 777 3774 77 lt e MJ o gt 5 2 2 lt L 2 0 4 1 Q gt 3 e 3 0s KO E
4. 2 5 7 40 1520 20 50 100 perpendicular incidence response and tolerance 4 ARS 227 it 555 j 5 RESPONSE dB i d 180 500 700 2 5 7 Ware 50 TO 00 200 4 FREQUENCY Hz ia Correction to be added algebraically to perpendicular incidence response Typical directional response of the microphone to find random and grazing incidence free field response Figure 3 2 Characteristics for 1 in electret microphone flat perpendicular incidence response 3 2 THEORY RESPONSE dB i FREQUENCY Hz Typical random incidence response and tolerance V SUP T CO wee ANN SESH RS NN A 2 5 270 RESPONSE 48 ampETSHEEXS 7555 500 700 kHz 2 5 7 20 50 70 100kM 200kHz FREQUENCY Hz ENT Correction to be added algebraically to random incidence response Typical directional response of the microphone to find perpendicular and grazing incidence free field response Figure 3 3 Characteristics for electret microphone flat random incidence response PERPENDICULAR INCIDENCE RESPONSE i 20 50 70 100 200 500 700 kHz 2 5 10 15 20 30kHz FREQUENCY Hz RESPONSE d8 Typical perpendicular incidence response and tolerance RESPONSE dB 1 7 00 00 700
5. 59 3 hs RIS ese 7 96K 5 lt 2a rs pes 5 6 3 f v SWITCHED FROM 2 51 8 6 MPL FROM MAIN BD 726 9 WAVEFORM CONDITIONS IKH2 O 5Vrms 348 0 355v 77 AT INPUT AT17 WEIGHTING FLAT PEAK MODE 70 J 422 51 SECTION 54 7 lt gt OUTPUT LOAVES HEAVY LINE INDICATES PRINTED CABLE OUTPU HIM AVR ON VIEW IMPULSE CONNECTION 5 Figure 5 12 Schematic diagram for 1933 detector and meter output circuits PARTS amp DIAGRAMS 5 13 Figure 5 11 Etched circuit board assembly P N 1933 4710 GR 1940 POWER SUPPLY and CHARGER SPECIFICATIONS Power Source 5 V for line operation of 1933 6 5 V for line opera of 1935 250 mA Charging Source 200 mA max for charging batteries in 1933 or 1935 automatically reduces to 30 mA trickle charge bat teries are charged Charging time 16 h Supplied 5 rechargeable nickel cadmium C cells to replace chargeable batteries in 1933 or 1935 Power 100 to 125 or 200 to 250 V 50 to 400 Hz 11 W Mechanical DIMENSIONS wxhxd 4 38x4 25x9 44 in 111x108x240 mm WEIGHT 3 5 Ib 15 ka net 5 Ib 2 3 shipping INTRODUCTION The 1940 Power Supply and Charger includes two inde oendent sources a power source and a charging source The power s
6. and J2 Adjust the load pot until the voltage reads 5 5 V The current should read 250 275 mA Adjust the load pot fully cw the voltage should drop smoothly to O V and the current remain constant Set the load pot fully ccw the voltage should read 6 4 6 6 V b Connect the load fixture to J1 and J3 Adjust the load pot until the voltage reads 4 0 V The current The voltage should drop smoothly to O V and the current remain constant Set the load pot fully ccw the voltage should read 5 1 5 3 V Line Regulation Check a Connect the load fixture to the terminals indicated on Table 2 Adjust the load pot for 150 mA in each case Adjust the Variac output between 95 and 130 Vac Note the change in voltage at the terminals tested b With the oscilloscope measure the noise at the ter minals for the same conditions listed in table 2 Table 2 LINE REGULATION Connect Load RMS Hum Fixture to Terminal Load Current Regulation Ripple Component NR mA V mV mv 1 J2 150 lt 0 1 lt 10 lt 15 J1 J3 150 lt 0 1 lt 10 1 5 41 J4 150 lt 0 1 lt 50 1 9 J1 J5 150 0 1 50 1 5 Hum Check Measure the RMS voltage of each component with 1900 at the conditions listed in Table 2 Measure 60 120 and 180 Hz WTG 5 7 Figure 4 Etched circuit diagram P N 1940 4700 NOTE Orientation Viewed from foil side Part number Refer to caption Symbolism O
7. 2 5 2 7 USE OF FILTER JACKS 2 6 2 8 CHANGING MICROPHONES x 29 PROXIMITY EFFECTS OF CASE AND OBSERVER 28 2 10 EXTENSION CABLES BY 2 11 USE OF MANUAL OVERRIDE CONTROL amp EOS we 28 2 12 USE OF SOURCE CONTROL 2 8 2 13 DATA OUT CONNECTOR 2 8 2 14 USE WITH ACCELEROMETERS 2 8 2 15 ENVIRONMENTAL EFFECTS s wow wow e s 2 16 INTERNALLY GENERATED NOISE 2 10 2 17 USE OF ACCESSORIES i p x EM 2 18 1940 POWER SUPPLY AND CHARGER cme s 2 19 USING A DC RECORDER x 2 20 USING THE SOUND LEVEL METER AS A PREAMP s 2 1 UP AND CALIBRATION Before making measurements with the 1933 check that the SOURCE control MANUAL OVERRIDE control and MAX MIKE dB control are properly set and that the battery voltage is adequate See 2 12 Use of Source Control 2 11 Use of Manual Override Control 2 8 Chang ing Microphones and 2 4 Checking and Changing the Batteries for procedures Then check calibration using either the internal electrical calibrator or the 1562 Sound Level Calibrator Calibration should be performed with the 1933 stabi lized at the ambient temperature If this ambient tempera ture is outside the range of 10 to 35 C 50 to 95 special calibration procedures are required an internal electrical calibration is performed correct each subsequent sound level readi
8. 60624 Darnell Corp Ltd Downey Calif 90241 Electro Motive Mfg Co Wilmington Conn Nytronics Inc Berkeley Heights N J 07922 Dialight Co Brooklyn N Y 11237 General Instr Corp Newark N J 07104 Drake Mfg Co Chicago III 60656 Hugh H Eby Inc Philadelphia Penn 19144 Elastic Stop Nut Corp Union N J 07083 Erie Technological Products Inc Erie Penn Beckman Inc Fullerton Calif 92634 Amperex Electronics Co Hicksville N Y Carling Electric W Hartford Conn Elco Resistor Co New York N Y JFD Electronics Corp Brooklyn N Y 11219 Heinemann Electric Co Trenton N J Industrial Condenser Corp Chicago Ill 60618 Amphenol Corp Danbury Conn 06810 E F Johnson Co Waseca Minn 56093 IRC Inc Philadelphia Penn 19108 Kulka Electric Corp Mt Vernon N Y Lafayette Industrial Electronics Jamaica N Y Linden and Co Providence Littelfuse Inc Des Plaines Ill 60016 Lord Mfg Co Erie Penn 16512 Mallory Electric Corp Detroit Mich 48204 James Millen Mfg Co Malden Mass 02148 Mueller Electric Co Cleveland Ohio 44114 National Tube Co Pittsburg Penn Oak Mfg Co Crystal Lake Patton MacGuyer Co Providence 1 Pass Sey mour Syracuse N Y Pierce Roberts Rubber Co Trenton N J Positive Lockwasher Co Newark N J American Machine amp Foundry Co Princton Ind 47570 Ray O Vac Co Madison Wisc TRW Electronic Comp Camden N J 08103 General Instruments Corp Brookl
9. 75 DCWV C6 Tantalum 56 uF 10 26 DCWV 4450 5520 56289 C8 Mylar 18 uF 4860 9474 84411 663UW 18 C9 Ceramic 30 pF 4404 0305 72982 831 Cll and C12 Ceramic 01 pF 4401 3100 80131 CC61 01 pF 80 20 5910 974 5697 C15 Ceramic 0 1 80 20 100 DCWV 4403 4100 217 Tantalum 1 LF 4450 4300 CONNECTORS Jack 062 Bd Ec 4260 0850 22526 47330 DIODES CRIO 1N3604 6082 1001 INTEGRATED CIRCUITS U2 Linear LM308 H 5432 1030 12040 LM308H RESISTORS R4 Pot Cermet 10 kQ 6049 0109 80294 R10 Comp 30 2 6099 0305 75042 BTS 30 Q 5 R11 Comp 47 MQ 6099 6475 75042 BTS 47 MQ 5 R15 Film 15 4 M 6350 5154 75042 CEA 15 4 MQ 1 R16 Thermistor 1 27 2 6620 1041 R17 Film 19 6 kQ 6250 2196 R18 Film 47 5 6250 3475 75042 CEA 4 75 1 5905 646 5681 R19 Film 27 4 kQ 6250 2274 R20 Film 10 5 kQ 6250 2105 R21 Film 59 0 kQ 6250 2590 75042 CEA 59 0 1 R22 Comp 10 kQ 6099 3105 75042 BTS 10 5 5905 683 2238 R23 Film 4 49 kQ 6250 1449 75042 CEA 4 49 1 R24 and R25 Film 604 Q 6250 0604 75042 CEA 604 1 R26 Comp 6 8 6099 2685 75042 BTS 6 8 5 5905 686 9997 R27 Pot Cermet 500 6049 0114 80294 R28 Film 383 kQ 6250 3383 75042 CEA 383 kQ 1 R29 and R30 Film 15 4 kQ 6250 2200 75042 CEA 20 0 1 5905 702 5971 R31 Film 22 6 kQ 6250 2226 75042 CEA 22 6 kQ 1 5905 683 5747 R32 Film 2 1 kQ 6250 1332 75042 R33 and R34 Film 19 1 kQ 6250 2191 75042 CEA
10. PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT GenRad 1933 Precision Sound Level Meter and Analyzer User Guide and Service Manual LABS INC 534 Main Street Westbury NY 11590 www ietlabs com manutacturer by TEL 516 334 5959 800 899 8438 FAX 516 334 5988 GenRad IET LABS INC 534 Main Sreet Westbury NY 11590 516 334 5959 800 899 8438 Fax 516 334 5988 http www ietlabs com IET New Products STANDARDS DECADES STROBES Find a Product Technical Applicati Formerly Manufactured By J QuadTech GenRad General Radio Request a Quote X Price List Now being manufactured serviced calibrated Place an Order and fully supported Request Catalog by IET LABS Widest Choice Contact Us COST EFFECTIVE QUALITY WETTER STANDARD OR CUSTOM SOLUTION of Decades R L CeRTDeVOLTAGE If you need products or CURRENT ePROCESS CONTROL service by Genrad esi IET is compliant with ISO 9001 ELIS URSA UTE Product Area of Interest ISO IEC 17025 ANSI 2540 1 1994 and MIL STD 45662A Find a Products Technical Applications Request a Quote Place an Order Free Offer Request a Catalog Contact Us Copyright 1999 2001 IET Labs Inc All rights reserved Problems or Comments Contact webmaster ietlabs com To navigate our easy to use website for quick access to specifications and prices 1 Sel
11. a Repeat the set up and set the controls the same as para 4 6 4 and retain the same connections b Adjust the 1310 Output for O dB as read on the HP 334 A c Refer to Table 4 7 and adjust 1310 to the center fre quency of each octave band as the WEIGHTING BAND Control is switched to each octave band setting Compare the readings of the 334 A for each octave band The levels of the bands should be uniform within 1 dB from 31 5 Hz to 8 kHz and within 2 dB for the 16 kHz band SERVICE 4 7 4 6 6 Internal Calibrator Ad justment Use same setup of Figure 4 1 a Set the controls as follows 1310 Frequency Dial s 2 6 9 s Frequency Range 200 2 1450 Attenuation O dB 1933 Range dB Control 130 dB full scale BAND Control 1 kHz MANUAL OVERRIDE MAX dB Sw AUTO Pushbuttons PLAT w Go 3 IMP SLOW OUT fast SOURCE Sw TAPE b Adjust the 1310 output for a roading of 0 5 V at the SIGNAL OUT AC as read on the 1808 The 1933 meter must now read 130 0 4 dB if not repeat the gain and meter adjustment para 4 6 3 c Set 1933 controls as follows RANGE dB control WEIGHTING BAND control SOURCE Sw Adjust CAL potentiometer E R10 on A board be tween SOURCE switch and MANUAL OVERRIDE MAX dB switch Figure 4 5 for a full scale reading on the 1933 panel meter 100 dB full scale 1 kHz Band CAL 4 6 7 Adjustment
12. k A Re Ulg i 100K 7 8 BLANKING s CLK E 14 lt X CRS i END Lg 7 4 R33 e 19 5 15 3 4 5 cR CR 5 6 343 A32 RA 8 io 2 2M p c47 lask cR 1024 IM R54 44 gt 4 7M TPG MANUAL OVERRIDE 9 ast dB 9 56 2K 9 MILL mE n n BUNK gt 9 CAIG ACTA 9 R30 1 E 2735 RST a c LEVEL CONTROL 9 E SWITCH SETTINGS OF 2 AND 6 65 ARE SHOWN HN TOMAR 9 4 BGS CONTROL SET TO 30 READ amp 8 USINA RED DOT X 11 gt OVLD 9 MSA 3 ats 2 35 gt 48 09 WHEN 6 52 ON MIKE C 5 pig OFF 9 IN ALL OTHER 06 7 90 E RANGE T3 AAs AND ARE anpa LANES 80 Uus a SEY SWITCH NOT VIA CHASSIS LSR LEAST SENSITIVE RANGE NOD OUT MSR MOST SENSITIVE RANGE 9 5 CIRCUIT BOARD SURFACE rcnt pean B CONTACTS FROM STILT amp CREW ABOVE REY 6 01 SECTION SECTION NEAREST PANEL 151 AOTORS COW 7 P UUT LEAVES SUMASSEMML Y i
13. 04713 05170 05624 05748 05820 06743 07126 07127 07261 07263 07387 07595 27828 27829 07910 07983 07999 08730 09213 09408 09823 09922 11236 11599 12040 12498 12672 12697 12954 13327 14433 14655 14674 14936 15116 15238 15605 16037 16636 17771 18736 19396 19048 19617 19644 19701 20754 21335 22753 23342 24446 24454 24455 24655 28520 28959 30646 30874 32001 33173 34141 35929 37942 38443 40931 42190 6 70 FEDERAL MANUFACTURER S CODE From Federal Supply Code for Manufacturers Cataloging Handbooks H4 1 Name to Code and H4 2 Code to Name as supplemented through August 1968 Manufacturer Jones Mfg Co Chicago Illinois Walsco Electronics Corp L A Calif Schweber Electronics Westburg L I N Y Aerovox Corp New Bedford Mass Alden Products Co Brockton Mass Allen Bradley Co Milwaukee Wisc Leeds Radio Company N Y Litton Industries Inc Beverly Hills Calif Texas Instruments Inc Dallas Texas Ferroxcube Corp Saugerties N Y 12477 Fenwal Lab Inc Morton Grove III Amphenol Electron Corp Broadview Fastex Des Plaines IIl 60016 Carter Ink Co Camb Mass 02142 G E Semicon Prod Syracuse N Y 13201 Grayburne Yonkers 10701 Pyrofilm Resistor Co Cedar Knolls N J Clairex Corp New York N Y 10001 Arrow Hart amp Hegeman Hart Conn 06106 Digitronics Corp Albertson N Y 11507 Motorola Phoenix Ariz B5008 Engr d Electronics S
14. 1 8 W 2N3457 D30A3 Figure 5 9 Schematic diagram for 1933 preamplifier TRANSISTOR BASE DIAGRAMS SWITCH MOUNTED IN 833 BATTERY COMPARTMENT NORMALLY CLOSED OPENS WHEN TO 1940 POWER SUPPLY t2vV A BT1 37 LLS ATO LAMP RETURN 7 CR 30 24 TO DET 80 Ca S544 gt 5 CaF b 4 3004 AT 25 TO DET AT I4 gt GND dt 3 9v 22 p DET BD AT 15 m AT 35 TO E S3 t E 2 917 1 VAL AGI 8 Ree 4 34 52 N 418 3 csG R72 47u 620 77 NOTE HEAVY LINE INDICATES PRINTED CABLE CONNECTION Figure 5 10 Schematic diagram for 1933 power supply Parts amp Diag 5 11 A OO0K 4 RI 5 d Qi 71 pr I Wee OOl e 5 L amp ec Cz j eu Bu Fa 23 75 2 JOOK 4 7K OOK TRANSILIS TOP BASE DIAGRAMS 2 s 96 8 a C c 0222 LAB SELECTEO Figure 5 8 Etched circuit board for removable preamplifier assembly P N 1933 4795 ELECTRICAL PARTS LIST Fed Ref Des Description GR PartNo Mfg Code Mfg Part No Fed Stock No Detector Board P N 1933 4710 CAPACITORS C5 Tantalum 0 33 pF 10 75 DCWV 4450 4290 56289 33 UF 10
15. 70 dB full scale WEIGHTING BAND Control WEIGHTING Pushbuttons nou 5 E Output Peak Detector a Set the 1310 output level for a full scale reading on the 1933 panel meter Note the dB reading on the 1808 AC Millivoltmeter i b Slowly increase the output level of the 1310 Oscillator until the overload light just comes on The 1808 AC Milli voltmeter should read 15 0 5 dB greater than the value corresponding to full scale on the 1933 This checks the trigger level of U7 and U9 c Slowly reduce the output level of the 1310 oscillator until the overload light just goes off This value should be 1 1 0 5 dB less than the level at which the overload light just goes on Input Peak Detector For this check remove the preamplifier section from the 1933 mast and connect the input directly using the micro phone mast to 274 connector a Set 1933 RANGE dB Control 130 dB 1450 Attenuation 10 dB Adjust the 1310 output for a full scale reading on the 1933 and then set the 1933 GHTING BAND Control to 31 5 Hz b Slowly increase the output level of the 1310 until the overload light just comes on The 1808 should again read 15 0 5 dB greater than the value corresponding to full scale on the 1933 This checks the trigger level of U6 and U8 Slowly reduce the output level of the 1310 until the overload light just goes off This should again be 1 1 0 5 dB less than the leve
16. 75042 75382 75491 75608 75915 76005 76149 76487 76545 76684 76854 77147 77166 77263 77339 77342 77542 77630 77638 78189 78277 78488 78553 79725 80048 80131 80183 80211 80258 80294 80368 80431 80740 Manufacturer National Co Inc Melrose Mass 02176 Norma Hoffman Stanford Conn 06904 RCA New York N Y 10020 Raytheon Mfg Co Waltham Mass 02154 Sangamo Electric Co Springfield III 62705 Shallcross Mfg Co Selma N C Shure Brothers Inc Evanston Sprague Electric Co N Adams Mass Thomas and Betts Co Elizabeth N J 07207 TRW Inc Accessories Div Cleveland Ohio Torrington Mfg Co Torrington Conn Union Carbide Corp New York 10017 United Carr Fastener Corp Boston Mass Victoreen Instrument Co Inc Cleveland O Ward Leonard Electric Co Mt Vernon N Y Westinghouse Lamp Div Bloomfield N J Weston Instruments Newark N J Atlantic India Rubber Chicago Ili 60607 Amperite Co Union City N J 07087 Belden Mfg Co Chicago 60644 Bronson Homer D Co Beacon Falls Conn Cambridge Thermionic Corp Camb Mass 02138 Canfield H O Co Clifton Forge Va 24422 Bussman McGraw Eidson St Louis Mo ITT Cannon Elec L A Calif 90031 Centralab Inc Milwaukee Wisc 53212 Continental Carbon Co Inc New York N Y Crescent Box Corp E Phila Penn 19134 Coto Coil Co Inc Providence R I Chicago Miniature Lamp Works Chicago Cinch Mfg Co Chicago
17. 892 8700 CR7 and CR8 Type 1N4140 6081 1014 13327 1N4140 CR9 and 10 1N4003 6081 1001 14433 1N4003 CR11 MPD200 6082 1033 06751 200 12 and 13 Type 1N455 6082 1010 07910 1N455 5960 877 8255 VRI 1N750A 6083 1028 07910 1N750A 5960 754 5897 INTEGRATED CIRCUITS Ul and U2 LM301A 5432 1004 12040 LM301A RESISTORS Ri 15 5 1 4 6099 3155 75042 BTS 15 5 5905 681 8818 R2 10 25 1 4 W 6099 3105 75042 BTS 10 kQ 5 5905 683 2238 R3 3 59 1 4 W 6099 2305 75042 BTS 3 t5 5905 682 4097 R4 3 0 9 t5 1 4 W 6100 9305 01121 3 0 9 5 R5 5 1 5 1 4 W 6099 2515 75042 BTS 5 1 59 5905 683 2241 R6 3 5 1 4 W 6099 2305 75042 BTS 3 5 5905 682 4097 R7 1 3 5 1 4 W 6099 2135 75042 BTS 1 3 5 5905 686 3119 R8 6 34 5 1 8 W 6250 1634 75042 CEA 6 34 1 R9 Potentiometer 2 10 6051 2209 07999 2600 2 10 R10 6 65 1 1 8 W 6250 1665 75042 CEA 6 65 1 5905 855 3178 Ril 2 4 0 5 1 4 W 6100 9245 01121 2 4 0 5 R12 5 1 5 1 4 W 6099 2515 75042 BTS 5 1 kQ 59 5905 683 2241 R13 1 5 1 4 W 6099 2105 75042 BTS 1 5 5905 681 6422 R14 8 06 19 1 8 W 6250 1806 75042 8 06 t1 R15 15 4 1 1 8 W 6250 2154 75042 CEA 15 4 1 5905 557 3775 R16 10 5 1 4 W 6099 3105 75042 BTS 10 kQ 5 5905 683 2238 R17 1
18. OUT fast MAX MIKE dB 130 SERVICE 4 15 1562 A Calibrator OFF START FREQUENCY SW 1 kHz Place the 1562 on the microphone with appropriate adaptor ring and adjust the MIKE B CAL potentiometer on back of main circuit board for a 114 dB reading on the 1933 panel meter 4 7 3 Calibration with Microphone a Remove the 1 in microphone with adaptor from the preamplifier assembly and connect the micro phone directly b Set the 1933 SOURCE switch to MIKE A c Place the 1562 at 1 kHz on the microphone with appropriate adaptor ring and adjust MIKE A CAL poten tiometer on back of main circuit board for a 114 dB read ing on the 1933 panel meter 4 16 SERVICE 4 7 4 Calibration When Only Mike is Supplied The following acoustical calibration procedure should be followed when the 1933 is supplied with in micro phone only a he controls remain the same as para 4 7 2 b Connect microphone to the 1933 preamp assembly c Repeat step c in para 4 7 2 d Remove the microphone connect the 10 dB micro phone attenuator supplied to the preamp assembly then remount the microphone e Set the 1933 controls MAX MIKE dB 140 Range dB 120 full scale SOURCE MIKE A Repeat step c in para 4 7 3 Parts Lists and Diagrams Section 5 MECHANICAL PARTS FRONT AND RIGHT SIDES 52 MECHANICAL PARTS LEFT SIDE 5 3 FEDERAL MANUFACTURERS CODE
19. SWITCHES 51 Switch Rotary 52 Rotary TERMINALS EC Test Point TRANSFORMER TRANSISTORS Q2 thru 04 2N4250 05 Type 2N4384 Q6 thru Q13 Type 2N3391A Q14 and Q15 Type 2N3414 Q16 Type 2N5190 Q17 Type 2N4250 018 and Q19 Type 2N3391A 5 6 PARTS amp DIAGRAMS ELECTRICAL PARTS LIST cont GR Part No 7890 5584 7890 5585 7970 2600 1933 2110 8210 1135 8210 1131 8210 1092 8210 1047 8210 1196 8210 1135 8210 1092 Mfg Code 79089 79089 24655 24655 93916 93916 24454 75491 93916 93916 24454 Mfg Part No Fed Stock No SERIES 160 SERIES 160 7970 2600 1933 2110 2N4250 2N4384 2N3391A 2N3414 2N5190 2N4250 2N3391A 3 3 arn CAME v 2 089 V AMS 3 ex D T prem Mer jap gt D PY osx 84 p 5 R 9 deer di rum ML a dd Ba __ 29 a M IRON Di i lt CAL ants 77K ESI Ur E C2 7r 443 SCHEMATIC DIAGRAM ANALOG CIRCUS 7 ib LFS 2257 MOTES Y 70 COMPONENTS LETTERS xRC Ou ANM 74 Au A gt Dl
20. The correct level for each frequency setting of the 1562 Calibrator and for each WEIGHTING or BAND is shown in Table 4 1 The tolerance on the reading is 1 5 dB unless otherwise noted FREQUENCY VS dB LEVEL Level d Weighting 1000 For 1961 9601 Subtract 0 3 dB For 1961 9602 Subtract 1 1 dB 96 96 114 lt 96 96 114 lt 96 SERVICE 4 1 4 3 2 Test With Oscillator and Voltmeter An electrical test can be made on the instrument ex cluding its microphone with an oscillator that covers the frequency range from 5 Hz to 100 kHz and an accurate voltmeter to monitor the output of the oscillator Though this is a more definitive test of filter and weighting network frequency response sensitivity cannot be tested precisely Use a 1560 P9 Dummy Microphone to replace the micro phone The Dummy Microphone simulates the 1 2 in elec tret condenser microphone Connect the oscillator to the Dummy Microphone and set it to 0 5 V at a frequency of 1 Hz Maintain the level at 0 5 V for all of the following and lower left corners of the etched circuit board as viewed from the rear The circuit board will now swing out on its hinges located along the right side of the board Before returning the circuit board to its normal position set the MAX MIKE dB control to 130 dB turn the BAND switch to its maximum cow position and the dB LEVEL control to its maximum cw position Set the BAND drum so that WEIGHTING a
