Shure M267 User's Manual
Contents
1. GENERAL The Shure Model M267 is a microphone mixer remote amplifier specifically designed for professional applications The excellent performance versatility and features of this complete compact console make it an ideal choice for stu dio remote or sound reinforcement use and as an add on mixer for expanding existing facilities It is also ideally suited for use with audio and video tape recorders to provide multi ple microphone inputs Features Wide flat frequency response and extremely low dis tortion up to 418 dBm output e Extremely low noise and RF susceptibility e Four switchable microphone or line level balanced line inputs with individual gain controls and low frequency rolloff switches MUMETAL shielding on input transform ers e Feedback type input gain controls for maximum clip ping levels and dynamic range e Output switchable for line or microphone level e M Built in switchable peak limiter cuts output overload distortion adapts to power supply voltage e LED indicator shows limiter operation or overload with limiter defeated e Externally adjustable limiter threshold 4 to 18 dBm e VU meter calibrated for 4 and 8 dBm with range switch Illuminated with ac operation e Acor built in battery operation Noiseless automatic switchover to battery in case of ac line failure Battery test without program interruption e Front panel headphone level control and monitor jack drives almost any2. XLR Switchcraft Connector 3 Pin Male XLR Switchcraft Y3MPC Phone Jack Switchcraft L 1128PC Ferrite Bead Ring Panasonic Exc ELSA35 Meter 190 pA None Knob MIC 1 4 MASTER None Knobs PHONE None Cover Battery None 861628 Capacitor Electrolytic 5 uF 25V Sprague TVA 1303 MP8 MP9 pene End Cap None PL301 PL302 PL302 95A8010 m ee 0202 Q204 86A334 Q203 Q205 86A348 Q206 864335 0207 86 8302 R250 46A8016 R302 R306 46B8000 R310 R314 R317 46C8000 R322 46D8000 9101 5104 5588008 105 302 306 5588007 106 S107 301 5588001 905 8909 201 5548035 307 308 5548009 7201 7204 9588165 T205 51E235A T206 51A8021 U201 86B808A U202 86A8908 U203 86A811A U204 0205 86A811A U206 86A803 86B8930 U207 Lamp 6 3V 02A 6 3V 0 2A EE X Transistor NPN Transistor NPN Transistor PNP Transistor PNP Transistor PNP Potentiometer 100k Potentiometer 100k Potentiometer 200k Potentiometer 5k Switch Slide 3PDT Switch Slide DPDT Switch Slide DPDT Switch Slide DPDT 90CB2600 Switch Pushbutton SPDT Switch Slide 3PDT Transformer Input Transformer Output Transformer Power Integrated Circuit Quad Op Ampl Selected for NF Opto Isolator Integrated Circuit Dual Op Ampl Integrated Circuit Dual Op Ampl Integrated Cir
3. stereo or mono headphones output can be additional unbalanced line feed to drive a tape recorder or power amplifier Shure Brothers Incorporated 222 Hartrey Avenue Evanston IL 60202 3696 U S A Model M267 User Guide Lae e Direct mix bus for stacking units e Automatic muting prevents speaker damage during turn on and off e Lowdistortion high stability tone oscillator for line test and level checks e All connections phased Line output terminals phase indicated e Compact and lightweight with rugged abrasion resis tant case e Internally selectable 120 or 240 Vac 50 60 Hz opera tion e Underwriters Laboratories Listed and Canadian Stan dards Association listed as Certified SPECIFICATIONS Frequency Response 30 Hz to 20 000 Hz 2 dB Voltage Gain at 1 000 Hz Outputs terminated line 600 microphone 150 Q mix bus 3 3 kQ headphone 200 Q tip sleeve and ring sleeve OUTPUT Input Line Microphone Mix Bus Low Impedance 91 dB 41 dB 24 dB Microphone 150 Q Line 40 dB 9 dB 27 dB 58 5 Inputs IMPEDANCE LI Actual Input for Use Internal ES With Clipping Level Microphone LE to 32 dBV to 600 Q 5 dBV 25 mV to 0 56 V Line 66 20 dBV than10 kQ TENE Depending on input control setting 1999 Shure Brothers Incorporated 27 8376 SE Printed in U S A Outputs HMPEPANEES E a for Actual With Internal Clipping Level Micr