21. Third Octave Band Filter Sets 51 11 1966 Type 0 Class Recommendation Publication 225 1966 Octave Half Octave and Third Octave Band Filters For the Analysis of Sounds and Vibrations 1 2 DESCRIPTION The 1933 Precision Sound Level Meter and Analyzer is a portable sound analyzer including the facilities of an impulse precision sound level meter and an octave band spectrum analyzer It includes and C weighting characteristics and ten octave band filters with band center frequencies from 31 5 Hz to 16 kHz has an additional flat frequency response extending from 5 Hz to 100 kHz External filter jacks permit the use of special weighting or filters in place of the built in filter networks The instru ment has three selectable detector systems 1 a true rms detector with fast or slow characteristics 2 an impulse detector that indicates the peak of the short time rms value and 3 an absolute peak detector The indicating meter has a linear decibel scale that covers a range of 20 dB There are thirteen selectable 20 dB ranges allowing the instrument to read directly levels ranging from 10 to 150 dB re 20 uN m with appropriate microphones The 1933 is available with 1 inch and 1 2 inch microphones The microphone is connected to a detachable preamplifier which is mounted on an extendable mast Gain can be preset for any two microphones so they can be quickly changed without the need for calibration The control
22. To change gain to accommodate microphones supplied with the analyzer it is only necessary to reset the SOURCE control under top cover and adjust the MAX MIKE dB control according to the block checked in the chart inside the top cover Push in the knurled MAX MI KE dB control left side panel and turn it to the position indicated by the chart The proper setting is given adjacent to the serial number of the microphone being used The serial number is marked on the ring which is visible inside the threaded and of the microphone When the 10 dB attenuator is used its serial number governs The gain presets R9 for MIKE A and R7 for MIKE B may be set to accommodate other microphones not sup plied or the gt electret condenser microphone with the 10 dB attenuator Proceed as follows Install the microphone on the 1933 preamplifier Remove the back cover from the Analyzer to expose the preset controls see para 4 4 2 6 OPERATION Table 2 1 GAIN PRESET ADJUSTMENTS MICROPHONE SENSITIVITY Microphone Sensitivity ron sA Level dB 1 V N m Level dB 1 V ubar dB Control 26 to 36 46 to 56 36 to 46 56 to 66 130 46 to 56 66 to 76 140 56 to 66 76 to 86 Set the SOURCE control to the position desired for the new microphone Set the MAX MIKE dB control to the position indicated in Table 2 1 for the sensitivity level of the new microphone Press in and t
23. circuit to an overload comparator O4 and Q5 which lights a panel lamp when an overload condition exists The first peak or peak detector also drives a reset comparator U11 and a clock enable comparator U10 If the peak signal is too high the reset comparator is tripped causing the counter 013 to be reset When the counter is in its reset state the gain of the input programmable amplifier attenuator is set to the lowest gain possible within the bounds established by the operator through the setting of the level control The signal from the peak or peak detector then decays through an acceptance band where neither comparator is tripped to a level sufficiently low to trip the clock enable comparator The clock U12 then sends pulses to the counter which increases the gain of the input programmable amplifier attenuator in 10 dB steps until the signal at the output of the peak or peak detector falls again within the acceptance band When this occurs the process stops Each time the gain of the input program mable amplifier attenuator is changed during this settling process an equal and opposite change takes place in the gain of the analyzing programmable amplifier attenuator so that the instrument always remains calibrated and meter readings taken even during the settling interval are valid The manual override control may be used to preset the gain of the input programmable amplifier attenuator thus allowing the instrument t
24. os T i CHG m ub R 825 v RID wos XII A fi A1 Qe TiP 30 Ar 2 40 N4i2 2 4125 sles R13 LOR 0 06 5 15 3 S axo M 5 RS gt lt gt lt gt _e FRONT VIEW OF PINS ELECTRICAL PARTS LIST Fed Ref Des Description GR PartNo Mfg Code Mfg Part No Fed Stock No A Cl Capacitor 4800 uF 15 V 4450 4200 37942 20 21339 99 6 051 Lamp 6 V 5600 0316 71744 345 A DS2 Lamp 10 V 5600 0314 71744 344 6210 082 0583 1 Fuse 1 4 5330 0700 71400 MDL 0 25 5920 933 5435 2 6 Plug 0274 3610 24655 0274 3610 2 6 Terminal 138 32 7930 1600 78189 2120 06 00 A R18 Resistor 10 5 1 2 W 6100 0105 01121 RC20GF100 5905 190 8883 52 Switch Slide DPDT 7910 0832 82389 11 1118 A S3 Switch Toggle 2 Pos DPDT 7910 0791 95146 MST 205N A T1 Transformer Asm 0745 4590 24655 0745 4590 A WT12 and A WTI13 Terminal 112 40 7930 2000 CAPACITORS C2 and C3 Ceramic 33 pF 5 500 V 4404 0335 72982 831 33 pF 5 C4 and C5 Tantalum 3 3 pF 10 15 V 4450 4601 01295 15335C2 Ceramic 0 01 pF 80 20 100 4401 3100 80131 CC61 0 01 UF 80 20 5910 974 5697 DIODES thru CR4 Type 1N4003 6081 1001 14433 1N4003 CR5 Type 1N4009 6082 1012 24446 1N4009 5961
25. reduce wind noise protect against contaminants For 1 in microphone set of 4 1560 9521 For in microphone set of 4 1560 9522 1562 A Sound Level Calibrator 1562 9701 Battery spare for 1933 uses 4 8410 1500 Warranty We warrant that this product is free from defects in material and workmanship and properly used will perform in full accordance with applicable specifications If within a period of ten years after original shipment it is found after examina tion by us or our authorized representative not to meet this standard it will be re paired or at our option replaced as follows No charge for parts labor or transportation during the first three months after original shipment No charge for parts or labor during the fourth through the twelfth month after original shipment for a product returned to a GR service facility No charge for parts during the second year after original shipment for a product returned to a GR service facility During the third through the tenth year after original shipment and as long thereafter as parts are available we will maintain our repair capability and it will be available at our then prevailing schedule of charges for a product returned to a GR service facility This warranty shall not apply to any product or part thereof which has been subject to accident negligence alteration abuse or misuse nor to any parts or components that have given normal service This warranty is
26. which provides a reference to one input of 01 The other input of U1 is driven from a voltage proportional to the voltage being regulated U1 controls the base current fed to transistor Q5 When the output current increases so that the voltage drop across R4 and parallel diodes CR 12 and CR13 exceeds 1 2 V transistor Q4 conducts This diverts the base current of Q5 and shuts it off The parallel diodes and R4 limit the current from the collector of Q5 to 200 mA the required charging current for the nickel cadmium batteries used in the Analyzer and Recorder A charging period of 14 16 hours is required to fully charge batteries Potentiometer R9 TRICKLE sets the trickle charge current which is approximately 30 mA The trickle charge is adjusted for Gould Nicad 2 0 SCB batteries if other batteries are used the trickle charge must be reset Diodes CR6 CR7 and CR8 prevent the interaction of the charging and the power source supplies For the 1935 only CR6 is used in series with the charging supply for the 1933 three diodes are used The two additional diodes in the 1933 line give a voltage drop about equal to that of one battery cell Transistors Q1 and Q2 form the BATTERY CHARGED circuit They sense the voltage drop across the series com bination of R4 CR12 and CR 13 When the voltage across this network drops below 0 6 V transistor Q2 is turned off and base current for Q1 is supplied through resistor R2 Q1 is turned on a
27. 1 GENERAL 3 1 3 2 SYSTEM 3 1 3 3 OPTIRANGE SYSTEM 3 1 3 4 DETECTOR SYSTEM 3 5 FILTERS AND WEIGHTING NETWORK A 3 6 POWER 3 4 3 7 BLOCK DIAGRAM 3 5 3 1 GENERAL As its name indicates the 1933 is both a sound level meter and a spectrum analyzer 11 includes the sound level weighting networks A B and C an octave band filter that is tunable to the 10 standard center frequencies from 31 5 Hz to 16 kHz and flat or all pass characteristic that extends in frequency from 5 Hz to 100 kHz 3 2 MICROPHONE SYSTEM The analyzer uses an extendible mast arrangement that permits the microphone to be positioned more than 12 in from the instrument case and thus avoids in most cases the necessity of using a cable and tripod for precision work When a cable extension is needed the preamplifier is unplugged along with the microphone allowing the cable to be inserted between the preamplifier and instrument Because no single microphone is best for all purposes the analyzer is normally equipped with both 1 and 1 2 in diameter microphones The 1 2 in microphone is preferred for smoothest and widest frequency response at moderate and high sound pressure levels while the 1 in microphone is used when greatest sensitivity and signal to noise ratio is needed The analyzer is supplied equipped with either flat random incidence response microphones P N 1961 3000 1 in
28. 19 1 519 R35 Comp 1 kQ 6099 2105 75042 BTS 1 5 5905 681 6422 R36 Pot Cermet 10 kQ 6049 0109 80740 34331210 R37 Pot 1 kQ 6049 0106 R39 Film 7 96 1 8 W 19 6250 1796 R40 Film 113 kQ 6250 3113 R42 Comp 1 MQ 6099 5105 TRANSISTORS Q3 Type DN252 8210 1164 17856 DN252 Q4 Type TD400 8210 1169 56289 TD400 Q5 Type 2N3391A 8210 1092 17856 2N3457 Q6 Type 2N4125 8210 1125 04713 2N4125 08 2N4416 8210 1142 2N4416 5 12 PARTS amp DIAGRAMS BASE DIAGRAMS BOTTOM views TRANSISTORS GATE paainio o CASE YE AT SV rmS INPUT FOR FULL SCALE METER INDICATION DATA OuT Bu _ A J5 K RIO 30 AT 21 X 25 R25 0 Ar SIGNAL 74 OUT T TO Nr CAL CKT MOTORS SHOWN CCA WOTARY fum TUM NUMBER FING oar AFER UNF ACE FRONT REAR LO CONTACTS FIRST CONTACT Cw FROM STRUT SCREW ABOVE KEY 15 01 14 Y SECTION SECTION PANEL 5 REMAING ON E HOM LAME TUBANSE gt 713 FROM lt 4 MAIN 80 8 4724 Olu 47 4 FROM 44 M 90 8 AT e ci OM 9 8 9 Aris 722 84 ov 4684 15 4K 170 4 5 vdc FULL SCALE FULIL SCALE JNOICATION RMS oe Tee 0 vdc d8
29. 3 BNC to BNC GR 776 C Low pass filter Field assembly See Figure 4 4 Tone Burst Generator 200 500 ms pulses GR 1396 8 100 kHz Pulse Generator 200 us 10ms Pos GR 1340 Patch Cord GR874 to BNC GR 776 B Tee coaxial BNC components UG 274 U Adaptor Cable Banana plug pair to Make up microphone mast Oscilloscope Dc to 10 MHz Tektronix Type 547 5 mV sensitivity 1A1 Plug in Adaptor Cable BNC to GR874 GR776B Or equivalent 4 4 SERVICE 4 6 1933 ANALYZER TEST AND CALIBRATION 4 6 1 General The following procedures are intended for an experi enced service technician to follow in recalibrating and test ing the instrument These procedures should be followed after the instrument has been repaired or when the test of paragraph 4 3 shows that the instrument may not be work ing according to specifications A list of recommended test equipment is given in Table 4 6 It should be arranged as shown in Figure 4 1 To allow complete access to the instrument remove the back cover and swing main board out see para 4 4 4 6 2 Power Supply Check and Adjustments Power Supply Check a Set 1933 controls as follows ONOFF 25 we woe v oy SATU s vu IN b Check that the 1933 panel meter needle reads in the battery area Release BATT CHECK pushbutton c Connect an 1807 Dc Millivoltmeter from 13 to AT14 gnd on detector board This voltage should read 9 0 2 V Refer to Figure 4 5 d Connect t
30. 9630 which has a mating nine pin connector on one end and a fourteen pin connec tor on the other Secure both connectors using the thumb screws This cable completes all connections needed be tween the 1933 and 1935 Cassette Data Recorder Consult the 1935 Instruction Manual for more information on the use of this combination 2 14 USE WITH ACCELEROMETERS The 1933 can be used for vibration measurements when the microphone is replaced with an accelerometer Three accelerometers are available They are Types 1560 P52 P53 and 54 The P52 is a general purpose low cost unit with moderate high frequency performance the 1560 P53 has a wide frequency range and should be used when frequencies above about 1500 Hz must be measured the 1560 P54 is a high sensitivity pickup used to measure very low acceleration levels Table 2 2 lists the performance characteristics of these pickups when used with the 1933 A type 1560 9669 adaptor is required to connect the cable supplied with the pickups to the 1933 preamplifier input The adaptor screws onto the preamplifier in place of the microphone and the pickup cable plugs into the adaptor Because the dB LEVEL drum indicator on the 1933 can be set in any of its positions relative to the setting of the dB LEVEL control using the MIKE MAX dB control it isa simple matter to calibrate the 1933 to be direct reading in decibels referred to the ANSI standard preferred reference level of 10 cm sec 51 8 1
31. Stirling N J 07980 Military Specifications Joint Army Navy Specifications Fenwal Electronics Framingham Mass 01701 International Rectifier Corp El Segundo Calif 90245 Columbus Electronics Corp Yonkers N Y Filtron Co Flushing L I N Y 11354 Ledex Inc Dayton Ohio 45402 Barry Wright Corp Watertown Mass Sylvania Elec Prod Emporium Penn Indiana Pattern amp Model Works LaPort Ind Switchcraft Inc Chicago III 60630 Metals amp Controls Inc Attleboro Mass Milwaukee Resistor Co Milwaukee Wisc Rotron Mfg Co Inc Woodstock N Y 12498 Meissner Mfg Maguire Ind Mt Carmel Carr Fastener Co Cambridge Mass Victory Engineering Springfield N J 07081 Bearing Specialty Co San Francisco Calif Solar Electric Corp Warren Penn Union Carbide Corp New York N Y 10017 National Electronics Inc Geneva III TRW Capacitor Div Ogallala Nebr Lehigh Metal Prods Cambridge Mass 02140 TA Mfq Corp Los Angeles Calif Precision Metal Prods Stoneham Mass 02180 RCA Elect Comp amp Dev Harrison N J REC Corp New Rochelle N Y 10801 Cont Electronics Corp Brooklyn 11222 Cutler Hammer Inc Lincoln 111 Gould Nat Batteries Inc Trenton N J Cornell Dubilier Fuquay Varina N C K amp G Mfg Co New York N Y Holtzer Cabot Corp Boston Mass United Transformer Co Chicago Mallory Capacitor Co Indianapolis Ind Gulton Industries Inc Metuchen N J 08840 Westinghouse
32. The 1940 Power Supply and Charger allows the 1933 Precision Sound Level Meter and Analyzer or the 1935 Cassette Data Recorder to be operated from the power line independently of its internal batteries and also serves as a battery charger The Power Supply and Charger is supplied with a set of five rechargeable NICAD batteries four required for 1933 five for 1935 to replace the alkaline C cells The analyzer plugs directly into the Power Supply and Charger which also serves as a convenient bench stand When the supply is connected to a power line the analyzer is supplied power from a source independent from the battery while simultaneously the batteries are charged Alternately in the BATTERY mode the instrument will operate from its batteries while mounted on the charger Lamps indicate when the charger is connected to an active power line and when the batteries are fully charged When the BATTERY CHARGED light is on the batteries are maintained in the fully charged condition by trickle charging Power to the charger and instrument may be switched by external means in the LINE mode When power is disconnected the instrument will cease to operate rather than taking power from its own batteries Operation Section 2 2 1 SETUP AND CALIBRATION 2 1 2 2 AUTOMATIC OPERATION 2 2 2 3 OVERLOAD INDICATOR cw wu NN 24 CHECKING AND CHANGING BATTERIES ee x 2 5 SIGNAL OUT AC JACK 2 5 2 6 METER OUT DC JACK
33. ac voltage from pin K to chassis ground this should be between 0 475 and 0 525 V for a full scale reading on the 1933 meter SOURCE to CAL and RANGE dB Control to 100 b Measure the voltage from pin B to chassis ground as the SOURCE switch is changed Voltage should be as follows SOURCE SWITCH VOLTAGE pin B MIKE 9 9 V dc TAPE 9 V dc c Measure the d c resistance to be as follows Pin J to ground 0 Q 11 Q 10 on some early 1933 s Pin F to ground 0 9 d Measure the d c resistance to ground for pins A C E and H at various 1933 RANGE settings according to Table 4 8 X indicates a short and blank indicates open Table 4 8 RANGE DATA OUT PINA PINE RANGE switch 1 2 4 8 30 X X 40 X 50 X X 60 X X 70 X X X 80 X 90 X X 100 X X 110 X X X 120 X X 130 X X X 4 7 FINAL CALIBRATION WITH MICROPHONES 4 7 1 General The following acoustical calibration procedure should be followed when the 1933 is supplied with both the in and 1 in microphones 4 7 2 Calibration with 1 in Microphone a Attach 1 microphone with the 1961 3200 tor supplied to the 1933 preamplifier assembly b Set the controls to the following positions 1933 RANGE dB Control 120 dB full scale WEIGHTING BAND Control WEIGHTING SOURCE SW m MIKE B MANUAL OVERRIDE Control AUTO Pushbuttons d ode x xw 88 IMP SLOW
34. capacitance Table 4 5 dB LEVEL RANGE TYPICAL OCTAVE BAND NOISE LEVELS CERAMICS full scale ALL PASS Octave Band Center Frequencies 1 in Ceramic 1 2 in Ceramic 20 Hz Mike Mike 20 kHz 31 5 63 125 250 500 1k 2k 30 50 12 25 23 23 23 24 23 22 40 60 22 35 33 33 33 34 33 32 50 70 32 45 43 43 43 44 43 42 60 80 42 55 53 53 53 54 53 52 70 90 52 65 63 63 63 64 63 62 80 100 62 75 73 73 73 74 73 72 90 110 71 85 83 83 83 84 83 81 100 120 76 110 130 78 120 140 78 130 150 78 Levels not given in Table greater than 85 dB NOTE Measured at the SIGNAL OUT AC jack in dB below the output voltage corresponding to a full scale meter deflection 1 in ceramic mike with sensitivity of 40 dB and 1 2 in ceramic mike with sensitivity of 60 dB 1 V N m Both mikes have capacitance of about 390 pF Hz 4k 21 31 41 51 60 70 79 16k 23 33 43 53 63 73 79 80 85 85 85 SERVICE 4 3 OSCILLATOR GR 1310 COUNTER GR 1192 GR 776 C TO PS TPs GR 874 010 ATTENUATOR GR 1450 TB AC METER GR 1808 GR 776 1560 P77 DUMMY MIKE GR 1560 9 DISTORT METER HP 334 A TEK P60 Figure 4 1 Test set up PREAMP DC METER GR 1807 OSCILLOSCOPE GR 1560 79 6011 GR 1808 MATCHING SS J GR 808 PI NETWORK GR 1560 P77 WAVE
35. casional circumstance when the automatic system is not appropriate 3 4 DETECTOR SYSTEM The over all detector system consists of an rms detector and a peak detector in cascade The peak detector is bypassed for fast and slow while the rms detector is bypassed for absolute peak Both detectors are em ployed to provide an indication proportional to the peak of the short time rms value of the signal in the impulse mode The meter has a 20 dB range with linear decibel divisions over the entire scale A d c recorder used with the 1933 permits graphic level recording over a wide dynamic range is driven from the METER OUT DC jack which provides a voltage or cur rent proportional to the logarithm of the detected signal i e linear in decibels over a range of 60 dB including a crest factor allowance of 20 dB An output of 1 mA is available from this jack at full scale on the meter and any load impedance can be connected without affecting the source linearity or the indication of the meter Peak overload detectors at two critical points in the circuitry trigger the OVERLOAD lamp on the panel of the 1933 A meter indication is valid when the overload lamp is off but invalid when it is on Any load impedance can be connected to the analyzer s SIGNAL OUT AC jack and an undistorted signal will be delivered to any linear load impedance 3 5 FILTERS AND WEIGHTING NETWORKS The octave band filters in the 1933 are resistance
36. connect output of GR oscillators and or attenuators to input of 1933 through 1560 P9 dummy microphone 2 18 1940 POWER SUPPLY AND CHARGER The 1940 Power Supply and Charger permits the 1933 Precision Sound Level Meter and Analyzer to be operated directly from the power line and also permits use of rechargeable batteries There is no change in accuracy when the 1940 power supply is used The 1940 is supplied with rechargeable batteries which are used to replace the alkaline Table 2 3 TYPICAL MINIMUM MEASUREABLE NOISE LEVELS dB 20 uN m Microphone Typical Type Sensi tivity Level dB re 1 V N m A B FLAT 1 in Electret Condenser 22 21 22 32 31 32 36 42 34 35 39 45 24 22 23 34 Electret Condenser 1 in Ceramic Ceramic 46 44 45 56 Guaranteed minimum measurable levels with in electret condenser microphone Octave Band 31 5 63 125 250 500 1K 2K 4K 8K 16K 18 16 14 252 11 11 13 15 17 19 32 30 28 26 25 23 24 24 24 26 16 13 12 11 11 13 14 16 18 21 38 35 34 33 33 35 36 38 40 43 OPERATION 2 11 energizers supplied with the 1933 the 1940 is to be used to provide only power line operation it is unnecessary to install the rechargeable batteries CAUTION Do not use the 1940 when alkaline energizers are in the 1933 Five recessed jacks on the bottom of the 1933 accept plugs on the 1940 fully plug the instruments together The 1940 also serves as a convenient bench stand To po
37. of Blanking Period a Retain the set up of Figure 4 1 and set the controls as follows 1310 Frequency m s s ww X9 Frequency Range 200 Hz 2 kHz 55 sos x w 1450 TB Attenuation 30 dB 1933 RANGE dB Control 100 dB full scale WEIGHTING BAND Control 1 kHz Band SOURCE TAPE Tektronix 547 Scope Channel a s cw x luputselGclOt 2 5 o 4 9 amp gt a BE Triggering x v G9 wit oR GONE e x T X X X ow s y YS 2 52 ARDI a Trigger Level Negative transition 50 ms 4 8 SERVICE b Adjust the 1310 output for full scale on the 1933 panel meter c Connect scope X1 probe to pin 11 of U12 d Adjust the oscilloscope triggering to obtain a negative pulse every time the 1450 is switched from 30 to 10 dB or from 10 to 30 dB Wait approximately 5 seconds between switchings e Adjust R47 on the main board for a pulse width of 150 ms 4 6 8 Meter Tracking and D c Output Checks Meter Tracking a Use the setup of Figure 4 1 and set the controls as follows 1310 Oscillator Fraduaney u x o9 Frequency Range 200 Hz 2 kHz Output Lowell s 2 et ww v 1450 TB Attenuation 44 dB 1933 WEIGHTING BAND Control WEIGHTING RANGE dB Control 100 d
38. source on is 83 dB the difference is 6 dB and the correction from the curve of Figure 2 8 is 1 2 dB so the corrected octave band level is 81 8 dB The correction must be determined for each octave band or weighting characteristic of interest 2 15 2 Precautions at Low Sound Levels When making low level noise measurements with the microphone mounted on the 1933 mast a sound is transmitted to the microphone when the meter pointer strikes the lower meter stop This sound can cause the meter pointer to read up scale again and if the instrument is set to METER FAST a sustained oscillation can occur To avoid this condition use the SLOW meter response or mount the microphone and preamplifier away from the Sound Level Meter and Analyzer using the extension cable supplied Another feed back effect may occur when an earphone is connected to the AC OUTPUT The feedback path is closed through the path between the earphone and the microphone causing the earphone to howl The solution to this problem is to separate the earphone and microphone as much as possible In extreme cases it may be necessary to use the preamplifier extension cable supplied Wind Effects When the microphone is used in wind a low frequency noise is generated by turbulence caused when the wind passes around the microphone The level of this noise may be high enough to obscure the sound to be measured and in some cases to overload the analyzer This noise can be greatly r
39. systems include more equipment than the 1933 9714 and 9715 systems Case dimensions are L x Wx D 22 3 16 x 15 3 8 x 8 5 8 inches overall They include all the accessories listed in Table 1 4 for the 1933 9700 and 9702 and in addition the following 1 Carrying and storage case carry on size 1 Windscreen for 1 inch microphone 1 Windscreen for 1 2 inch microphone 1 Dummy microphone 1560 P9 35 pf to simulate 1 2 inch electret condenser microphone 1 Sound Level Calibrator 1562 with Instruction Manual Adaptor for 1 inch microphone Adaptor for 1 2 inch microphone Battery Carrying case 1 6 INTRODUCTION 1 60 ft microphone extension cable on reel 1 Tripod 1 Earphone ear insert type for monitoring signal from 1933 Sound Analysis System 1933 9712 and 9713 These systems include all the components of the 1933 9710 and 9711 systems plus a companion cassette data recorder and its accessories Case dimensions are L x W x D 22 3 16 x 15 3 8 x 8 5 8 inches overall They include all the accessories included with the 1933 9710 and 9711 systems and in addition the following 1 Cassette Data Recorder 1935 9700 with its acces sories including 30 minute standard cassette Batteries alkaline c cells Coiled cable to connect Sound Level Meter and Analyzer to Data Recorder 1 Playback cable to connect output of recorder to input at mast of analyzer i 5 1 1 7 POWER SUPPLY AND CHARGER
40. the 90 preamplifier position both with and without the Operators presence Figure 2 7 shows the error introduced by the instrument case no operator present when the preamplifier is in its 0 position and the mast is pointed at the source This position should be avoided if possible All error curves were obtained using pure tones in a free field anechoic space and can be considered worst case For normal industrial or community noise environ ments or indoors error will be considerably smaller and can be ignored The 10 ft cable supplied with the 1933 1933 9600 or the 60 ft cable available 1933 9601 can be used to allow both operator and instrument case to be positioned still farther from the microphone thus eliminating the proxi mity errors The microphone preamplifier is then mounted on the 1560 9590 tripod or by other means 2 10 EXTENSION CABLES A ten foot extension cable 1933 9600 is supplied with the Sound Level Meter and Analyzer In addition a sixty foot extension cable 1933 9601 is supplied with the RELATIVE LEVEL dB B RELATIVE LEVEL dB RELATIVE LEVEL dB FREQUENCY Hz INSTRUMENT CASE ONLY ENVELOPE OF ERROR 10K 20K 30K Sound Analysis Systems 1933 9710 9711 9712 and 9713 or it may be ordered separately Cables are inserted between the removable preamplifier and the mast Because the preamplifier and not the microphone drives the cable there is no
41. through the phone jacks and will be broken by inserting the phone plugs that connect the external filter The output impedance at the TO EXT FILTER jack is less than 50 Q and the filter connected must have an input impedance of 600 Q or more The input impedance at the FROM EXT FILTER jack is 60 kQ and the filter connected must not have an output impedance of more than 6 The maximum voltage open circuit at the TO EXT FILTER jack is about 1 volt peak so that the external filter should be capable of handling this signal level if the full 20 dB crest factor capacity of the analyzer is to be realized 2 8 CHANGING MICROPHONES Because no single microphone is best for all applications the analyzer includes a SOURCE control that allows selection of two preset gains These gains are adjusted at the factory to accomodate the microphones supplied with the analyzer t is therefore not necessary to recalibrate the analyzer when changing microphones When the analyzer is supplied with only a 1 2 inch electret condenser microphone 1933 9701 and 1933 9703 the gain presets are adjusted to accomodate both the microphone cartridge and the microphone car tridge with the 10 dB attenuator supplied in place When the analyzer is supplied with both 1 2 inch and 1 inch electret condenser microphones the gain presets are ad justed to accomodate the two microphone cartridges only The analyzer is not calibrated for use with the 10 dB Attenuator
42. to 2000 Hz The earphone 1935 0410 a small in the ear type earphone is used to listen to the sound being measured at the SIGNAL OUT AC jack It is helpful in determining the nature or source of a noise and providing assurance that the analyzer is operating properly The tripod 1560 9590 a compact unit with elevating center post is used to support the microphone and pre amplifier when they are used at the end of an extension cable It can also be used to support the complete 1933 The tripod has a swivel head that permits 0 to 90 adjustment in one direction and O to 20 for proper orientation of a microphone with flat random incidence response in the other direction The head has two concentric removable sleeves for mounting 3 4 inch diam eter devices or 1 2 inch diameter preamplifiers It also has a standard 1 4 20 screw and a locking nut for mounting the 1933 The friction in the swivel can be adjusted by removing the swivel from the center post of the tripod and adjusting the allen head screw in the base of the swivel The Microphone Attenuator 1962 3200 is a 10 dB capacitive attenuator to be used with the 1962 9601 or 9602 1 2 inch electret condenser microphones when sound levels above 130 dB are to be measured This unit is inserted between the 1 2 inch microphone and the pream plifier input The Cassette Data Recorder 1935 is a major accessory for the 1933 and is supplied with many of its accessories in the 1933 9712
43. 0 9570 1972 9601 1961 9602 1962 9602 1933 9601 1933 9602 1560 9677 1560 9679 1560 9678 1560 9680 1560 9675 1560 4522 1560 4521 1562 9702 1560 9590 1935 9701 1940 9701 1560 9609 1 6 SOUND ANALYSIS SYSTEMS The 1933 Precision Sound Level Meter and Analyzer is available as part of six complete sound analysis systems Each system is made up of the Sound Level Meter and Analyzer with selected accessories packaged in a durable traveling case The case has foam liners with cutouts to accommodate components of the system A file folder is supplied for storage of instruction manuals notes and data Sound Analysis Systems 1933 9714 and 9715 These systems are assembled in an attache case 1933 9714 with random incidence microphones and 1933 9715 with perpendicular incidence microphones Case dimensions are L x W x D 18 3 8 x 15 x 6 1 4 inches overall They include all of the accessories listed in Table 1 4 for the 1933 9700 and 9702 and in addition the fol lowing 1 Carrying and storage case attache size 1 Windscreen for 1 inch microphone 1 Windscreen for 1 2 inch microphone 1 Dummy microphone 1560 P9 35 pf to simulate 1 2 inch electret condenser microphone 1 Sound Level Calibrator 1562 with Instruction Manual Adaptor for 1 inch microphone Adaptor for 1 2 inch microphone Battery 1 Earphone ear insert type for monitoring signal from 1933 Sound Analysis Systems 1933 9710 and 9711 These
44. 096 LF 4862 1780 19396 PCR700 Cli Plastic 096 UF 4862 2000 19396 PCR700 C12 and C13 Cap Ceramic 0 1 80 20 100 4403 4100 80131 CC63 1 pF 80 20 C14 and CIS Cap Ceramic 01 pF 80 20 100 V 4401 3100 80131 1 01 pF 480 209 C16 and C17 Plastic 047 uF 4860 9473 84411 663UW 047 uF C18 thru CAI Ceramic 30 pF 4404 0305 72982 831 30 pF 575 C22 Plastic 047 LF 4860 9473 84411 663UW 047 C23 Tantalum 47 pF 4450 4310 72982 831 47 pF C24 Ceramic 001 uF 4404 2108 72982 831 001 pF C25 thru C27 Ceramic 01 pF 4401 3100 80131 6 01 pF 80 20 C28 and C29 Tantalum 47 pF 4450 5712 37942 MTP C30 and C31 Tantalum 4 7 pF 4450 4700 56289 1500465 0015 2 C32 C33 Ceramic 001 pF 4404 2108 72982 831 001 uF C34 and C35 Ceramic 01 pF 4401 3100 80131 CC61 01 uF 80 20 C36 Cap Ceramic 0 47 uF 109 50 V 4400 6358 09392 8141 MO050 W5R473K C37 and C38 Ceramic 1 4400 2070 80183 5C13 1 pF 20 C39 Tantalum 300 4450 5724 37942 TT 300 pF C40 Tantalum 80 pF 4450 6300 37942 80 pF C42 Ceramic 01 pF 4401 3100 80131 CC61 01 pF 80 20 C43 Cap Ceramic 5 1 pF 5 500 V 4411 9515 80131 CC60 5 1 pF 5 C44 Ceramic 120 pF 4404 1128 72982 831 120 pF C45 Tantalum 47 pF 4450 5500 56289 150D476X0006B2 C46 Ceramic 120 uF 4404 1128 72982 831 120 uF Tantalum 4 7 4450 4700 56289 150D465X0015B2 48 49 Ceramic 30 pF 5 500 4404 0305 72982 831
45. 1 4 1 5 ACCESSORIES AVAILABLE 1 6 1 6 SOUND ANALYSIS SYSTEMS x 1 7 POWER SUPPLY AND CHARGER w 1 6 1 1 PURPOSE The 1933 Precision Sound Level Meter and lyzer is a light weight portable sound analyzer intended to make precision sound level measurements and octave band analyses It operates for 20 hours on self contained batteries and is ideally suited for field use Its unique opti range design permits one knob control of the level range In addition to making measurements on site the 1933 operates with its accessory 1935 Cassette Data Recorder to collect data for later analysis in a laboratory The 1933 is capable of making all measurements required under the Safety and Health Standards of the Walsh Healey Public Contracts Act 41USC 351 et seq and the Occupational Safety and Health Act OSHA of 1970 84 STAT 1590 including the measurement of the absolute peak sound level of impact sounds The 1933 complies fully with the following standards ANSI Standard Specification for Sound Level Meters 1 4 1971 1 Precision IEC Recommendation Publication 179 1965 Precision Sound Level Meters Current Draft Supplement to IEC Publication 179 Preci sion Sound Level Meters Additional requirements for the measurement of Impulsive Sounds IEC Recommendation Publication 123 1961 Sound Level Meters ANSI Standard Specifications for Octave Half Octave and
46. 1 and set the controls as follows 1310 Oscillator Frequency Dial 3 15 Frequency Range 20 Hz 200 Hz Output Level s s 0 1450 Attenuation 40 dB 1933 RANGE dB Control 90 dB full scale WEIGHTING BAND Control 31 5 Hz BAND Pushbuttons IMP SLOW out fast b Connect the scope to the TO EXTERNAL FILTER jack A J1 via 1560 P79 cable c Adjust the 1310 output level for a full scale reading on the 1933 panel meter Note the dB reading on the 1808 AC Millivoltmeter connected to 1310 output d Move the 1933 WEIGHTING BAND control to 1 kHz BAND Slowly increase the 1310 output level until the wave form on the scope suddenly decreases This should occur 13 5 14 5 dB above the previously noted level at full scale The drop in level corresponds to the U13 counter reset 4 14 SERVICE e Within 4 seconds the signal on the scope should settle to a new level about 10 dB less than the level that existed just before the reset of 013 counter f Reduce the 1310 output level and note the point at which the scope level suddenly increases by 10 dB This should be 2 to 4 dB less than the reset level in step d 4 6 15 Overload Detector Check Use the same setup as Figure 4 1 and set the controls as follows 1310 Oscillator Frequency Dial e a s e 10 Frequency Range 200 Hz 2 kHz oou 5 3 ow 3 amp 59 1450 TB Attenuation 70 dB 1933 RANGE dB Control
47. 1450 TB Attenuation 60 dB Table 4 7 OCTAVE BAND LIMITS Nominal Exact Center Center 3 dB down Freq Freq Limits 1 5 to 4 5 Hz Hz Lower Upper 31 5 31 62 22 70 44 05 63 63 09 45 29 87 88 125 125 9 90 37 175 4 250 25 16 180 5 349 9 500 501 2 359 8 698 2 1k 1000 717 9 1393 2k 1995 1432 2779 4k 3981 2858 5545 8k 7943 5702 11065 16 k 15848 11 890 21 077 334 A Function Sw Voltmeter Meter Range Sw 0 1V 1933 WEIGHTING BAND Control 1 kHz Band R23 Main Board fully RANGE dB Control 80 dB b Connect an HP334A through a GR 274 adaptor and a X1 probe to BUFF 1 OUT at the junction of the red and grey coaxial cables Set 1310 output for 5 dB as read on the 334 A c Attach X1 probe to TP1 and set the 334 A to the 0 3 V range Adjust the 1310 for peak Adjust R15 for a 3 5 dB reading on 334 A 11 5 dB gain over BUFF 1 d Attach X1 probe to TP3 and move the 334 A to its 1 V range Slowly sweep 1310 between 700 Hz and 1400 Hz Note peak on both sides of 1 kHz Adjust R18 until peak on low side is same as that on high side R18 affects low side more than high side e Attach X1 probe to BUFF 1 out and set 1310 1 kHz 334 y 0 1 V range f Adjust 1310 output for 7 dB reading on 334 g Attach X1 probe to TP3 and move the 334 A to the 0 3 V range h Adjust R23 for a reading of 1 4 dB on 334 18 4 dB gain over BUFF 1 OUT 4 6 4 Filter Response Check Use the set up o
48. 2 kHz 20 50 70 100kHz 200 Hr 5 FREQUENCY Hz Correction to be added algebraically to perpendicular incidence response Typical directional response of the microphone to find random and grazing incidence free field response Figure 3 4 Characteristics for electret microphone flat perpendicular incidence response THEORY 3 3 GAIN OF INPUT AMPLIFIER ATTENUATOR dB 0 20 m GAIN OF ANALYZING AMPLIFIER ATTENUATOR dB POSSIBLE COMBINATIONS OF INPUT PROGRAMMABLE AMPLIFIER ATTENUATOR AND ANALYZING PROGRAMMABLE AMPLIFIER ATTENUATOR FOR EACH SETTING OF THE LEVEL CONTOL Figure 3 5 Automatic level range control diagram input amplifier attenuator and an analyzing amplifier atten uator see Figure 5 3 in such a way as to maximize the peak level of the signal being fed to the filter without overload In the worst case when a signal is suddenly applied to the instrument about 4 seconds will elapse before the automatic system gives the optimum combina tion of gains for the input amplifier attenuator and analyzing amplifier attenuator This is considerably less time than what would be required to manipulate dual manual range controls And unlike the manual system during this settling period the instrument is fully operative and capable of giving valid meter indications A number of important benefits accrue from the automatic system 1 Because there is only a singl
49. 4 2 located at the front corners of the meter and the two that Select each octave band filter setting the oscillator to fasten the detector circuit board to the meter barrel the center frequency of the filter and noting the meter accessible after the main etched board is swung out readings When all octave bands are considered the highest meter reading should not differ from the lowest meter 4 5 INTERNAL NOISE DYNAMIC RANGE reading by more than 2 0 dB The noise floor and dynamic range of the 1933 is given in Tables 4 3 4 4 and 4 5 These tables show the noise 4 4 OPENING THE CASE levels for each setting of the dB LEVEL control in octave Most circuits in the 1933 are accessible by removing the bands and broad band ALL PASS The levels are typical back cover To remove this cover first remove the two and are given in decibels below the SIGNAL OUT AC jack screws recessed in the holes in the bottom and the screw voltage corresponding to a full scale meter deflection when recessed in a hole located under the top cover between the the 1933 is set to C WEIGHTING The three charts cover SOURCE control and the MANUAL OVERRIDE control one inch and one half inch electret condenser and ceramic Then pull the cover straight back away from the instru microphones with typical sensitivities are given ment To swing the main etched circuit board out for access Because the peak overload level of the 1933 is more than to components remove the two screws located
50. 4154 or 1N4009 6082 1012 24446 1N4009 5961 892 8700 LAMPS 051 Incandescent 5 5000 1300 24655 5600 1300 RESISTORS R2 Comp 2 4 MQ 6099 5245 75042 BTS 2 4 9 5 R3 Film 2 74 k2 6250 1274 75042 CEA 2 74 kQ 1 5905 834 7208 R7 Res Film 1 74 1 1 8 W 6250 1174 75042 CEA 1 74 1 R8 Res Film 23 2 19 1 8 W 6250 2232 75042 CEA 2 32 1 R9 W W 1 27 2 6620 1041 R10 Pot 6049 0297 01121 2H5021 R12 Comp 1 MQ 6099 5105 SWITCHES 51 Pushbutton 7880 2110 71590 PB 15 52 Waf 7890 8290 76854 7890 8290 53 Rot Waf 7890 8291 76854 7890 8291 TRANSISTORS Q1 Type E 113 8210 1229 23136 E 113 INTERCONNECTIONS FER tft NEE ey mmm TERM 5 56 2 37 TN FUNE DETECTOR BO e 2 25 BAT SSS 27 5 6 23 30 3 2 33 iW 45 5 8 PARTS amp DIAGRAMS wiTCHto MANUAL CVER RIDE SWITCHING Sin SIGNAL GND CROAT CAL INPUT UM PER FEV FUN sS wire HE D SHUNT GAT MECN T CATE CAT O FOUE TO CAL ty LOOK 4 esed a CONTAC gt 22 2 gt 1 PEAR CONTR 3 rE CRG 7579 j 4 4 6 400 150MS 0 L BLNK _ CLOCK ENABLE COMPARATOR u CIR 12 ceo I 30 INHIBIT 5
51. 5 0 5 1 4 W 6099 0155 75042 BTS 15 Q 5 SOCKET IC8 Cont 7540 3461 09056 7058 295 5 TRANSISTORS Q1 and Q2 Type 2N4125 8210 1125 04713 2N4125 Q3 Type 2N4221 8210 1127 04713 2N4221 Q4 Type 2N4125 8210 1125 04713 2N4125 Q5 and Q6 Type TIP 30 8210 1191 96214 30 07 2 4125 8210 1125 04713 2N4125 08 2 3391 8210 1092 24454 2N3391A
52. 5 4 OVER ALL BLOCK DIAGRAM SCHEMATIC DIAGRAM FOR 1933 ANALOG CIRCUITS 57 SCHEMATIC DIAGRAM FOR 1933 DIGITAL CIRCUITS 59 SCHEMATIC DIAGRAM FOR 1933 POWER SUPPLY 5 11 SCHEMATIC DIAGRAM FOR 1933 DETECTOR CIRCUIT 5 13 NOTE Each reference designator used in our schematic diagrams and circuit descriptions includes an initial letter before a hyphen to identify the subassembly except that A refers to the main frame The numeric portion of each designator is generally shorter than would be the case block of numbers were assigned to each sub assembly The designation of wire tie points 15 AT anchor terminal The letter before the hyphen may be omitted only if clearly under stood as within a subassembly schematic dia gram Examples B R8 designates B board resistor 8 D AT2 D board wire tie point 2 CR6 on the V schematic is a shortened form of V CR6 V board diode 6 The instrument may contain A R1 B R1 C R1 and D R1 Parts lists and etch d board drawings appear just before corresponding reference views or schematic diagrams PARTS amp DIAGRAMS 5 1 6 Figure 5 1 Mechanical parts 1933 front and right side MECHANICAL PARTS LIST Fig Fed Ref Qnt Description GR Part No Mfg Code Mfg Part No Fed Stock No 1 7 Pushbutton black FLAT 5511 0403 24655 5511 0403 or ext BAT CHECK METER IMP SLOW 1 Microphone housing COVER asm 1