4. 0 215 218 861626 C216 C222 86A630 C221 C229 86N630 C223 865628 0209 86 415 0211 0214 0222 0223 0226 0229 0210 0217 864404 0230 0235 D218 D221 86A405 D301 201 80 159 F202 806380 J1 95C450 J2A B 90T2600 J101 J104 95B8011 J105 95B8012 3301 90BJ2600 L101 L113 80A365 M1 RKC170 95A8214 MP1 MP5 90A8028 MP6 90A8029 MP7 9048027 REPLACEMENT PARTS LIST REFERENCE PART COMMERCIAL DESIGNATION NUMBER DESCRIPTION ALTERNATE Jnescrnion EN Capacitor Electrolytic 250 uF 50 Sprague 501D227F063PR Capacitor Electrolytic 22 uF 6 3V Sprague 501 D226F01 6LL Capacitor Electrolytic 10 uF 25V Sprague TE 1204 Capacitor Electrolytic 68 uF 25V Sprague 501D686F025MN Capacitor Electrolytic 470 uF 35V Sprague 503D477F035QE Capacitor Electrolytic 5 uF 35V Sprague TE1303 Capacitor Electrolytic 22 uF 35V Mallory F226KM Capacitor Electrolytic 1 uF 50V Sprague TVA1300 Diode Silicon Computer 75V TI 1N4148 Silicon Rectifier 100V 1 2A Motorola 1N4002 Diode Germanium 30V RCA 1N48 1N60 Diode Light Emitting Generallnstrument 5075 Fuse Slow Blow 0 1 250V Littlefuse 313000 Se ries Fuse Time Lag 0 05A 250V Schurter034 3104 Jack Phono Switchcraft 3511A Connectors Binding Post None Connector 3 Pin Female
5. 0 Hz 1 596 or less THD Phantom Power 30 Vdc open circuit 3 3 series resistance input switches in MIC position only Operating Voltage Ac Operation 120 or 240 volts 10 50 60 Hz 9 5W internally switchablet Dc Operation 27 volts nominal at 15 mA typical no signal 18 mA typical at 0 VU 4 dBm output with headphone load 21 5 volts minimum Battery life approximately 20 hours with alkaline bat teries at 4 dBm output in continuous use three 9 volt batteries type NEDA 1604 Duracell MN1604 rec ommended Supplied wiredfor 120 Vac operation See Service section for 240 Vac operation Temperature Range Operating 189 to 579 C 0 to 135 Storage 29 to 71 C 20 to 160 F Dimensions See Figure 1 Li 3 um 68 8mm 2 23 32 in 6 3 1 4 in FIGURE 1 Weight Net 2 3 kg 5 Ib 2 oz Packaged 3 2 kg 7 Ib 2 oz Certifications Listed by Underwriters Laboratories Inc and listed by Canadian Standards Association as Certified CONTROLS AND CONNECTORS WARNING This apparatus must be earthed grounded The M267 power supply is energized when the unit is connected to an ac source disconnect mains power plug from supply when not in use Inputs The four inputs are professional three pin female XLR audio connectors located on the rear panel and designated INPUT 1 through INPUT 4 The inputs are balanced inter nal transformer MUMETAL shielded pin
6. NOHd SWHO 009 G20V01 INdLNO ANIT Hx Iv SWHO Os HONOSHL AGP EL DIN SNMOHS SNOllISOd SSHOLIMS Ty 3 Ov gaansval SASVLICA Tiv p BOvVLion BOVLIOA annoys QNnONo 2H toes LY ov d Lino SISSVHD OVA 21 500 9603 OWT SO O ddndans 384O0N3O GhoaWAS 9NIMOTM Od 3HL HUM 3Ssnad 1023 S AOoW3H 32unos IVA OGZ O12 921212345 BSIMASHLO SSSINA SLIM OL SuHOLSIS34 mv 2 v WONS N3HM SLOAN X _NINMOHS SHOLI2vdv 5 DILAIOY1LI3513 31512345 3SI M3HlO 6 37 HO HO SLIOA OS ONY NI Suoll2vdv5 TV i MS 385 Laro Pais LO X DIOSMY BIOIM 2 SANIT Me AEE YOM yy ro 380438 ATdd NMOHS F 838 F s32Nv43104 S3H2NI NI SNOISN3WIQ 17Y 935412345 3SIMU3HIO 931N 53 2 ddY INIMOTIOS IHL ONIMYMO 31Y28 LON OQ NNOHS SNOISN3WIO 360 3NU O Z5 amp veld L 2 DIN 50 1 LOdNt o Me AEE Vom j coed Em DESIGNATION Em C101 C209 C219 C227 C232 C115 p C201 C204 Es C205 C208 C210 86M630 212 213 86863