53. 7040 BTS 6 2 59 CEA 909 Q 19 597020 CEA 10 0 19 CEA 909 21 597020 CEA 10 0 1 CEA 15 0 17 CEA 58 8 19 CEA 2 29 1 62 500 CEA 10 0 19 CEA 76 8 17 4 75 19 CEA 19 0 177 BTS 47 5 BTS 10 57 BTS 47 59 CEA 84 5 19 CEA 6 34 19 CEA 56 2 19 34 8 19 BTS 10 59 BTS 24 59 CEA 9 09 1 BTS 510 59 300 59 18 0 19 BTS 1 kQ 59 BTS 4 7 59 BTS 2 2 57 BTS 510 59 3329 1 304 BTS 100 59 BTS 1 5 BTS 1 5 5 BTS 470 2 5 BTS 10 5 BTS 4 3 5 BTS 11 k2 5 BTS 100 5 BTS 4 7 9 5 BTS 2 5 BTS 47 5 CEA 9 09 1 1 58 1 BTS 620 2 57 1933 0800 1833 0820 1933 0810 1933 0820 1933 0810 Fed Stock No 5905 683 2246 5905 883 4847 5905 883 4847 5905 581 7626 5905 855 3176 5905 883 4847 5905 683 2246 5905 683 2238 5905 683 2246 5905 892 6968 5905 683 2238 5905 655 3167 5905 801 8272 5905 681 8854 5905 686 3373 5905 681 6422 5905 686 9992 5905 723 5251 5905 801 8272 5905 686 3129 3905 683 2242 5905 683 2238 5905 686 3129 5905 686 9992 5905 686 3370 5905 683 2246 5905 655 3167 5905 755 0677 5905 801 6998 Ref Des Description
54. 9 596 1 892 8700 596 1 893 6762 5961 892 8700 5960 877 8255 5960 984 3570 Ref Des Description RESISTORS R1A and R1B Comp 4 3 M2 to 6 2 R2 Por Cermet 10 kQ R3 Comp 16 k amp R4 thru R6 Comp 47 R7 Cermet 20 R8 Comp 5 6 R9 Pot Cermet 20 k2 R10 Comp 5 6 kQ Ril Comp 6 2 R12 Pot Cermet 5 kQ R13 Comp 6 2 kQ R14 Film 909 2 R15 Pot Cermet 200 2 R16 Film 10 0 R17 Film 909 22 R18 Pot Cermet 200 2 R19 Film 10 0 R20 Film 15 0 k2 R21 Film 58 8 kQ R22 Film 2 29 k amp R23 Pot Cermet 500 2 R24 Film 10 0 k2 R25 Film 76 8 R26 Film 4 75 kQ R27 Film 19 0 R28 Comp 47 M9 R29 and R30 Comp 10 R31 Comp 47 MQ R32 Film 84 5 R33 Film 6 34 R34 Film 56 2 R35 Film 34 8 36 Comp 10 k2 R37 Comp 24 R38 Film 9 09 k2 R39 Comp 510 R40 Comp 300 R41 Film 18 0 kQ R42 Comp 1 R44 Comp 4 7 MQ R45 Comp 2 2 9 R46 Comp 510 k9 R47 Cermet 500 kQ R48 thru R55 Comp 100 k2 R56 Comp 1 M2 57 and R57B Comp 4 3 to 6 2 9 R58 and R59 Comp 1 5 kQ R60 Comp 470 2 R61 Comp 10 k2 R62 Comp 4 3 R63 Comp 11 kQ R64 Comp 100 k2 R65 Comp 4 7 MQ R67 and R68 Comp 2 R69 Comp 47 R70 Film 9 09 R71 Film 1 58 R72 Comp 620 2 RESISTOR NETWORKS 21 and Z2 Resistor Network
55. 933 1080 24655 1933 1080 1 Microphone mast asm 1933 2000 24655 1933 2000 2 Knob Asm 5520 5435 24655 5520 5435 requires bushing 4143 3161 24655 4143 3161 1 Pushbutton white ON OFF 5511 0406 24655 5511 0406 1 Switch toggle A S1 IMPULSE 7910 0460 71744 123 021 118 PEAK IMPACT 7 1 Cover battery compartment 1933 8030 24655 1933 8030 MISCELLANEOUS 1 Knob black SOURCE Mike A 1933 6091 24655 1933 6091 B TAPE CAL 1 Knob black 1933 6092 24655 1933 6092 Auto MANUAL OVERRIDE dB Meter assembly 5730 1933 24655 5730 1933 5 2 PARTS amp DIAGRAMS Sa rama vt Figure 5 2 Mechanical parts 1933 left side ANS amp IEC Standards ANS 197 type 1 precession ANS 51 11 1966 ines 11 BER 452 tn ext fiver MECHANICAL PARTS LIST cont Fig Fed Ref Ont Description GR Part No Mfg Code Mfg Part No Fed Stock No 1 1 Bottom cover asm 1933 1070 24655 1933 1070 2 1 Knob assy 1933 7071 24655 1933 7071 3 1 Connector 5 DATA OUT 4230 1210 24655 4230 1210 4 1 1933 1040 24655 1933 1040 5 4 Connector miniature 1 2 3 4 4260 1110 82389 TR 2A TO EXT FILTER FROM EXT FILTER METER OUT DC SIGNAL OUT AC 6 1 Battery Compartment Asm 1933 2010 24655 1933 2010 PARTS amp DIAGRAMS 5 3 Code 00192 00194 00434 00656 01009 01121 01236 01255 01295 02114 02606 02660 02768 03042 03508 03636 03888 03911 04643
56. 95 Y vq amp 2 8 y 792 5 SHAS SL 070 7 WN 6 NOILIINNGD 05600 9242217 72 7 5 SNOVLIANNO Nibbly Ref Des Description CAPACITORS Cl Ceramic 001 pF 10 200 V C2 Tantalum 6 8 pF 20 15 V C3 Tantalum 1 0 pF 209 35 CONNECTORS Pl Threaded coaxial P2 Microphone 4 term RESISTORS R1 Res Comp 2 2 G 20 1 8 W R2 Res 22 Q 5 1 8 W R3 100 5 1 8 W 12 5 1 8 W 4 6 2 5 1 8 W Q1 3 3 59 1 8 W 1055 R5 Comp 4 7 5 1 8 W R6 100 5 1 8 W R7 Comp 3 0 59 1 8 W R8 20 2 5 1 8 W TRANSISTORS Q1 2N3457 Q2 D30A3 gt 5 10 PARTS amp DIAGRAMS GR PartNo Mfg Code 4400 6440 4450 6401 4450 6400 1933 0410 6098 8228 6098 0225 6098 4105 6098 3125 6098 2625 6098 2335 6098 2475 6098 4105 6098 2305 6098 0105 8210 1082 8210 1204 ELECTRICAL PARTS LIST Fed 72982 24655 56289 24655 01121 01121 01121 01121 01121 01121 01121 01121 01121 01121 17856 24454 Mfg No Fed Stock No Preamplifier Board P N 1933 4795 8121 026 Y5RO 102K 4450 6401 162 D 1933 0410 2 2 G 2 22 7 5 100 59 12 59 6 2 59 3 3 5 4 7 59 1 8 W 100 59 3 0 59 10 2 5
57. 969 2 14 1 Calibration The following calibration procedure is recommended to make the 1933 direct reading in dB re 10 cm sec other methods can also be used The procedure requires use of a Type 1557 Vibration Calibrator which generates a reference level of 1 rms at a frequency of 100 Hz a When using either the 1560 P52 or the 1560 P53 accelerometers set the MAX MIKE dB control to 140 When using the 1560 P54 accelerometer set the MAX MIKE dB control to 120 b Set the dB LEVEL control for 120 dB full scale c Mount the accelerometer on the Type 1557 Vibration Calibrator and adjust the calibrator to produce a level of 1 g rms See instruction manual supplied with the calibrator Table 2 2 ACCELEROMETER PERFORMANCE CHARACTERISTICST Nominal Resonant Pickup Sens Freq Frequency Range dB mv g Hz Hz 9 in sec 10 cm sec 1560 P52 70 3200 5 1600 8 107 to 7 0036 2700 20 140 1560 P53 70 27000 5 14000 8 107 to 7 0036 2700 20 140 1560 P54 700 5000 5 2500 8x1077 to 0 7 00036 270 0 120 Minimum levels measureable only in middle frequency octave bands TSee also Table 2 4 d Set the 1933 to WEIGHTING and FLAT and turn it ON e Set the SOURCE control to preset A or B as desired and adjust the appropriate gain preset R9 for A R7 for B for a meter indication of 119 8 dB R9 and R7 are found under the back cover See pare 4 4 for removal of cover 2 14 2 Operation The ins
58. 9713 Sound Analysis Systems Instructions for the recorder and its accessories are given in the operating instruction book for the 1935 1933 9602 miniature phone plug to 1933 mast connec tor is used to connect the output of the 1935 Cassette Data Recorder to the input of the 1933 It is supplied with the 1935 Cassette Data Recorder This cable can also be used to connect the 1560 P62 Power Supply to the input of the 1933 thus allowing the 1560 P42 Preamplifier to be substituted for the 1933 Preamplifier The 1560 P42 is used for driving very long input cables 1560 9677 miniature phone plug to double banana plug used to connect METER OUT DC SIGNAL OUT AC or FILTER jacks of 1933 to instruments with GR or equivalent binding post terminals 1560 9678 miniature phone plug to standard phone plug used to connect jacks on 1933 to instruments with standard phone jacks 1560 9679 miniature phone plug to BNC connector used to connect jacks on 1933 to instruments fitted with BNC connectors 1560 9680 miniature phone plug to standard phone jack adapts miniature phone jacks on 1933 to connect with standard phone patch cords Can be used to connect SIGNAL OUT AC jack of 1933 to 1556 Impact Noise Analyzer 1560 9675 miniature phone plug to special double banana plug with molded in 200 Q resistor used to connect METER OUT DC jack of 1933 to input of Simpson 2745 DC recorder 0776 9701 shielded double banana plug to BNC connec tor used to
59. A BANDWIDTH GPS i i v v s 428 Sires 4 X x4 MODE NORMAL READING a m RELATIVE FULL SCALE KNOB lt x FULL SCALE DIAL 10 Input not exceed METER SPEED FAST b Connect the 1900 A Wave AEE input to the 1933 A J4 SIGNAL OUT AC jack via GR 1560 P77 cable c Adjust the 1310 Oscillator for a full scale reading on the 1933 Tune the 1900 WAVE ANALYZER to the fre quency of the oscillator d Adjust the GAIN control on the 1900 WAVE ANA LYZER for 4 dB reference on the 1900 panel meter Set the 1450 TB attenuator and the 1933 RANGE dB Control to the positions indicated the table below each case check the 1900 Wave Analyzer panel meter read ing to be within the stated tolerances f Repeat the RANGE dB control test at 32 Hz and 50 kHz on FLAT position Use 3 Hz BANDWIDTH on the 1900 A for the 32 Hz test 1933 RANGE 1900 1450 dB Control panel meter 40 90 4 dB set 30 100 4dB 0 5dB 20 110 4dB 0 5dB 10 120 4 dB 0 5 dB 0 130 4 dB 0 5 dB 50 80 4 dB 0 5 dB 60 70 4 dB 0 5 dB 70 60 4 dB 0 5 dB 80 50 4 dB 0 5 dB 90 40 4 dB 0 5dB 100 30 4 dB 0 5 dB Set the 1900 Meter Speed Sw to slow MICROPLUG SWITCHCRAFT TYPE 850 SHEET METAL CASE Figure 4 4 100 kHz low pass filter 4 10 SERVICE GROUND TO CASE 4 6 11 Noise and Signal Out Check Noise NOTE The instrument must have covers installed
60. ANALYZER GR 1900 1933 6 X Table 4 6 RECOMMENDED TEST EQUIPMENT Instrument Requirements Recommended Instrument Requirements Recommended Patch Cord Miniphone to GR 1560 P77 Oscilloscope Probe X1 Tektronix P6011 double banana 1560 9677 Calibrator 114 dB SPL GR 1562 Oscillator 2 Hz 2 MHz GR 1310 Oscillator 125 Hz 2 kHz O 20 V open ckt Wave Analyzer 20 Hz to 54 kHz GR 1900 A Oscillator 10 Hz 100 kHz GR 1309 Oscillator linear freq scale lt 0 05 distortion Patch Cords 2 Double banana plugs GR 274 NQ Dc Voltmeter 500 1807 Range 0 15 Microvoltmeter Adaptor plug Shielded banana plug GR 274 QBJ 0 1 accuracy Nanoammeter to BNC male Ac Voltmeter 0 150 V GR 1808 Milli Adaptor cable Banana plug 274 1 voltmeter with 1808 to BNC male P1 Probe Adaptor Adaptor cable BNC male to minia GR 1560 P79 Counter General Purpose GR 1192 ture phone plug 1560 9679 Distortion Analyzer 100 Hz 20 kHz Model 334 Phone plug standard GR 1560 P78 300 uV 300 Vrms Distortion Analyzer to miniature phone plug Resistive Load 600 2 5 GR 500 G Resistor Adaptor Banana plug pair GR 874 010 to GR874 0874 9876 Decade Attenuator 0 1 dB 1 dB GR 1450 TB 10 dB steps Decade Attenuator Patch Cords 2 Shielded double 776 plug to BNC Dummy Microphone 35 pF source GR 1560 P9 BNC jack 460 60 Patch Cords
61. B full scale 2 wo vos UMP FLAT Pushbuttons em sx x b Adjust the 1310 oscillator of 96 on the 1933 panel meter Check other points as follows 1450 TB 1933 Panel Meter dB 44 dB 96 dB set 40 dB 99 8 100 2 50 dB 89 6 90 2 55 dB 84 5 85 5 60 dB 79 5 80 5 Meter Functions a With the 1450 TB attenuation set at 44 dB change the oscillator to 315 Hz Adjust the 1310 output for a 96 dB reading on the 1933 panel meter b Set 1933 PLAT SLOW a XN The meter must read within 0 1 dB of 96 dB Set 1933 SLOW OUT FLAT sow The meter must again read within 0 1 dB of 96 dB d Set 1310 Frequency DIM w v 5 awb Frequency Range 20 Hz 200 Hz 1933 se FLAT SLOW s s s s MN Adjust the 1310 output for a 96 dB reading on the meter Set 1933 SLOW pou uo x IMP 4 e s x o 5 amp The meter must read within 0 7 dB of 96 dB f Set 1933 PEAK IMP 1450 Attenuation WU UR RS The meter must read within 0 5 dB of 96 dB D c Output a Set 1933 IP 2 2 x um IMP 1450 Attenuation 1310 Frequency Dial 10 Frequency Range 200 Hz 2 kHz b Connect an 1807 Mil
62. B level on right side panel knob The overall ranges 10 130 20 140 and 30 150 dB are deter mined by the MAX MIKE dB knob left side panel 2 Indicates condition of battery when BAT CHECK button is depressed 3 Indicates calibration condition Full Scale when SOURCE top panel and MAX MIKE dB left side panel are at CAL and the octave band center frequency is 1 kHz 2 A B C FLAT 4 interlocked latching pushbuttons Selects A B or C weighting characteristic or Flat response 5 Hz or EXT 100 kHz when instrument is in WEIGHTING mode buttons 3 Octave Band 11 position drum indicator driven Indicates geometric center frequency of the selected octave filters Weighting with BAND switch knob on right and indicates when instrument is in WEIGHTING mode Marked Indicator side panel from left to right 31 5 Hz 63 Hz 125 Hz 250 Hz 500 Hz 1 kHz 2 kHz 4 kHz 8 kHz 16 kHz and weighting 1 2 INTRODUCTION meee Table 1 1 cont CONTROLS AND INDICATORS Fig 1 1 Ref Name 4 BAT CHECK button 5 BAND switch 6 ON OFF button 7 dB LEVEL 8 METER IMP SLOW buttons 9 OVERLOAD indicator 10 IMPULSE PK IMPACT 11 Figure 1 2 Top surface of 1933 shown with cover open for ac cess to controls The microphone mast 1 in unit installed is shown in stowed position The in microphone in its storage socket is at lower right SOURCE CAL MANUAL OVERRIDE NONE Description Latchin
63. EENS SOUND LEVEL CALIBRATOR TRIPOD DATA RECORDER POWER SUPPLY AND CHARGER Dummy Microphone Table 1 5 ACCESSORIES AVAILABLE Description Alkaline Energizer C cells 4 required Burgess AL1 Eveready E93 Mallory MN1400 or equivalent 4 required Flat Random Incidence Response 1 inch Electret Condenser 1 2 inch Electret Condenser 1 inch Ceramic 1 2 inch Ceramic Flat Perpendicular Response 1 inch Electret Condenser 1 2 inch Electret Condenser Microphone extension cable 60 ft Miniature phone plug to 1933 microphone mast Miniature phone plug to double banana plug Miniature phone plug to BNC Miniature phone plug to standard phone plug Miniature phone plug to standard phone jack Miniature phone plug to special double banana plug for Simpson 2745 recorder For 1 2 in microphone set of 4 For 1 inch microphone set of 4 Provides a precise sound pressure level at five ANSI preferred frequencies Thread mounts 20 to back of 1933 Two channel two track magnetic tape recorder using the Philips Cassette format Provides for line operation of 1933 and for charging NICAD batteries supplied with Power Supply and Charger 35 pF BNC 460 60 INTRODUCTION 1 5 Part Number 1933 9600 4270 1110 1933 2200 1962 9601 or 9602 1962 3200 1961 9601 or 9602 Part Number 1961 9601 1962 9601 166
64. Electric Corp Boston Mass Hardware Products Co Reading Penn 19602 Continental Wire Corp York Penn 17405 ITT Cannon Electric Inc Salem Mass Gerber Mfg Co Mishawaka Ind Johanson Mfg Co Boonton N J 07005 Augat Inc Attleboro Mass 02703 Chandler Co Wethersfield Conn 06109 Dale Electronics Inc Columbus Nebr Elco Corp Willow Grove Penn General Instruments Inc Dallas Texas Mephisto Tool Co Inc Hudson N Y 12534 Honeywell Inc Freeport Electra Insui Corp Woodside L I N Y E G amp G Boston Mass Ampex Corp Redwood City Calif 94063 Sylvania Elect Prods Inc Woburn Mass amp Mfg Co of Penn Inc Ramey Penn Cramer Products Co New York N Y 10013 Raytheon Co Components Div Quincy Mass Tung Sol Electric Inc Newark N J Weston Instruments Inc Archibald Penn 18403 Dickson Co Chicago III 60619 Atlas Industrial Corp Brooklyn N H Garde Mfg Co Cumberland 1 Quality Components Inc St Mary s Penn Alco Electronics Mfg Co Lawrence Mass Continental Connector Corp Woodside N Y Vitramon Inc Bridgeport Conn Methode Mfg Co Chicago III General Electric Co Schenectady N Y Anaconda Amer Brass Co Torrington Conn Hi Q Div of Aerovox Corp Orlean N Y Texas Instruments Inc Dallas Texas 75209 Thordarson Meissner Mt Carmel 111 Microwave Associates Inc Burlington Mass Amphenol Corp Janesville Wisc 53545 Military Standards Models I
65. ION DISTORTION METER RANGE 0 3 MODE AUTOMATIC Null the 334 A and measure distortion to be less than 0 2 4 6 12 Detector Dynamics Fast Slow Impulse Dynamics Make the test setup shown in Figure 4 6 GR776 C SYNC OUT REAR GR 1310 GR 274 NQ GR 274 NQ Figure 4 6 Setup for fast slow and impulse dynamics check 4 12 SERVICE OSCILLOSCOPE GR1450 TB a Set controls as follows 1310 Frequency Dial 200 Hz 2 Frequency Range 1450 FASOnUSDOR z o0 u e e o 1396 TRIGGER LEVEL SLOPE CYCLE COUNT PS o ox s NORN OUTPUT GN uu x om xo 1933 RANGE dB control os m DOM WEIGHTING BAND Control WEIGHTI SOURCE E e r vo s s amp NU The lamp behind CONT on P 1396 OUTPUT ON di should be on b Adjust the 1310 output for a reading of 126 dB or 1933 meter c Set 1396 OUTPUT ON a s p a xg With the oscilloscope Hiis cn the 1396 di just the 1396 OUTPUT ON vernier for an ON time of 0 25 v waveform on the oscilloscope for accurate adjustment 1933 meter should be reading fully down scale and then Maximum up scale reading should be from 124 to 126 dl GR 274 QBJ GR 776 C GR 1560 P9 PREAMP d Set 1396 OUTPUT ON CONT The meter should overshoot the 126 dB mark and re
66. M COMPONENTS WITH PREF MA ARE OM MAN FROME PREF C ARE on j 1 6 1367 ETCHED CABLE E wae 6 20 nee AU M host te oe f 8 A2 FALE et Vut 24 5 60 495 pee 5 CAL EACE OF AMO RST AND CONNECTION XO YXXWER 49 OR A XC IOSA FIR 12 44 DEN FACTORY ADIT ATS FOU FROVER Bias SF lt 0R 5004 73 _ lt 6096 6 24 2 4 70 724222 gt OCTANE FUSER 6 4 ATS mto 15 0 7P2 209624 5 51 51 26 51 C 3038 28 saor sr 3 D 2 C 5504 1 1 gt 25 24060 68 0 70 py Tt Sev z r geek 3 ZSEK ze we pg FISH Sape 12 USER 2534 2 r 2 EES 773 Ms WATE PIN t MC 3s 4 AM Ay ri oat 4144 499 47 3022 3 Le CONTROL ONES pos 13 X YE PININ HIE A MOTE PIN 5 es aA d T ARIE PEN 12 E EY sau seme 9 5 an gt 0604 mu QR 03 44 ANALYZING PROGRAMMARE lt 3 CAL BRATOR E BASE DIAGRAMS
67. REKE S590 b 1 1 ae 43 0 DITE E NEI 2 I 1 4 1 ma ie 0 0 ee 5 9 od E bL ae onda REPE E E 1 5 1 1 0 d 1 DEE ONG NUN Ti MUN Qu D e Um ome ew Gp The apparent loudness attributed to a sound varies not only with the sound pressure but also with the frequency or pitch of the sound addition the way it varies with frequency depends on the sound pressure This effect is taken into account by weighting networks designated B and C Responses A B and C selectively discriminate against low and high frequencies as prescribed in the SOUND LEVEL METER STANDARDS see Figure 2 1 Whenever one of these networks is used the reading obtained is the sound level and the weighting used must be specified For example the following are appropriate statements the A weighted sound level is 45 dB sound level 45 dB or SLA 45 dB The A weighted sound level is the one most widely used regardless of level A common practice is to assume A weighting if not otherwise specified It is recommended that
68. Sie gt E xs ATH 4 66 ERT 4 BOTTOM VIEWS 2 UM 24 474 iiic dpa ears Stee cea T 76 j DETECTOR CAL sheng SUBASSEMBLY SHOT 4 9 RMS 7 233 47 0 5 5 9 62 t Pa Q 3 4772 E Too Figure 5 5 Schematic diagram for 1933 analog circuits DIS zou C x Tas petto Parts amp Diaq 5 BOTTOM ERSE DIAGEANMIS EOTTOM VIEW 575706 BASE OIAGEAMS N O x Li i e re sje 4 e 5 22 3 977 5 0975 02 13 C UE 3 4 5 9 9 5 cl 8 3 10 141 SEND CENTER QIG LEAD DOWN TOWARD HEAT SINE 5230000000 Ute 969666 00660090604 0 6 8 68 Figure 5 4 etched circuit board assembly P N 1933 4730 NOTE Orientation Viewed from parts side Part number Refer to caption Symbolism Tone area part black ckt pattern parts side Pins Square pad in ckt pattern collector 1 1 cathode of diode end of capacitor ELECTRICAL PARTS LIST Fed Ref Des Description GR PartNo Mfg Code Mfg Part No Fed Stock No Etched Cable P N 1933 4740 CAPACITORS C2 Plastic 0136 uF 4862 1790 19396 PCR700 C6 Ceramic 1 pF 4400 2070 80183 5 1 GF 20 5910 083 6445 DIODES and CR2 1N
69. Z3 Resistor Network 24 Resistor Network 25 Resistor Network 26 Resistor Network Value to be selected by lab GR Part No 6099 6049 0360 6099 3165 6099 3475 6049 0110 6099 2565 6049 0110 6099 2565 6099 2625 6049 0108 6099 2625 6250 0909 6049 0104 6250 2100 6250 0909 6049 0104 6250 2100 5250 2150 6250 2588 6250 1229 6949 0105 6250 2100 6250 2768 6250 1475 6259 2190 6099 6475 6099 3105 6099 6475 6250 2845 6250 1634 6250 2562 6250 2348 6099 3105 6099 3245 6250 1909 6099 4515 6099 4305 6250 2180 6099 2105 6099 5475 6099 5225 6099 4515 6049 0114 6999 4105 6099 5105 6099 6099 2155 6099 1475 6099 3105 6099 2435 6099 3115 6099 4105 6099 5475 6099 2205 6099 3475 6250 1909 6250 1158 6099 1625 1933 0800 1933 0820 1933 0810 1933 0820 1933 0810 ELECTRICAL PARTS LIST cont Fed Mfg Code 24655 80294 75042 75042 24655 75042 24655 75042 75042 98474 75042 75042 98474 75042 75042 98474 75042 75042 75042 75042 98474 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 80294 75042 75042 24655 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 75042 24655 24655 24655 24655 24655 Mfg Part No 3329W BTS 16 5 BTS 47 5 6049 0110 BTS 5 6 57 6049 0110 BTS 5 6 kQ 5 6 2 59 59
70. ale fast enough to follow accurately the METER OUT DC voltage from the 1933 in the METER SLOW position and fairly well even with a fluctuating signal in the FAST and IMPULSE positions The following procedure is recommended to set up the level recorder to cover 50 dB range with a scale sensitivity of 5 dB cm 1 Connect the Y INPUT of the recorder to the METER OUT DC jack of the 1933 using a 1560 9675 cable This cable has 200 2 resistor molded in and a plug that fits the input terminals of the Simpson recorder The 200 9 resistor shunts the output of the analyzer to produce a lower voltage compatible with the recorder 2 Select a recorder sensitivity of 50 mV cm 3 Set the zero adjust on the recorder for zero pen deflection when the 1933 is turned off 2 12 OPERATION 4 Set the 1933 in its CAL mode with the meter indicating at full scale and adjust the sensitivity of the recorder for a pen deflection to 9096 of full scale 90 divisions when chart paper having 100 divisions is used 5 Now adjust the recorder zero control for a pen deflection to 8096 of full scale 80 divisions The recorder is now adjusted to produce a 50 dB range plot It will deflect to 40 dB 8096 of full scale when the 1933 is at full scale and to 50 dB when the 1933 is 10 dB above full scale The crest factor allowance when the recorder is at full scale is thus 10 dB Other recorders with similar sensitivity and writing speed to the Simpson 2745 s
71. anta Ana Calif 92702 Barber Colman Co Rockford Ill 61101 Barnes Mfg Co Mansfield O 44901 Wakefield Eng Inc Wakefield Mass 01880 Clevite Corp Cleveland 44110 Digitron Co Pasadena Calif Eagle Signal E W Bliss Co Baraboo Wisc Avnet Corp Culver City Calif 90230 Fairchild Camera Mountain View Calif Birtcher Corp No Los Angeles Calif Amer Semicond Arlington Hts 60004 Bodine Corp Bridgeport Conn 06605 Bodine Electric Co Chicago III 60618 Cont Device Corp Hawthorne Calif State Labs Inc N Y 10003 Borg Inst Delavan Wisc 53115 Vemaline Prod Co Franklin Lakes N J G E Semiconductor Buffalo N Y Star Tronics Inc Georgetown Mass 01830 Burgess Battery Co Freeport III Burndy Corp Norwalk Conn 06852 C T S of Berne Inc Berne Ind 46711 Chandler Evans Corp W Hartford Conn National Semiconductor Danbury Conn Crystalonics Cambridge Mass 02140 RCA Woodbridge N J Clarostat Mfg Co inc Dover 03820 Dickson Electronics Scottsdale Ariz Solitron Devices Tappan 10983 ITT Semiconductors W Palm Beach Fla Cornell Dubilier Electric Co Newark N J Corning Glass Works Corning N Y General Instrument Corp Hicksville Microdot Magnetics Inc Los Angeles Calif ITT Semiconductor Div Lawrence Mass Cutler Hammer Inc Milwaukee Wisc 53233 Spruce Pine Mica Co Spruce Pine N C Indiana General Corp Oglesby 61348 Singe
72. at the upper 20 dB above the output voltage corresponding to a full scale meter deflection dynamic range is figured by adding Because microphone is not used 20 dB to the number given Table 4 2 E METER READING DEVIATIONS Weighting 16 1 0 5 3 2 0 5 4 2 0 5 1 1 0 5 3 0 0 5 4 2 SERVICE 3 0 0 5 Relative Response dB Octave Band 31 5 Hz 1 kHz Table 4 3 TYPICAL OCTAVE BAND NOISE LEVELS IN ELECTRET dB LEVEL RANGE ALL PASS Octave Band Center Frequencies Hz FULL 20 Hz SCALE 20 kHz 31 5 63 125 250 500 1k 2k 4k 8k 16k 30 0 40 10 50 20 60 30 70 40 80 50 90 60 100 68 110 73 120 74 130 75 Levels not given in table are greater than 85 dB Table 4 4 TYPICAL OCTAVE BAND NOISE LEVELS 1 IN ELECTRET dB LEVEL ALL PASS t TERN RANGE Octave Band Center Frequencies Hz FULL 20 Hz 31 5 63 125 2k 4k SCALE Levels not given in table are greater than 85 dB NOTE Measured at the SIGNAL OUT AC jack in dB below the output voltage corresponding to a full scale meter deflection using a 1 2 electret condenser mike with typical sensitivity of 43 dB re 1 V N m and 35 pF capacitance NOTE Measured at the SIGNAL OUT AC jack in dB below the output voltage corresponding to a full scale meter deflection using a 1 electret con denser mike with typical sensitivity of 37 dB re 1 V N m and 100 pF
73. between J3 and J5 and between J2 and J4 Input Power Check Plug the power cord into the Variac and rotate the Variac control slowly to 115 V The Variac Wattmeter should read between 2 W Both BATTERY CHARGED and PWR line lights should be lighted Charge Current Check Make the following connections TOR LI ust Connect to Variac VUE g ouod x ww x 2 Set for 115 V out 1940 Power switch Line operation down Load See Fig 3 Connect load fixture to J1 and of 1940 J1 is side 1 2502 b Adjust load pot for 35 mA current Adjust RQ trickle charge to give a voltage of 7 1 V across J1 J4 c Rotate the load pot cw to give a reading of 5 5 V across J1 J4 The current should be between 190 210 mA Rotate the load pot fully cw The voltage should drop smoothly to 0 V and the current remain constant at 190 210 d Move the load fixture to J1 45 J1 is adjust variable pot for 35 mA The voltage should read 5 6 5 8 Adjust the load pot to give a reading of 4 5 V The ammeter should read 190 210 mA Rotate the load pot fully cw The voltage should drop smoothly to 0 V and the current remain constant at 190 210 mA f Rotate the load pot ccw until the BATTERY CHARGED light comes on The current should read 110 mA or less Adjust R9 if required Load Current Checks a Connect the load fixture Figure 3 to J1
74. capaci tance amplifier types using the Sallen and Key configura tion with three two pole i e resonant sections cascaded The weighting networks A B and C use much of the same circuitry as the octave band filters The normalized magni tude and phase responses of the filter are shown in Figures 2 2 and 2 3 respectively The TO EXT FILTER and FROM EXT FILTER jacks allow an external filter to be substi tuted for the internal weighting or octave band filter The automatic range control system is effective even for ternal networks 3 6 POWER The instrument operates from ordinary size ener gizers deriving about 20 hours of operation from four cells Optionally rechargeable cells may be used These charged from the 1940 Power Supply and Charger which also converts the analyzer to operate from the power line n 2 3 7 BLOCK DIAGRAM The signal is fed from the MIKE Figure 5 3 through the removable preamplifier to the input programmable ampli fier attenuator U1 This signal is then fed in turn to the BUFFER AMPLIFIER U2 octave filter and weighting network U3 U4 and U5 the analyzing programmable amplifier attenuator U14 the mean square detector and log converter the peak detector and finally the panel meter The peak or peak detectors U6 U8 and U7 09 are driven with signals from the outputs of the programmable amplifier attenuators These outputs are then fed through
75. ct the device to be driven to the SIGNAL OUT AC jack using a miniature phone plug the appropriate adaptor cable see paragraph 1 5 accessories available For maximum signal to noise ratio in the output signal adjust the dB LEVEL control so the maximum signal level drives the meter into the top half of its range The meter can be used to continuously monitor the level of the signal being amplified or set to monitor the batteries BAT CHECK When the meter is used to monitor the batteries the OVERLOAD lamp will continue to provide a warning when overload occurs The 600 Q output is DC coupled and will deliver an undistorted signal to any linear load impedance Table 2 4 DECIBELS RMS ACCELERATION IN CM SEC Pickup 54 eee Multiplier 0 1 1 0 10 10 ov 98 2108 4198 81 dB dB 121 1122 22 42 2 2 A2 1259 23 43 83 103 1413 24 44 84 104 1585 25 45 65 85 105 1778 26 46 66 86 106 1995 g 27 47 87 107 2239 1933 28 48 88 108 2512 indications mu 29 49 89 109 2818 50 90 110 3162 EM 3 51 91 111 3548 12 32 52 92 112 3981 13 33 53 93 113 A467 14 34 54 94 114 5012 15 35 55 95 115 5623 16 36 56 96 116 6310 17 37 57 97 117 7079 18 38 58 98 118 7943 wa 59 99 119 8913 D 40 60 100 120 000 eder the Rat o Value by the Multiplier above the dB column For example 65 48 reading it is 0 1778 10 1 778 cm Sec Theory Section 3 3
76. d d as necessary until the 1807 reads between 6 12 and 6 28 V Gain and Meter Adjustment Procedures Continue the test setup shown in Figure 4 1 a Continue the previous control settings except as follows 40 dB 1933 RANGE dB Control 130 dB 1450 Attenuation OdB b Center the main CAL Bot R2 on ite top edge of main board c Attach probe leads from the 1808 Ac Voltmeter to AT1 orange cable and AT2 signal ground and adjust the 1310 output for a reading of 0 5 V Refer to Figure 4 5 for location of AT1 and AT2 This should require approx imately 0 55 V out of the 1310 assuming 7 0 7 dB loss in the 1560 P9 dummy mike d Using the 1560 P79 cable attach the 1808 to the SIGNAL OUT AC jack and adjust R12 above AT1 for 0 5 V e Set 1450 Attenuation 13dB 1933 IMP elo A ox NM IMPULSE PEAK swith PEAK f Adjust R4 for a minimum reading on the 1933 panel meter This null should occur near midscale As a double check while adjusting R4 observe waveform at CR7 anode 1 OUT wee e RED 8 GREY COAXIAL CABLES 954 1933 11 Figure 4 3 Test points and adjustments for filter alignment 4 6 SERVICE junction CR7 and R15 See Figure 5 12 for waveforms The peaks should be of equal amplitude at the null point g Set 1450 Attenuation 20 dB 1933 IM OUT h Adjust the 1310 cutout 1933 n meter on the bottom scale line 110 dB Set 1450 Attenuati
77. diameter and P N 1962 3000 in diameter or perpendicular incidence response micro phones P N 1961 3100 1 in diameter and P N 1962 3100 diameter Typical frequency response and directional response characteristics are shown in Figures 3 1 3 2 3 3 3 4 for the 4 microphone types 3 3 OPTI RANGE SYSTEM Users of spectrum analyzers of any kind will recognize that these instruments invariably have two independently adjustable level range controls attenuators One control serves to change the gain of the amplifier ahead of the filter or weighting network and the other to change the gain of the amplifier which follows The two controls allow the greatest analysis range and signal to noise ratio dynamic range The 1933 Analyzer uses only a single level range control A control signal that is dependent on both the setting of this control and the peak level of the signal presented to the filters or weighting networks is used to set the gain of an THEORY 3 1 FREQUENCY Hz Typical random incidence response and tolerance pe PERPENDICULAR RESPONSE 4B 10 kHz FREQUENCY Hz Correction to be added algebraically to random incidence response Typical directional response of the microphone to find perpendicular and grazing incidence free field response Figure 3 1 Characteristics for 1 in electret microphone flat random incidence response 700
78. e certain that the main level range is within the acceptable range as stated above If it is then an OVER LOAD exists which can be eliminated by setting either the MANUAL OVERRIDE control or the main level range control to a higher range 2 4 CHECKING AND CHANGING BATTERIES Rated accuracy can be maintained only if the batteries supply more than a certain minimum voltage This voltage is indicated by the meter in the BAT CHECK mode There fore the batteries should be checked before checking cali bration or making measurements With the instrument ON press the BAT CHECK button and observe that the meter indicates above the battery mark If not slide off the battery cover on the bottom panel and replace the batteries being careful to observe polarity Use alkaline energizer C cells 4 required Burgess AL 1 Eveready E93 Mallory Mn 1400 or equivalent Alkaline energizers will provide about 20 hours continuous operation Ordinary flashlight batteries may also be used The operating time however will be substantially less NOTE Observe the usual precautions against the formation of ground loops when using external equipment 2 5 SIGNAL OUT AC JACK This jack allows the 1933 to be used as a preamplifier for a magnetic tape recorder a graphic level recorder or other devices may also be used for driving earphones This signal is taken from the output of the analyzing amplifier attenuator ahead of the detector It is an ampli
79. e level range control there is no possibility of getting an invalid meter indication through misuse of controls 2 It is unnecessary to make an all pass measurement of the signal before proceeding with an octave band analysis Measurement time is thus reduced If the level of the all pass signal should change during the analysis the automatic system will correct for this change a conventional manual system an increase in overall level after an octave band has been selected may overload early stages in the analyzer and produce an invalid meter indication 4 The output signal from the analyzer always has the maximum possible dynamic range for driving a magnetic tape recorder graphic level recorder or other device 5 The system guards against overload even when the weighting networks are being used Weighting net works are treated as filters so that high level low fre quency components in a signal whose A weighted level is being measured cannot overload front end stages In some cases for example when measuring a transient signal One available for measurement for only a few seconds whose band levels are known approximately it may be desirable to override the automatic system and 3 4 THEORY manually set the gain of the amplifier attenuator circuits to save the 4 5 settling time The MANUAL OVERRIDE control used in combination with the main level range control provides standard manual operation for the oc
80. e microphone and there fore charts are shown for the 1 and 1 2 electret con denser microphones and the 1 and 1 2 ceramic micro phones All charts apply for the typical microphone sen sitivity as given The lowest level that can be measured with a sound level meter is usually taken to be a level 5 dB above the absolute noise floor of the instrument Table 2 3 gives minimum levels according to this criterion for A B and C weighting FLAT and octave bands and for all four normally used microphones The internal noise levels of para 4 5 and those used here to determine the minimum measureable noise level are for a typical instrument the actual noise floor of any given instrument can be determined by replacing the microphone with a dummy source having a capacitance equal to that of the microphone The 1560 P9 Dummy Microphone has a capacitance of 35 pf and is thus suitable as a dummy source replacing the 1 2 electret condenser microphone The 1 electret condenser microphone should be replaced with a source capacitance of 125 pf and the 1 or 1 2 ceramic microphone should be replaced with a source capacitance of about 400 pf 2 17 USE OF ACCESSORIES A number of accessories are available for the Sound Level Meter and Analyzer and the various Sound Analysis Systems The purpose of each is described in the following The mini phone plugs 4270 1110 are used to make connection to the SIGNAL OUT AC jack the METER OUT DC jack
81. ear panels 4 2 INSTRUMENT RETURN Before returning an instrument to General Radio for service please ask our nearest office for a Returned Ma terial number Use of this number in correspondence and on a tag tied to the instrument will ensure proper handling and identification After the initial warranty period please avoid unnecessary delay by indicating how payment will be made i e send a purchase order number or for trans portation charges request O 0 For return shipment please use packaging that is ade quate to protect the instrument from damage i e equiva Table 4 1 lent to the original packaging Advice may be obtained from any GR office 4 3 SERVICEABILIT Y TEST Follow the procedures outlined below to determine that the gain of the 1933 is normal and that the weighting net works and filters are working properly 4 3 1 Test with Sound Level Calibrator The GR 1562 Sound Level Calibrator provides an easy means of testing the over all including the microphone gain weighting network response and filter response at five frequencies ranging from 250 Hz to 2000 Hz Place the calibrator set at 1 kHz over the microphone set the 1933 to FLAT WEIGHTING fast METER and turn it ON The 1933 should read 114 0 5 dB If it does not adjust it to 114 dB using the CAL screwdriver control located under the top cover Now check that the meter reading does not change by more than 0 3 dB for A B or C weighting
82. ect Find a Product to go to a convenient scrolling thumbnail catalog and then to detailed data sheets as desired or 2 Select STANDARDS DECADES STROBES for products formerly manufactured by GenRad General Radio or QuadTech Since 1976 IET labs has had a long standing commitment to conform the instruments and standards we offer to the customer s needs rather than to have the customer settle for what is available We devote our customer service and applications entirely to the customer s satisfaction in the quality standards test instru ments and calibration service we provide Combinations of functions special ranges ratings or accuracies e Replacement discontinued models from other manufacturers e Calibration and repair services NIST traceable e Compliant with ISO 9001 ISO 17025 ANSI Z540 1 1994 and MIL STD 45662A e Accuracy to 1 ppm TO e Resolution to 0 1 ppm e 1 Voltage to 20 kV Power to over 1000 W L 100 uH 100H Programmable IEEE 488 or BCD The World Standard in Metrology Featuring instruments formerly Since 1915 manufactured by Now continuing the GenRad tradition _ GenRad General Radio Quadlech IET Contents SPECIFICATIONS CONDENSED OPERATING INSTRUCTIONS INTRODUCTION SECTION 1 OPERATION SECTION 2 THEORY SECTION 3 SERVICE AND MAINTENANCE SECTION 4 PARTS AND DIAGRAMS SECTION 5 APPENDIX TYPE 1940 This instrument is capable of making s
83. educed by using a wind screen It is good practice to use a wind screen whenever making noise measurements out of doors The GR wind screens will reduce wind generated noise by about 20 dB for winds up to 25 mph with no serious 98 ERROR BE SUBTRACTED FROM TOTAL NOISE 4111 3 4 5 6 7 8 9 10 dB DIFFERENCE BETWEEN TOTAL NOISE amp BACKGROUND ALONE Figure 2 8 Background noise correction for sound measurements OPERATION 2 9 FREQUENCY RESPONSE ERROR CAUSED BY WIND SCREENS dB FREQUENCY Hz Figure 2 9 Effect of windscreens on microphone response effect on frequency response There is a slight loss of frequency response at high frequency as shown in figure 2 9 Since wind noise is concentrated at low frequencies using A weighting to attenuate the noise may help Also the octave bands above 500 Hz are less effected by wind noise than those below 2 15 3 Hum Pickup Magnetic Fields The maximum sensitivity of the 1933 to an external magnetic field is equivalent to 43 dB C when the applied field is 80 A m at 60 Hz Hum pickup is not normally a problem with the 1933 However when making measure ments near heavy electrical equipment a check may be made to see that there is no appreciable pickup of the mag netic field To make this check replace the microphone with the 1560 P9 dummy microphone or other shielded capacitor that has the same capacitance as the microphone being used With the dummy micropho
84. er than the full scale range indicated on the MANUAL OVERRIDE control Also the dB LEVEL control cannot usually be set to a full scale range more than 50 dB below that indicated by the MANUAL OVERRIDE control An exception is when the input signal has a low to moderate crest factor such as for example a square wave or sine wave signal If either the allowed maximum or minimum settings of the dB LEVEL control are exceeded the panel OVER LOAD lamp will light to warn the operator 2 12 USE OF SOURCE CONTROL The SOURCE control provides a means for conveniently using the Sound Level Meter and Analyzer with several sources including two microphones the 1935 Cassette Data Recorder and possibly an accelerometer The MIKE posi tions A and B normally select preset gains corresponding to those required for two microphones In the TAPE position 115 MAX dB value should be set at the colored dot corresponding to the dot adjacent to the microphone check block in the top cover 2 8 OPERATION the 1933 has a sensitivity of 0 5 V full scale when the dB LEVEL control is in its max cw position least sensitive meter range CAL activates the internal calibration system 2 13 DATA OUT CONNECTOR This is a nine pin miniature connector located on the left side panel of the 1933 It is used for interconnection with the 1935 Cassette Data Recorder When not in use it is capped Connection to the Data Recorder is by means of the coiled data cable 1935
85. ery check provided on 1933 Mechanical Small rugged hand held case with standard 0 25 20 threaded hole for tripod mounting DIMENSIONS wxhxd 6 25 x 9 x 3 in 159 x 229 x 76 mm WEIGHT 5 5 Ib 2 5 kg net 10 Ib 4 6 kg shipping Catalog Description Number 1933 Precision Sound Level Meter and Analyzer Conforms to IEC 179 and ANSI S1 4 1971 Type 1 With in and 1 in flat random incidence response Electret Condenser Microphone 1933 9700 With in flat random incidence response Electret Condenser Microphone only 1933 9701 1933 Precision Sound Level Meter and Analyzer Conforms to IEC 179 recommended for European countries With in and 1 in flat perpendicular incidence response Electret Condenser Microphones 1933 9702 With in flat perpendicular incidence response Electret Condenser Microphone only 1933 9703 Accessories Available Electret Condenser Microphones Flat random incidence response 1 in 1961 9601 Flat perpendicular incidence response 1 in 1961 9602 Flat random incidence response 1962 9601 Flat perpendicular incidence response in 1962 9602 Ceramic Microphone Cartridge and Adaptor 1 in 1560 9570 Earphone 1935 9601 Tripod 1560 9590 Cables Microphone extension cable 60 ft 1933 9601 Miniature phone plug to 1933 microphone mast 1933 9602 Miniature phone plug to double banana plug 1560 9677 Miniature phone plug to standard phone plug 1560 9678 Miniature phone plug to BNC 1560 9679 Windscreens
86. etector provides a peak measurement The FAST rms detector is used for steady or varying sound levels where meter fluctuations do not exceed 3 dB or where the detector is required to follow fast changes in level such as in automobile or aircraft pass by measure ments The slow rms detector has a longer averaging time characteristic than FAST The response is approximately that of an RC circuit with a time constant of 0 5 seconds When the signal is of sufficient duration to allow the meter pointer time to settle or for a time varying signal if level does not change too quickly vs time this characteristic will give a more accurate result than FAST The impulse detector is used for impulsive noises such as drop hammers or punch presses This characteristic is specified in the current draft supplement to IEC Publica tion 179 and gives a better approximation of subjective loudness for this type signal than does the rms characteris tic The Peak Impact detector is used to measure the absolute peak level of a signal The measurement of peak level is required by the Walsh Healey and the Occupational Safety and Health Act When both the METER SLOW and METER IMP buttons on the front panel are in their normal out position the 1933 has a FAST response To select SLOW depress the SLOW button To select IMPULSE or IMPACT PEAK set the slide switch or the right side panel to the appropriate position and depress the IMP button on the fron
87. expressly in lieu of and excludes all other warranties expressed or implied including the warranties of merchantability and fitness for a particular purpose and all other obligations or liabilities on our part including liability for consequential damages resulting from product failure or other causes No person firm or corporation is authorized to assume for us any other liability in connection with the sale of any product Condensed Operating Instructions a Lift the top cover install the desired microphone and extend the microphone mast to its full length b Set the MANUAL OVERRIDE control under top cover to AUTO Push in the knurled MAX MIKE dB control left side panel and turn it to the position indicated by the chart inside the top cover The proper setting is given adjacent to the serial number of the microphone being used The serial number of the micro phone is marked on the ring which is visible inside the threaded end When the 10 dB Attenuator is used with the 1 2 inch mike its serial number governs c Push the ON OFF button front panel to turn the instrument on and then the BAT CHECK button The meter should indicate above the BATTERY mark Again oress and then release the BAT CHECK button to return the instrument to normal operation d Use the dB LEVEL control lower major control on right side panel to align the CAL arrows on the MIKE dB control left side panel Select the 1 kHz octave band using t
88. f Figure 4 1 a Set the controls as follows 1310 FREQUENCY 1 kHz 1450 TB Attenuation 70 dB f 2f 1 11 f 11 f gt 19 dB down gt 70 dB down Hz Hz 18 75 63 2 86 346 5 31 5 126 5 73 693 63 250 11 38 1375 125 500 22 75 2750 250 1000 45 5 5500 500 2000 90 9 11 000 1000 4000 181 8 22 000 2000 8000 364 44 000 4000 16 000 727 88 000 8000 32 000 gt 62dB gt 62 98 at 2 kHz at 128 kHz 1 8 8 X HP 334 A FUNCTION Voltmeter METER RANGE 01 1933 RANGE Control 80 dB full scale WEIGHTING BAND Control 1 kHz Band b Connect 334 A to the signal out AC jack AJ4 with patch cord 1560 P79 Adjust the 1310 output for a 0 dB reading on the HP 334 A c Slowly sweep the 1310 oscillator dial to each side of 1 kHz and check that the peak to valley pass band ripple is less than 1 0 dB as read on HP 334 A d Adjust the 1310 frequency to 717 9 Hz and 1393 Hz using counter and note that the 3 dB points fall within 1 5 to 4 5 dB on the HP 334 A e Adjust the 1310 frequency dial to 500 Hz and 2 kHz Reduce the 1450 TB attenuator by 20 dB and note that the 334 A reads greater than 19 dB down Set 1450 back to 70 dB f Adjust the 1310 frequency to 90 0 Hz and 11 kHz Reduce 1450 TB attenuator by 70 dB and note that the HP 334 reads gt 70 dB down Refer to Table 4 7 and repeat steps a through f for each of the remaining octave bands to be within the stated limits 4 6 5 Uniformity of Level Octave Bands
89. for noise checks a Remove the input signal to the 1933 and short the input of the 1560 P9 Dummy Microphone with the BNC short b Set 1933 Range dB Control 40 dB WEIGHTING BAND Control WEIGHTING PLAS Ks w x wow wo SOURCE A The internal noise as 1933 meter must less than 36 c Measure the internal noise on other WEIGHTING and BAND ranges as follows 1933 1933 1933 Maximum 1933 Band Switch Weighting Band Range Meter Reading dB Weighting C 40 30 Weighting B 30 26 Weighting A 30 25 31 5 Hz 30 28 1 kHz 30 17 16 kHz 30 22 Overload Capacity and Distortion Check NOTE The following procedure requires the fabri cation of the filter circuit shown in Figure 4 4 a Retain the test set up of Figure 4 1 except substitute the 1309 oscillator in place of the 1310 b Connect the 100 k Hz low pass filter shown in Figure 4 4 between SIGNAL OUT AC jack and the input of the 334 A Distortion Analyzer via the GR 274 QBJ Adaptor Set 1450 Attenuation 20 dB T Noise levels apply when calibrated for a 43 dB microphone re 1 V N m BNC PLUG CONNECTOR N SHIELD 595 ALSO BOTH SHIELDS SHOULD BE GROUNDED TO CASE 1933 12 R10 AT1 AT2 FIGURE 5 11 FIGURE 5 6 R12 R7 R9 BACK R15 R18 U14 TP5 FIGURE 5 4 R47 R27 Figure 4 5 Interior of 1933 AT13 AT14 R37 R36 AT15 1933 RANGE dB Contro
90. g pushbutton with push release action Knob 11 position rotary switch Latching pushbutton with push release action Knob 11 position rotary switch 2 latching pushbuttons with push release action so both buttons can be released Lamp 2 position slide switch on side Preamplifier latch button Function Selects battery check mode Can be left in battery check position so battery condition can be monitored when instrument is used as preamplifier Selects one of 10 octave BAND center frequencies or WEIGHT ING mode Turns instrument ON when depressed Selects meter range as indicated on meter face IMP button selects impulse or peak meter characteristics depending on position of IMPULSE PEAK IMPACT switch on right side panel SLOW button selects slow meter characteristics When IMP and SLOW buttons are released the meter characteristic is fast Illuminates when an overload condition occurs indicating that the meter reading is invalid Also indicates in the MANUAL OVER RIDE mode when the dB level control has been incorrectly set Determines whether impulse response or peak response will be selected by the panel METER IMP button To remove preamplifier push button and pull unit off Table 1 2 TOP PANEL CONTROLS AND CONNECTOR Description 4 position rotary switch Recessed screwdriver control 7 position rotary switch Microphone Preamplifier and Extendible Mast Function Select
91. he 1807 Dc Millivoltmeter from AT15 to AT14 gnd on detector board This voltage should read 9 0 2 V e Connect the oscilloscope probe to AT42 on the main board to the left of transformer T1 Connect oscilloscope ground to the shield around the power supply f Observe the waveform at AT42 as shown in Figure 5 10 This waveform should be stable and its frequency approximately 300 kHz Bias Adjustment of U1 and U14 a Remove the input signal to the 1933 and short the 1560 P9 with a BNC short BIAS RESISTOR CONNECTED HERE EE Sn 01 1 12 2 9 o U14 9V 1 5 2 1 RANGE dB WEIGHTING BAND 1933 10 Figure 4 2 Power supply bias adjustment diagram b Set the 1933 controls as follows MIKE dB control 130 RANGE dB Control 80 dB full scale MANUAL OVERRIDE Sw 80 dB red dot SOURCE amp Connect the 1807 Dc to 3 of U1 voltmeter ground to power supply shield The bias voltage should measure 0 30 mV d Change the MANUAL OVERRIDE setting to 130 opposite red dot e Connect the 1807 to pin 3 of U14 Voltmeter ground to power supply shield The bias voltage should measure 0 30 mV If the above bias voltage tolerances for U1 and 014 not be met the following procedure should be followed a Remove the existing bias resistor Refer to diagram in Figure 4 2 b Determine the measured vo
92. he BAND control upper major control on right side panel and set the SOURCE control under top cover to CAL The meter should read at full scale indicating that the instrument is in calibration and ready for use If it does not the reading may be adjusted using the CAL screwdriver control located on the top panel under the top cover e Set the SOURCE control to A or B as indicated by the cover chart adjacent to the serial number of the micro phone in use and the instrument is ready for operation f Select WEIGHTING using the BAND contro and push the desired WEIGHTING button A B C or FLAT on the front panel Adjust the dB LEVEL control for an on scale meter deflection and read the meter g To measure an octave band level select the desired band using the BAND control adjust the dB LEVEL control for an on scale meter deflection and read the meter h The meter characteristic is normally at FAST may be set to SLOW by pressing the METER SLOW button on the front panel To select IMPULSE or PEAK IMPACT check that the slide switch on the right side panel is set to the appropriate position and then push the METER IMP button on the front panel Note that the SLOW and IMP buttons are not interlocked so that one must be released before the other can be depressed Introduction Section 1 1 1 PURPOSE 1 1 1 2 DESCRIPTION E ox we yga ow 1 3 CONTROLS CONNECTORS AND INDICATORS 1 1 1 4 ACCESSORIES SUPPLIED
93. hen turn the knurled knob Place the 1562 Calibrator set at 1 kHz over the microphone Set the BAND control to WEIGHTING and the dB LEVEL control for the 120 dB full scale range Depress the C but ton and adjust the appropriate gain preset control for a meter indication of 114 dB 2 9 PROXIMITY EFFECTS OF CASE AND OBSERVER Every effort has been made to make the 1933 a self contained precision sound measuring instrument The extendible mast and swivel mounting for the microphone and preamplifier make it possible to avoid in most cases the necessity of using an extension cable and tripod to remove the microphone from proximity to the instrument case and observer To achieve most accurate results always where practical follow these simple rules 1 Extend the mast to its full length where it will lock in position 2 Stand so the sound source is to your left 3 When using a random incidence microphone supplied with 1933 9700 9701 set the preamplifier to 20 When using a perpendicular incidence microphone set the pream plifier to 90 Hold the microphone away from yourself and other large objects and direct the mast not the micro phone at an angle perpendicular to a line connecting you and the sound source Figures 2 5 and 2 6 show the small error that may be introduced by the presence of the instrument case and observer when these rules are followed Error curves are given for the 20 preamplifier position and for
94. ing range RE SPONSE Fast slow absolute peak and impulse per 1 179 amendment pushbutton selected Precise rms detection for signals with lt 20 dB crest factor at full scale crest factor capacity greater below full scale OVERLOAD Signal peaks monitored at 2 critical points to provide positive panel lamp warning RANGING Auto matic system OPTI RANGE maximizes analyzing range and signal to noise ratio for each level range control setting manual control provides override Filters WEIGHTING A B C and flat pushbutton selected OCTAVE BANDS 10 manually selected with 3 5 1 dB atten uation at nominal cutoff gt 18 dB attenuation at and 2X center frequency gt 70 dB ultimate attenuation EXTERNAL FILTERS can be substituted for internal weighting networks and octave band filters connect to 2 miniature phone jacks Input 1 in electret condenser microphone with flat response random perpendicular incidence mounted with detachable preamplifier on 12 in extendible mast or on 10 ft extension cable supplied on 60 ft cable available Input can also be from tape recorder INPUT IMPEDANCE 2 G amp lt 3 pF Output SIGNAL OUTPUT 0 5 V rms behind 6002 corresponding to full scale meter deflection any load permissible RANGE CODE Contact closure provides sound level meter range information to 1935 Cassette Data Recorder DETECTED OUTPUT 4 5 V dc be hind 4 5 kQ corresponding to full scale mete
95. itch upper knob right side for the 1 kHz BAND and press the ON OFF button b Set dB LEVEL control lower knob right side for a meter range of 120 dB full scale c Set the frequency of the 1562 Sound Level Calibrator to 1000 Hz and place it over the microphone on the 1933 using the appropriate coupler adaptor d The meter should read 114 dB 0 5 If it does not adjust the CAL screwdriver control located on the top panel under the top cover until meter reads 114 dB If desired check the 1933 meter readings at other frequencies Select the BAND corresponding to the fre quency setting of the 1562 Alternately the BAND switch can be set to WEIGHTING and the FLAT button de pressed The dB levels observed on the 1933 meter should be within a few tenths of a decibel of the level observed in step d Note No warm up time is required beyond that for the meter needle to stabilize OPERATION 2 1 2 2 AUTOMATIC OPERATION 2 2 1 Selection of Weighting Characteristic Sound pressure which is the small variation in atmos pheric pressure caused by a sound or noise is measured in terms of newtons per square meter N m Sound pressure is usually expressed as a sound pressure level with respect to a reference sound pressure The sound pressure level SPL is expressed in decibels and for airborne sounds the reference pressure is 20 micronewtons per square meter 20uN m The definition
96. just the PULSE AMPLITUDE control red to produce a reading of 130 dB on the 1933 meter each time a pulse is injected meter must go fully down scale between pulses c Set 1340 PULSE DURATION Range X 100 us Adjust the PULSE DURATION variable control to pro duce a pulse of 200 us duration on the oscilloscope Do IMPACT GR 776B BNC Tee TEK P6011 1560 9 PRE AMP OSCILLOSCOPE Figure 4 7 Setup for peak dynamics check SERVICE 4 13 not adjust the PULSE AMPLITUDE CONTROL A single pulse of 200 us duration should produce a reading between 128 and 130 dB 4 6 13 Amplifier Crest Factor Capacity Check a Retain the test set up of Figure 4 1 and set the con trols as follows 1310 Frequency Dial gt Frequency Range 200 Hz 2 kHz Output Level s s xo M 1450 Attenuation 25 dB 1933 RANGE dB Control 120 dB full scale WEIGHTING Band Control WEIGHTING FLAT Pushbuttons 3 IN SLOW IMP OUT SOURCE dw PEAK IMP 20 s IMP b Adjust the 1310 output level for full scale on the 1933 panel meter Connect the scope to the SIG OUT AC jack AJ 4 c Step the 1450 TB attenuator down in 1 dB steps and Observe on scope the point above full scale at which output just begins to clip The final 1450 indication must be less than 8 dB 4 6 14 Opti Range Check a Use the same setup as Figure 4
97. l 12098 WEIGHTING BAND Control WEIGHTING PLAT i x sige gor s Go SOURCE s wow 2 MIKES 1309 FREQUENCY kHz OUTPUT 2 0V on 1808 334 A FUNCTION s a m VOLTMETER METER RANGE dM d Adjust R7 Mike adjust on rear of main board for 20 dB meter reading full scale This sets the gain for O dB microphone Note the dB reading on the 334 A ter Set 1450 Attenuation mi e w 908 334 METER RANGE 2 y s s a Check that the 334 A meter now reads between 17 7 to 18 3 dB above that noted in step d Observe this output with the oscilloscope to verify that there is no waveform clipping f Set 1450 Attenuation 3 20dB 334 A MEIER RANGE a i wow w VM 1309 A EREOUENGCY i s xw s Note the dB reading on the 334 A meter g Set 1450 Attenuation 1008 SERVICE 4 1 334 METER RANGE ox BM Check that the 334 A meter now 11 dB above that noted step 1 h Set 1309 FREQUENCY 1 kHz 1933 RANGE dB Control 130 dB SOURCE TAPE 1450 5 n ov o po wo vU 334 FUNCTION SET LEVEL METER RANGE 10096 Set the 1309 output for a full scale the 1933 meter and adjust the 334 A SENSITIVITY controls for a full scale reading i Set 334 A FUNCT
98. l at which the overload light goes on 4 6 16 Manual Override MAX dB Check a Use the same setup as Figure 4 1 and set the controls as follows 1310 Frequency Dial a s s a m 410 Frequency Range 200 Hz 2 kHz Output Leewal c w a amp M 1450 Attenuation 5008 1933 RANGE dB Control 80 dB full scale WEIGHTING BAND Control 1 kHz BAND b Adjust the 1310 oscillator output level for a full scale reading on the 1933 panel meter c Switch the MANUAL OVERRIDE control through each of its other six positions 80 through 130 using the red dot as an indicator The meter reading must stay the same for each setting and the OVERLOAD light must not be on at any setting except briefly during switching d Set 1933 RANGE dB Control 130 MANUAL OVERRIDE 130 red dot The OVERLOAD light must be off and the meter fully down scale e Set the 1933 MANUAL OVERRIDE to each position 80 through 120 at red dot The OVERLOAD light should be on in all positions and the meter fully down scale f Set the MANUAL OVERRIDE to AUTO max ccw The OVERLOAD light should be off 4 6 17 Data Out Check This section checks the data available at the DATA OUT jack this output is normally used in conjunction with the GR 1935 Cassette Data Recorder Refer to the figure below for pin locations O A O C 4 el Figure 4 8 Data Out jack a Measure the
99. livoltmeter to the d c output jack AJ 3 on the 1933 Adjust the 1310 output for full scale on the 1933 panel meter c The 1807 must read between 4 3 4 7 V Readjust the 1310 output for exactly 4 5 V on the 1807 Refer to the table below and check that the 1807 reads within the stated tolerances PEAK 47 dB 40 dB 1450 TB 1807 De Millivoltmeter 40 dB 4 5 V set 60 dB 2 5 50 mV 80 dB 0 5 V 100 mV 23 dB 6 2 V 50 mV 4 6 9 Weighting Check Use the same setup as in Figure 4 1 a Set the controls as follows 1310 Frequency Dial s s a s u 10 Frequency Range 200 Hz 2 kHz La u x ow 1450 TB Attenuation 60 dB 1933 RANGE dB Control 90 dB full scale WEIGHTING BAND Control WEIGHTING Pushbuttons PLAT m o 4 z X SLOW 4 w x IN b Adjust the 1310 output for an 80 dB reading on the 1933 panel meter Check the FLAT response according to the table below Keep the 1310 oscillator output level con stant throughout the test Use GR274 QBJ adaptor with 1933 P79 cable 1310 1450 TB 1933 1 kHz 60 dB 80 dB 5 Hz 54 0 57 0 dB 80 dB 100 kHz 54 61 dB 80 dB c Reset the controls as follows 1310 oscillator 1 kHz 1450 TB Attenuation 60 dB 1933 Pushbutton C x x IN d Adjust the 1310 output level for an 80 dB reference reading on the 1933 panel meter keep the 1310 output constant throughout the tests e Depress pushbutton B on
100. loss or change in calibration when a cable is used To install a cable remove the preamplifier by depressing the connector latch small button visible through hole at connector end of preampli fier with a pencil or other pointed object and pulling the preamplifier straight out Still longer cables can be used at reduced levels and fre quencies The length depends upon the capacitance of the cable used Approximately 1 mA peak is available from the preamplifier for driving a cable SOUND Wy SOURCE 1933 ANALYZER Figure 2 5 Error introduced by presence of instrument case and observer in sound field with preamplifier at 20 SOUND wey SOURCE Y 1933 ANALYZER Figure 2 6 Error introduced by presence of instrument case and observer in sound field with preamplifier at 90 1933 ANALYZER CJL 2s Figure 2 7 Error vs frequency introduced by instrument case alone in sound field with preamplifier at 07 OPERATION 2 7 2 11 USE OF MANUAL OVERRIDE CONTROL some cases for example when measuring a transient signal one available for measurement for only a few seconds whose band levels are known approximately it may be desirable to override the automatic system and manually set the gain of the amplifier attenuator circuits to save the 4second settling time A MANUAL OVER RIDE control used with the dB LEVEL control provides standard manual operation for the occasion when the auto matic sy
101. ltage gt 30 mV at pin to be positive or negative c If the voltage at pin 3 is negative select a resistor whose value may range from 4 to 47 that will bring the bias voltage within specifications d Install resistor between 9 V and pin 11 The existing slots for the bias resistor are shown in the diagram If voltage at pin 3 is positive select a resistor 4 to 47 9 that will bring bias voltage within specifications and install it between 9 V and pin 11 slots e Remove the BNC short and reconnect the input signal to the 1560 P9 4 6 3 Detector Board Adjustments Arrange the test set up shown in Figure 4 1 Initial Procedure a Set the controls as follows 1310 Frequency Dial 10 Frequency Range 200 Hz 2 kHz 1450 Attenuation 40 dB 1933 RANGE dB Control 6 4 s 10008 WEIGHTING BAND Control WEIGHTING MANUAL OVERRIDE MAX dB AUTO ww 4 3 we IMP SLOW OUT fast SOURCE TAPE b Connect the 1807 to the METER OUT DC jack and adjust the 1310 output for a reading of 4 5 V c Set 1450 Attenuation wx 2 308 If the 1807 reads between 6 12 and 6 28 V no adjustment of R36 is necessary If the 1807 reads more than 6 28 V turn R36 cw to read 6 20 V If the 1807 reads less than 6 12 V turn R36 ccw to read 6 20 V SERVICE 4 5 d Set 1450 Attenuation Adjust the 1310 output for a wading of 4 5 V e Repeat steps c an
102. measured at the Meter Out DC jack at six different levels on the 110 dB range The response is plotted for all four meter detector characteristics FAST SLOW IMPULSE and PEAK and includes the low frequen cy coupling effect of the 1962 microphone HHH HHH Ht 20 LAT ae X P E Fi E oY FIDA UI ETIE T Ssi ML 10 a oa 46 es ER d TI gt Eo o PLI 2 LEE E QON CUR gt o EIL gt T 30 LE 40 d zi HH EEE T 10 50 500 10K FREQUENCY Hz Figure 2 4 Comparative frequency responses of PEAK IMPULSE FAST and SLOW measurement modes of the 1933 Readings all taken at METER OUT DC jack OPERATION 2 5 2 7 USE OF FILTER JACKS The two miniature phone jacks closed circuit type on the left side panel marked TO EXT FILTER and FROM EXT FILTER can be used to substitute an external filter or weighting network for the internal ones To use the jacks set the BAND control to WEIGHTING and push the FLAT or ext button on the front panel The internal signal path is now
103. nc North Bergen N J Sealectro Corp Mamaroneck N Y 10544 Inc Burlingame Calif North Hills Electronics Inc Glen Cove N Y Metavac Inc Flushing N Y 11358 Transitron Electronics Corp Melrose Mass Varian Palo Alto Calif 94303 Atlee Corp Winchester Mass 01890 Delevan Electronics Corp E Aurora N Y U3 U4 U5 OCTAVE FILTER AND WEIGHTING REMOVABLE PREAMPLIFIER U1 INPUT PROGRAMMABLE AMPLIFIER ATTENUATOR 1933 4795 2D CONTROL MANUAL OVERI DE 53 06 08 PEAK OR PEAK DETECTOR U11 RESET COMPARATOR AUTORANGING LOGIC Ut3 COUNTER Q4 Q5 OVERLOAD COMPARATOR E CUN CLOCK ENABLE COMPARATOR U U9 PEAK OR PEAK DETECTOR ac If 52 Ul4 1933 4730 ANALYZING PROGRAMMABLE MEAN SQUARE DETECTOR PEAK PANEL AMPLIFIER ATTENUATOR AND LOG CONVERTER DETECTOR METER OUTPUT amb dads unda HENCE landi CLOSED FOR FAST amp SLOW 933 4710 OUTPUT DETECTED OUTPUT 600 0 DC NOTE HEAVY LINE IS MAIN SIGNAL PATH L GEM Gnd il _ 1933 PRECISION SOUND LEVEL METER AND ANALYZER BLOCK DIAGRAM 1933 8X Figure 5 3 Over all block diagram for 1933 Parts amp Diag 5 5 Ref Des Description CHASSIS MOUNTED PARTS CAPACITORS A Cl Tantalum Non Pola
104. nd lights the indicator lamp DS2 BATTERY CHARGED The regulator circuit for the line power source consists of integrated circuit U2 and transistors 06 and 07 and functions similarly to the charging supply The reference for this supply is derived from diode VR1 A voltage drop of 0 6 V across R11 limits the output current to approxi mately 250 mA Two diodes CR9 and 10 in series with the output to the 1933 give a voltage drop about equa to that of one battery cell SERVICE AND MAINTENANCE Table 1 TEST EQUIPMENT RECOMMENDED Instrument Requirements Recommended Wave Analyzer Continuous 20 Hz to 54 kHz GR 1900 Variac Nominal line voltage of autotransformer 120 V with meters for metered amps volts and watts Volt Ohmmeter Voltage range to 250 GR 1806 electronic ohms range to 10 9 Oscilloscope General purpose low frequency Tektronix type 547 1 A 1 plug in Ammeter Dc 0 500 mA Commercial Potentiometer Wirewound 0 250 ohms 10 W Commercial Or equivalgnt Ohmmeter Checks RX10K Figure 2 a With no power applied set BATT LINE to LINE and connect the ohmmeter side to 1 b Check that A J1 A J2 reads 20 kQ A J1 3 reads 1 MQ A J1 A J4 reads 1 MQ A J1 A J5 reads 1 MQ2 c Check that high side of line to low side reads 150 2 in 100 125 V 500 Q in 200 250 V positions of power switch A S2 d Set BATT LINE switch to BATT test for O ohms
105. ne installed the equivalent sound level due to hum should be 10dB or more lower than the sound level to be measured Changing the orientation of the instrument may help 2 15 4 High Sound Levels Microphonics At very high sound levels components or wiring in a sound level meter may vibrate and thereby produce an interfering noise The instrument is then said to be generating microphonics To test for microphonics replace the microphone with a 1560 P9 dummy microphone and observe whether the indicated level is less than the level with the microphone connected If the level in the band or with the weighting to be used is not at least 10 dB below the level with the microphone connected use a 10 or 60 preamplifier extension cable to allow the instrument to be removed from the high sound level area 2 15 5 Vibration The vibration sensitivity of the 1933 is primarily that of the microphone which is an equivalent maximum level of 83 dB for 1 g vibration 2 16 INTERNALLY GENERATED NOISE The dynamic range full scale to noise floor of the 2 10 OPERATION instrument is a function of the setting of the dB LEVEL control The noise charts in para 4 5 show typical internal ly generated noise levels in dB below full scale for each set tings of the dB LEVEL control when the instrument is set to C weighting as measured at the SIGNAL OUT AC jack by another octave band analyzer The dynamic range is also a function of the capacitance of th
106. ng by an amount equal and opposite to the sensitivity shift of the microphone The microphone temperature coefficient is shown on its calibration certifi cate an Overall Acoustical Calibration is performed the 1933 sound level readings will require no further correc tion However be sure to refer to the calibrator s instruc tions for temperature corrections if any to ts output 2 1 1 Internal Electrical Calibration The internal electrical calibrator checks the overall analyzer with the exception of the microphone at a frequency of 1kHz Use the dB LEVEL control lower major control on right side panel to align the CAL arrows on the MAX MIKE dB control left side panel Select the accuracy of the internal calibrator be 0 2 dB the temperature range between 10 C and 50 C 1 2 octave band using the BAND control upper major control on right side panel and set the SOURCE control under top cover to CAL Press the ON OFF button The meter should read at full scale indicating that the instru ment is in calibration and ready for use it does not the reading may be adjusted using the CAL screwdriver control located on the top panel under the top cover 2 1 2 Overall Acoustical Calibration Using 1562 The best method of checking calibration is with the 1562 Sound Level Calibrator which can check the micro phone as well as the electrical circuits at five frequencies a Set the BAND sw
107. o operate in a conventional manual mode with dual controls Figure 3 5 shows the gain combinations possible for the input programmable amplifier attenuator and the analyzing programmable amplifier attenuator for each setting of the level control The automatic system must follow the diagonal line labeled with the setting of the level control selected by the operator For example when the 80 dB range is selected the sum of the gains must equal 10 dB and there are six combinations possible to make up this Selection of the 30 dB or 130 dB range leaves only one possible gain combination THEORY 3 5 Service and Maintenance Section 4 4 1 GR FIELD SERVICE 4 1 4 2 INSTRUMENT RETURN 4 1 4 3 SERVICEABILITY TEST 4 1 4 4 OPENING THE CASE 4 2 4 5 INTERNAL NOISE LEVELS Us eo owe Up a 46 TEST AND CALIBRATION OF THE ANALYZER 45 4 7 FINAL CALIBRATION WITH MICROPHONES 445 4 1 GR FIELD SERVICE Our warranty at the front of this manual attests the quality of materials and workmanship in our products When difficulties do occur our service engineers will assist in any way possible If the difficulty cannot be eliminated by use of the following service instructions please write or phone the nearest GR service facility see back page giving full information of the trouble and of steps taken to remedy it Describe the instrument by type serial and ID numbers Refer to front and r
108. of SPL is SPL 20 log oa dB re 20 uN m where P is the root mean square rms sound pressure in N m for the sound in question For example if the sound pressure is 1 N m the corresponding sound pressure level SPL is 20 log 20 log 50000 94 dB Whenever level is included in the name of a quantity it can be expected that the value of the quantity will be given in decibels and a reference quantity is stated or implied The 1933 is calibrated in decibels relative to 20uN m as outlined above When the 1933 is in the FLAT mode the reading obtained is designated as the over all sound pres sure level or sound pressure level SPL 6 75 0 EET and LLL cl 4111 FC E LIIT FE MENS BE I D 1 2 1 Hee CENE oe a EN or E E ME EF 21 EEE E a a EASIER T Fr EF he 24 r Z cD cl LE ELL __ Il gt BA FU V E I 2O iT 4 anl Ud mL EL 9 3 fp CEPE NE EM E ULI RROD
109. on OdB The meter should now read full t 0 4 dB If the meter is more than 0 4 dB above full scale adjust R37 about halfway down to full scale If the meter is more than 0 4 dB below full scale adjust R37 about halfway up to full scale Set 1450 Attenuation 20 dB Adjust the 1310 output for reading again k Repeat step i and j as necessary until the meter read ing comes within 0 4 dB at full scale NOTE The 1310 output is always adjusted for a correct reading at bottom scale and R37 adjusted at full scale Set 1450 Attenuation OdB Adjust the 1310 output for ene of 0 V at t the SIGNAL OUT AC as read on the 1808 m Adjust R27 on the detector board for full scale read ing 130 dB on the 1933 meter n Connect the 1808 to EXT FILTER jack and measure the voltage to be 09 V 596 086 to 094 V Reconnect the voltmeter to SIGNAL OUT AC Set 1933 BAND Control 1 kHz Check that the meter reads within 0 4 dB of full scale if not perform the following filter alignment procedure Filter Alignment This procedure is to be followed only if the above check is not met the filter response check of para 4 6 4 is not met or a component is replaced in the filter section Use the same setup as in Figure 4 1 See Figure 4 3 for adjustment and test point locations a Set the controls as follows 1310 Frequency Dial 10 Frequency Range 200 Hz 2 kHz
110. or the FILTER jacks The screwdriver is for adjustment of the CAL control located in the top panel of the instrument or for adjust ment of the internal preset controls The 1933 9600 and 9601 10 ft and 60 ft Extension Cables are for use between the microphone preamplifier combination and the input connector on the mast of the 1933 They allow the microphone to be positioned remote ly from the instrument case and operator The MINE LABEL 1933 0150 is a self adhesive label stating that the 1933 has been approved for use by the U S Bureau of Mines It should be attached to the instrument as instructed in the protective instruction folder by those who intend to use the instrument where the Bureau of Mines approval is required The Dummy Microphone 1560 P9 is simply a capacitor which simulates the capacitance of the 1 2 inch electret condenser microphone It is used with the shorting cap in place to measure internal noise level The shorting cap can be removed to allow an electrical signal simulating the microphone source to be applied to the analyzer for testing and calibration When connected to the 1933 the loss in signal through the dummy mike is about 0 5 dB The Sound Level Calibrator 1562 is used to make an overall including the nicrophone calibration check on the analyzer t is provided with adaptors to fit the 1 inch and 1 2 inch microphones and generates a sound pressure level of 114 dB at five frequencies from 125
111. os crest factor such as those produced by typewriters and key punches The 1933 is especially suitable for such difficult measurements because it has a crest factor capacity of 20 dB at full scale on the meter proportionately higher below full scale in addition to the overload detection system The overload lamp will light when the peak level of the signal at any stage is high enough to overload that stage In addition when the analyzer is used in its manual mode it will also light if the main level range control is set to give a full scale range higher than or more than 50 dB lower than that indicated by the MANUAL OVERRIDE control When the analyzer is being used in its normal automatic mode set the level range control to a higher in dB range OPERATION 2 3 8 713 31 SAILV 134 RELATIVE FREQUENCY Figure 2 2 Normalized magnitude response of the octave band filter in the 1933 LELEEELEELEEEELELLEE TELLE ELEEE TEE EELELELLEE TEL T ELLE TL LT ARRAN mar sec nee os iii TE TE TE TT Wo TE 11 LT 5335930 L3IHS 3SVHd NORMALIZED FREQUENC Y Hz Figure 2 3 Normalized phase response of the octave band filter in the 1933 2 4 OPERATION when OVERLOAD is indicated In the manual mode check to b
112. ound level measurements re quired under Part 1910 95 Occupational Noise Exposure Dept of Labor of the Code of Federal Regulations Chap XVII of Title 29 36 F R 7006 Ref Federal Register Vol 36 No 105 May 29 1971 OGENERAL RADIO COMPANY 1973 Concord Massachusetts U S A 01742 Form 1933 0100 C November 1974 10 5556 Specifications This instrument carries U S Bureau of Mines approval for use in gassy coal mines Approval No 2G 2544 Specifications meet ANSI S1 4 1971 for Type 1 precision Sound Level Meters IEC 179 1965 for Precision Sound Level Meters IEC 123 1961 for Sound Level Meters ANSI 51 11 1966 for Octave Half Octave and Third Octave Band 0 Class 11 Filter Sets 225 1966 for Octave Half Octave and Third Octave Band Filters for the Analysis of Sound and Vibrations and Proposed 179 amendment for impulse measurement Level Range 10 to 130 dB re 20 uN m with 1 microphone 20 to 140 dB with in microphone in 10 dB steps Typical minimum measurable level with 1 in microphone 22 dBA with in microphone 31 dBA lower in octave bands Frequency 5 Hz to 100 kHz essentially flat response 10 octave bands with center frequencies from 31 5 Hz to 16 kHz plus A B and C weighting Display METER 20 dB scale linearly marked in dB and lower center and upper values automatically indicated on scale Highest accuracy obtained by using upper 10 dB as measur
113. ource provides for line operation of either the 1933 Precision Sound Level Meter and Analyzer or the 1935 Cassette Data Recorder complerely independent of the instrument s batteries t operates from line voltages be tween 100 125 and 200 250 V 50 400 Hz The charging source charges the batteries in either instrument APPENDIX Figure 1 Type 1940 Power Supply and charger shown with GR 1933 installed Catalog Description Number 1940 Power Supply and Charger 1340 9701 It is supplied with five rechargeable cells to replace the ordinary C cells supplied in the analyzer or recorder OPERATION There are no internal connections to make the instru ments simply plug into the 1940 and are supported at a convenient angle for bench top operation Figure 1 Dimensions for the unit are shown in Figure 2 4 219 Figure 2 AP 1 CIRCUIT DESCRIPTION See the schematic diagram Figure 5 for circuits referred to in the following description The regulator circuits for both sources are supplied from 3 common rectifier and filter capacitor circuit When the line voltage is applied the POWER LINE indicator lamp DS1 lights It is fed from a constant current source consist ing of transistor 08 diode CR11 and resistors R16 and R17 The regulator circuit for the charging source consists of integrated circuit 01 and transistors 04 and 05 is a FET that operates as a constant current source for diode VR1
114. ppears in the upper window on the front panel and set the dB LEVEL drum so that the numbers 110 120 130 appear in the meter scale windows Now care fully close the board by facing the front of the instrument 3 pulling forward on the dB LEVEL knob and pushing in tests Set the dB LEVEL control fully clockwise to its and slightly backward on the MAX MIKE dB control as it least sensitive range the BAND control counterclockwise emerges through its hole to WEIGHTING and the SOURCE control to TAPE Check To remove the front cover of the instrument and thus that the MANUAL OVERRIDE control is at AUTO select gain access to the calibration circuit located on the flexible FLAT WEIGHTING and turn the instrument ON The meter etched cable and the meter first remove two screws one should read 0 7 dB 0 3 dB below full scale at 129 3 0 3 recessed and located under the top cover at the front dB when the MAX MIKE dB control is set to 130 adjacent to the 1 2 in microphone storage hole and the Now check that the reading does not change by more other located on the floor of the battery compartment near than 0 3 dB for and C weighting or for the 1 kHz octave the front Then pull the front cover straight forward away band Check the deviation of the meter reading from its 1 from the instrument kHz reading for each weighting and for the 1 kHz 31 5 Hz To remove the meter first remove the four screws and 8 kHz octave bands as given in Table
115. r 2 3 pF 10 CONNECTORS Connector Connector Panel 1 thru 4 Miniature A J5 Mult Socket 9 Cont METER Meter ass y RESISTORS A R13 Comp 10 Q 15 Comp 510 Q SWITCHES A Sl Switch Toggle 2 Pos SPDT BATTERY A BT1 Battery 4 req d EARPHONES MICROPHONES 1 Dia Random 1 Dia Perpendicular 1 2 Random 1 2 Perpendicular GR Part No 4450 5803 1933 0400 1933 7090 4260 1110 4260 1110 5730 1933 6099 0105 6099 1515 7910 0460 8410 1500 1935 0410 1961 3000 1961 3100 1962 3000 1962 3100 ELECTRICAL PARTS LIST Fed Mfg Code 80183 24655 24655 24655 24655 24655 75042 75042 71744 09823 24655 24655 24655 24655 24655 Mfg Part No Fed Stock No 2 3 pF 10 V 1933 0400 1933 9091 4260 1110 4260 1110 5730 1933 BTS 10 Q 5 BTS 510 Q 5 23 021 109 1810 1935 0410 1961 3000 1961 3100 1962 3000 1962 3100 5905 809 8596 5905 801 8272 ELECTRICAL PARTS LIST Fed Ref Des Description GR Part Mfg Code Mfg Part No RRR Main Circuit Board P N 1933 4730 Cl and C2 Tantalum 4 7 pF 4450 4700 56289 1500465 0015 2 C3 Ceramic 20 pF 4404 0208 72982 831 20 pF 5 C4 Plastic 006355 pF 4862 1700 19396 700 C5 Plastic 06355 uF 4862 1860 19396 700 C6 Plastic 006355 uF 4862 1700 19396 PCR700 C7 and C8 Plastic 04264 4862 1820 19396 PCR700 C9 and C10 Plastic 0
116. r Co Diehl Div Somerville N J Voltronics Corp Hanover N J 07936 Illinois Tool Works Pakton Div Chicago IIl Computer Diode Corp S Fairlawn N J 07410 Cabtron Corp Chicago Ill 60622 LAC Electronics Horseheads N Y Electra Mfg Co Independence Kansas 67301 KMC Semiconductor Corp Long Valley N J 07853 Fafnir Bearing Co New Briton Conn UID Electronics Corp Hollywood Fla Avnet Electronics Corp Franklin Park 111 G E Schenectady N Y 12305 G E Electronics Comp Syracuse N Y G E Lamp Div Nela Park Cleveland Ohio General Radio W Concord Mass 01781 American Zettlet Inc Costa Mesa Calif Mfg Co Kenilworth N J Hoffman Electronics Corp El Monte Calif Beckman Instruments Inc Cedar Grove N J 07009 I B M Armonk New York Jensen Mfg Co Chicago Ill 60638 G E Comp Owensboro Ky 42301 Koehler Mfg Co Inc Marlboro Mass 01752 Constanta Co Mont 19 Que P R Mallory amp Co Inc Indianapolis Ind Marlin Rockwell Corp Jamestown Honeywell Inc Minneapolis Minn 55408 Muter Co Chicago III 60638 5 4 PARTS amp DIAGRAMS Code 42498 43991 49671 49956 53021 54715 56289 59730 59875 60399 61637 61864 63743 65083 65092 70485 70563 70903 71126 71279 71294 71400 71468 71590 71666 71729 71707 71744 71785 71823 72136 72259 72619 72699 72765 72825 72962 72982 73138 73445 73559 73690 73899 74193 74861 74868 74970
117. r deflection output is linear in dB at 0 1 V dB over 60 dB range 40 dB normal range plus 20 dB crest factor allowance any load permissible Calibration FACTORY Fully tested and calibrated to all specifi cations acoustical response and sensitivity are measured in a free field by comparison with a WE640AA Laboratory Standard Micro phone whose calibration is traceable to the U S National Bureau of Standards ON SITE Built in calibrator provides quick test of elec trical circuits GR 1562 Sound Level Calibrator is available for sim ple test of over all calibration including microphones Environmental Performance meets specifications of standards listed above TEMPERATURE 10 to 50 C operating 40 to 60 C storage with batteries removed HUMIDIT Y 0 to 9096 RH VIBRA TION AND MICROPHONICS Conform to applicable ANSI and IEC standards Noise Floor With 1 in electret mike 17 dBA with electret 26 dBA Both lower in octave band measurements Accessories Supplied Microphone attenuator tool kit 10 ft micro phone extension cable batteries Accessories Available 1940 Power Supply and Charger electret condenser microphones ceramic microphone cartridge and adaptor earphone tripod cables and windscreens Power 4 alkaline energizer C cells supplied provide 20 h tion 1940 Power Supply and Charger allows line operation of 1933 and includes rechargeable batteries and charging source Batt
118. readings on all noises be taken with all three weightings The three readings provide some indication of the frequency distribution of the noise If the level is essentially the same on all three networks the sound probably predominates in frequencies above 600 Hz If the level is greater on the C network than on the A and B networks by several decibels much of the noise is probably below 600 Hz Selection of the weighting mode is accomplished by turning the BAND switch knob on the right side panel to the WEIGHTING position and pressing the appropriate A B C or Flat button on the front panel 0 d BN i E ti ee tt 50K 100K A FREQUENCY Hz Figure 2 1 Frequency response characteristics for 1933 SLM with and without standard weighting networks Curves exclude the possible acoustical effects of a microphone and are based on a 35 pF source impedance 2 2 OPERATION 2 2 2 Meter Characteristic Three meter characteristics rms impulse and impact are available in the 1933 The rms detector has a FAST response and a SLOW response The impulse detector meets the draft IEC requirements and the impact d
119. response Also in a reverberant field there is little to be gained in accurately directing the mast and microphone 2 2 4 Making an Octave Band Analysis The 1933 has ten octave band filters with center frequencies ranging from 31 5 Hz to 16 kHz The magni tude and phase response characteristics of the filters are shown in Figures 2 2 and 2 3 Measuring octave band levels with the 1933 is as simple as measuring sound level The opti ranging system oper ates to ensure that the analyzer is never overloaded and it is unnecessary to make a FLAT all pass measurement before making the octave band analysis Simply select an octave band center frequency with the BAND control upper control on right side of case adjust the dB LEVEL control lower control on right side of case for an on scale meter deflection and read the meter The response is unaffected by weighting button position 2 3 OVERLOAD INDICATOR When the OVERLOAD lamp is lit lower right corner of meter meter readings are invalid The purpose of this lamp is to warn the operator when any of the circuits in the analyzer have been overloaded and also when the MANUAL OVERRIDE control has been used incorrectly It should be realized that a sound level meter that does not have an overload detection system may produce a meter indication that appears normal but is invalid because of overload This problem arises with impact sounds that have very high peak to rms rati
120. s and indicators are arranged conveniently and efficiently on the instrument A unique automatic system opti range eliminates the need for multiple concentric level controls attenuators normally required with all spectrum analyzers An ac signal output is provided for driving other equipment such as analyzers graphic level recorders or magnetic tape recorders A dc output proportional to the logarithm of the detected signal linear in decibels with a range of 60 dB is available for driving a recorder A multi pin data output connector provides range data and signal to the companion GR 1935 Cassette Data Recorder 1 3 CONTROLS CONNECTORS AND INDICATORS The controls connectors and indicators are identified in Figures 1 1 1 2 and 1 3 their functions are described in Tables 1 1 1 2 and 1 3 INTRODUCTION 1 1 N Tia or ie ia BAND 7 vorm BAND switch to wei ng B for oN CHECK SLOW i T Lem u 9 A Figure 1 1 Controls and indicators for 1933 Front view The microphone mast upper right is elevated but not extended Table 1 1 CONTROLS AND INDICATORS Fig 1 1 Name Name Description Function 1 Meter Face Recessed meter with dB scale adjust 1 Indicates dB levels ranging from 10 dB bottom scale to 150 dB able by means of dB LEVEL knob top scale Eleven of thirteen ranges are selected by the d
121. s gain of instrument to accomodate the source being used and selects internal calibrator Adjusts overall gain of instrument for calibration Selects normal AUTO operation and serves as manual input range control to set maximum input level Input connection from microphone INTRODUCTION 1 3 Table 1 3 CONTROLS AND CONNECTORS Yoni Fig 1 3 MI KE Ref Name Description Function 10 dB 1 EXTERNAL 5 flush mounted Provides connection to 1940 ATTENUATOR POWER Not banana plug Power Supply and Charger labeled receptacles See Appendix 2 DATA OUT Miniature 9 pin Provides connection to GR 1935 connector Cassette Data Recorder 3 TO EXT Miniature phone Connects to input of external FILTER jack filter minimum load impedance is 600 2 4 FROM EXT Miniature phone Connects to output of external FILTER jack filter input impedance 60 kN 5 MAX MIKE dB Concentric dial and Selects range of dB level con 3 knurled knob trol to match sensitivity of microphone in use Dot on rim of knurled knob aligns with MAX MIKE dB dot on inner dial according to information in table inside top cover For calibration aligns arrow C with arrow CAL by turning dB LEVEL control on right side 6 METER OUT Miniature phone Provides 4 5 volts dc output DC jack behind 4 5 kQ corresponding to full scale meter deflection 4 Linear in dB at 0 1 V dB over 60 dB range Any load resis 5 tance can be connected 7 SIGNAL OUT Miniature phone Provides ac signal outpu
122. stem is not appropriate When used in the automatic AUTO mode provided the OVERLOAD lamp is not lit the 1933 will produce a valid meter indication even during the 4 second settling time However during this period the dynamic range of the signal at the SIGNAL OUT AC jack and signal at DATA OUTPUT connector will generally not be as high as after the settling interval Given some knowledge of the expected overall level of a transient signal the settling interval can be avoided by use of the MANUAL OVERRIDE control For normal operation this control is set to AUTO max ccw For manual operation the control functions in exactly the same way as the input attenuator control on manual analyzer It is set in accordance with the expected maximum overall i e C weighted or FLAT level of the input signal Set the MANUAL OVERRIDE control to indicate a full scale level for the overall signal that is as high as or higher than the maximum overall level expected in the transient signal In some cases it may be possible to measure the overall C weighted or Flat level of a test signal in order to establish the correct setting of the MANUAL OVERRIDE control Now select the weighting network or filter band desired and adjust only the dB LEVEL control a meter full scale range that is at least as high or higher than the maximum level expected in the selected band Obviously the dB LEVEL control must not be set to a full scale range high
123. t of 0 5 6 AC jack volts rms behind 600 corres ponding to full scale meter de flection any load permissible 7 8 Battery connec 8 spring battery Makes connections to 4 C cells Figure 1 3 Side panel controls and indicator cover for DATA OUT jack in foreground 1 4 ACCESSORIES SUPPLIED tions TRIPOD mount not shown located on rear panel contacts 1 4 20 threaded bushing alkaline or rechargeable NICAD Sliding panel covers and holds batteries in place Permits mounting on a tripod 1 5 ACCESSORIES AVAILABLE The accessories supplied with the 1933 9700 9701 9702 and 9703 Precision Sound Level Meter and Analyzer are listed in Table 1 4 The accessories available for use with the 1933 9700 9701 9702 9703 Precision Sound Level Meter and Analyzer are listed in Table 1 5 1 4 INTRODUCTION Quantity Table 1 4 ACCESSORIES SUPPLIED Description Batteries alkaline C cells 10 ft EXTENSION CABLE preamplifier to mast Miniature phone plugs Switchcraft 850 PL Screwdriver for CAL adjustment Electret Condenser Microphone 2 10 dB attenuator for 1 2 Electret microphone Electret Condenser Microphone 1 with 1933 9700 and 1933 9702 only Microphone with 9601 suffix supplied with 1933 9700 and 1933 9701 Microphones with 9602 suffix supplied with 1933 9702 and 1933 9703 Name BATTERIES MICROPHONES MICROPHONES CABLES WINDSCR
124. t panel Note that the SLOW and IMP buttons are not interlocked so that one must be released before the other can be depressed 2 2 3 Extension of Mast and Selection of Microphone Angle The extendible mast arrangement permits the micro phone to be positioned about 12 inches from the instru ment case and thus avoids in most cases the necessity of using a cable and tripod To extend the mast open the top cover pull the microphone and preamplifier into an upright position and then withdraw the mast The mast is detented to lock in place when fully extended The microphone preamplifier assembly can be set at any angle over an arc of 180 CAUTION Do not attempt to rotate mast Collapse mast slowly When microphones having uniform random incidence response are used the assembly should normally be tilted to about 20 Figure 2 5 When microphones having uniform perpendicular incidence response are used the assembly should normally be set to a 90 position Figure 2 6 The mast not the assembly should then be directed at an angle perpendicular to a line connecting the source and the operator This angle will produce the least error in frequen cy response due to the presence of the instrument case and operator in the sound field see section 2 9 Indoors in a reverberant field a microphone having a uniform random incidence response will produce a more accurate result than a microphone having a uniform perpendicular incidence
125. the 1933 f Adjust the 1450 TB an 80 dB reference reading on the 1933 panel meter The 1450 TB must read between 59 8 60 2 dB g Depress pushbutton A on the 1933 h Adjust the 1450 TB for an 80 reference reading on the 1933 panel meter The 1450 must read 59 8 60 2 dB i Check the frequency characteristics of the C B and A weighting networks individually The 1450 limits are listed in the table below NOTE Before checking each network adjust the 1310 output set at 1 kHz for an 80 dB reference reading on the 1933 panel meter with the 1450 TB set to 60 dB 1450 TB Settings Network 1310 C B 1933 Level 1 kHz 60 dB 60 dB 60 dB set for 80 dB 31 5Hz 56 5 57 5 42 4 43 4 20 1 21 1 80dB 125 Hz 59 8 60 2 55 3 56 3 43 4 44 4 80dB 500 Hz 59 8 60 2 59 5 59 9 56 3 57 3 8048 8 kHz 56 5 57 5 56 6 57 6 58 4 59 4 80 dB 4 6 10 RANGE dB Control Check Use the same setup as in Figure 4 1 NOTE Connect the 1310 Oscillator 1900 Wave ana lyzer and the Counter two line power cords for this check to reduce ground loops a Set the controls as follows 1310 Oscillator Frequency Dial w s 10 Frequency Range 200 Hz 2 kHz O tg t 0981 i 6 s s s u SERVICE 4 9 1450 Attenuation 40 dB 1933 RANGE dB Control 90 dB full scale WEIGHTING BAND Control 1 kHz Pushbuttons wom 4 an IMP SLOW OUT fast 1900
126. truction sheet supplied with the accelerometer provides specifications and explains how it should be fastened Disregard instructions on use of the overall pick up system including the control box The low frequen cy limit when any of the above accelerometers are used is determined by the 1933 That is with the FLAT weighting the system including the accelerometer will respond uniformly down to about 5 Hz The upper frequency limit is determined by the resonant frequency of the accelerom eter It is usually taken to be about one half of the resonant frequency of the accelerometer and is given in Table 2 2 2 15 ENVIRONMENTAL EFFECTS 2 15 1 Background Noise Ideally when a noise source is measured the measure ment should determine only the direct air borne sound from the source with no appreciable contribution from noise produced by other sources This criterion is met practically when the background noise is 10 dB or more below the sound being measured If the background noise is not 10 dB below the sound being measured in any given band a correction can be applied to the total noise reading as determined by Figure 2 8 Take readings with the Sound Level Meter and Analyzer at the test position with and without the sound source to be measured operating The difference in readings determines the correction to be used For example if an octave band level reading with the sound source off background level is 77 dB and with the sound
127. turn Maximum overshoot should be from 126 1 to 127 1 dB on the meter e Set 1933 FLAT SLOW o e x o s ox ow sss 1396 OUTPUT OFF SEC OUTPUT ON EG Adjust the 1396 OUTPUT ON VERNIER for an ON time of 0 5s using the oscilloscope for adjustment The 1933 meter should again be going down scale and then up Maxi mum up scale reading should be from 121 to 123 dB f Set 1310 Frequency Dial w s s a 720 1933 SLOW FK s zs Xx OUT 4 v9 ox PEAK IMP IMP 1396 OUTPUT ON CONT OUTPUT OFF 10 SEC Adjust the 1310 output for a reading of 130 dB on the 1933 meter g Set 1396 OUTPUT ON 20 mSEC adjust with scope Maximum up scale reading should be from 124 9 to 127 9 GR 1340 h Set 1396 OUTPUT 5 mSEC adjust with scope OUTPUT OFF X 10 m SEC Adjust the 1396 OUTPUT OFF t time for a repetition rate of 20 ms using the oscilloscope NOTE Repetition rate is the time interval between the start of successive bursts The 1933 meter should now read from 123 9 to 126 4 dB Peak Dynamics Make the test setup shown in Figure 4 7 Set 1933 PEAK IMP 1340 PULSE PERIOD FREQ SINGLE PULSE PULSE DURATION Range X 10 ms PULSE OFFSET Both 0 Adjust the 1340 PULSE DURATION vatlabte conte to produce a 10 ms pulse using the oscilloscope for adjust ment Push the SINGLE PULSE button to produce a pulse each time b Ad
128. uch as the MFE M 12 recorder can also be used This recorder is AC operated and has a single chart speed GR Type 1522 DC Recorder The 1522 DC Recorder using the 1522 P1 Preamplifier is suitable for use with the 1933 Zero the recorder and connect the METER OUT DC jack of the 1933 to the 1522 P1 input with a 1560 9677 miniature phone plug to double banana plug cable Set the full scale range of the recorder to 5 V With the 1933 in the CAL mode reading full scale adjust the recorder deflection to 9096 of full scale 90 division when 100 division chart paper is used Reset the recorder zero adjust for an 8096 deflection The 5 inch chart should now cover a 50 dB range 10 dB inch corresponding to 1933 levels ranging from 10 dB above full scale 5 5 volts to 20 dB below bottom scale 0 5 volts The crest factor allowance of the system with the recorder at full scale is thus 10 dB 2 20 USING THE SOUND LFVEL METER AS A PREAMP Its wide frequency range 5 Hz to 100 kHz wide dynamic range high level output signal and low distortion make the 1933 ideal as a preamplifier for use in driving signal analyzers level recorder and magnetic tape recorders directly or through long interconnecting cables When it is used as a preamplifier weighting is normally set to FLAT or C if the signal is in the frequency range between 32 and 8 kHz Set the MANUAL OVERRIDE control to AUTO unless the signal is of short duration see paragraph 2 11 Conne
129. utlined area part gray ckt pattern if any parts side black other side Pins Square pad ckt pattern collector pin 1 cathode of diode or end of capacitor scatwom te E 0t pone mo INC VOCS SUSASSEMBLY 7140 9720 POMER SUPPLY BOARD v 244125 BASF DIAGRAMS TRANSISTORS views Sime a EK 45 2 i 8 CHARGED ne 6 2 4 7 IO 15 4 9 SOURCE 5 9 ME m GATE A NOTE COLLECTOR 4 EMITTER MAY BE SWAPPED DEPENDING UPON SUPPLIER A 28 2 3597 cri rp 7 200 ee 9 19 FARADA 8 APL AiWED v SEACE NOTES URS Lives SE e use 2 179 257 ECON SECTION NEAREST PANEL 6 529453 6 MOTTAS eOw Cow cos in in SWITCH NUMBERING CONNEC TION S Pant CONTHOL ___ COMA et war Testes Riz 5K cm WIS 5 sw 10 VJ 0 80 ore wre 5 1 gt 79 1955 BAT Pars 933 cR WH BR Re oe 236021
130. wer the 1933 from the 1940 supply connect the 1940 power cord to a power line and set the BATTERY PWR LINE switch to PWR LINE The PWR LINE lamp will light when the supply is connected to the power line Now simply operate the 1933 in the normal way While operating on PWR LINE the batteries will be charged by an independent charging supply The BATTERY CHARGED light will come on to indicate that the batteries are fully charged and are being maintained in that condition by trickle charging To charge the batteries only proceed as above but do not turn on the 1933 The 1933 may be operated from its batteries when mounted on the 1940 by setting the BATTERY PWR LINE switch on the 1940 to BATTERY One important feature of the 1940 Power Supply and Charger is that line power may be connected and disconnec ted by external means When power is disconnected the 1933 will cease to operate and will not drain its batteries 2 19 USING A D C RECORDER The METER OUT DC jack provides a DC signal linear in decibels for driving a DC recorder A DC recorder for use with a portable system such as the 1933 should be small lightweight and battery operated In addition it should have fast writing speed and a range of chart speeds so records of sound levels versus time and octave band levels vs frequency can be made The Simpson Model 2745 X Y Recorder is such a portable battery operated DC recorder Its writing speed is 20 cm sec 5 sec for full sc
131. yn Shakeproof 111 Took Works Elgin 60120 Sigma Instruments Inc S Braintree Mass Stackpole Carbon Co St Marys Penn Tinnerman Products Inc Cleveland Ohio RCA Rec Tube amp Semicond Harrison N J Wiremold Co Hartford Conn 06110 Zierick Mfg Co New Rochelle N Y Tektronix Inc Beaverton Ore 97005 Prestole Fastener Toledo Ohio Vickers Inc St Louis Mo Electronic Industries Assoc Washington D C Sprague Products Co No Adams Mass Motorola Inc Franklin Park 111 60131 Standard Oil Co Lafeyette Ind Bourns Inc Riverside Calif 92506 Sylvania Electric Products Inc N Y 10017 Air Filter Corp Milwaukee Wisc 53218 Hammarlund Co Inc New York N Y Beckman Instruments Inc Fullerton Calif Code 81030 81073 81143 81349 81350 81386 81483 81751 81831 81840 81860 82219 82273 82389 82647 82807 82877 83033 83186 83361 83587 83740 83781 84411 84835 84971 86577 86687 88140 88219 88419 88627 89482 89665 90201 90750 90952 91032 91146 91210 91293 91506 91598 91637 91662 91719 91916 91929 92519 92678 92739 93332 93618 93916 94144 94154 94271 94589 95076 95121 95146 95238 95275 95354 95412 95794 96214 96256 96341 96791 97684 98291 98474 98821 99111 99180 99313 99378 Manufacturer Pure Carbon Co St Marys Penn 15857 International Instrument Orange Conn Grayhill Inc LaGrange 60525 Isolantite Mfg Corp

1 - IET Labs, Inc.

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