7. anel Kit The Model A268R Rack Panel Kit includes 19 in x 3 1 5 in 483 mm x 89 mm precut rack panel and necessary hardware for rack mounting the M267 with its cover in place and end caps removed ina standard 19 in 483 mm rack panel RKC169 Rack Panel Bracket Kit The Model RKC169 Rack Panel Bracket Kit enables owners of the Shure A68R Rack Panel Kit originally designed for the M67 and M68 Mixers to rack mount the M267 with the A68R SERVICE WARNING Voltages in this equpment are harzardous Refer servicing to qualified service personnel 240 Vac Operation To change the M267 operating voltage from 120 Vac to 240 Vac follow these steps 1 Disconnect the M267 from the ac line 2 Remove the end caps and cover 3 Locate the voltage selector switch S201 at the right rear of the main printed circuit board Figure 3 Move 0201 to the 240V position toward the front panel i wal d A T206 F20 Lrsdiesov 4 S201 240V WE 240 V WIRING FIGURE 3 4 Remove fuse F201 0 1A 250V time lag and replace it with the supplied fuse F202 0 05A 250V time lag Note that the F202 fuse holder is at right angles to the F201 fuse holder 5 Replace the ac line cord if necessary with one de signed for the 240 Vac source If the M267 is to be used outside the U S and Canada local regulations may require replacing the line cord with one having wire insu
8. cuit Dual Op Ampl Integrated Circuit Voltage Regulator Syivanias6 86 Er PE Motorola2N5210 Rohm 11592 Motorola2N5087 Rohm TIS93 MotorolaTIP30A None None None None None None None Switchcraft EPST PC1 Switchcraft 953 None None None None Raytheon RC4156N None Raytheon RC4559NB 86A806A Integrated Circuit Quad Comparator RaytheonLM339DB Raytheon RC4559NB Motorola MC1458C P1 NationalSemiconductor LM317AT W1 90A8045 Line Cord AC None Parts listed as RKC Kits should be ordered by that kit number
9. ed to pins 2 and 3 of each input connection Series current limiting resistance is 3 3 for each input When using other condenser micro phones with the M267 verify that the voltage and resis tance requirements are compatible Note that the phantom power cannot normally be ap plied to the inputs with the MIC LINE switches in the LINE position IMPORTANT Do notturn the PHANTOM switch on when using unbalanced low impedance microphones objec tionable hum will result Turn off the PHANTOM switch when condenser microphones are not being used Use only high quality cable Intermittent shorts between broken shield wires and balanced conductors will cause of fensive noise transients in the system BATTERY OPERATION AND EXTERNAL POWERING In addition to ac operation the M267 can be operated from an internal battery pack Current drain is typically 17 mA at 8 dBm output level and typically 15 mA at 4 dBm Battery power is recommended both for remote on loca tion operation and as an emergency backup source in case of failure of the ac power Access to the battery compartment is provided at the bottom of the chassis Three 9 volt alkaline batteries pow er the M267 at full rated output Use alkaline batteries for maximum life Duracell MN1604A or Eveready 522 are recommended Battery life is approximately 20 hours at 4 dBm continuos use Note that battery operation with phan tom power loads and high level headphone monitoring wil
10. l increase battery drain With batteries in the battery compartment the M267 will automatically and silently switch to battery operation should the ac voltage fall below a suitable level If the ac power fails completely the VU meter lamps will go out pro viding a visual indication of line failure Battery condition can be determined by using the BATT CHECK switch on the front panel Activate the BATT CHECK switch and observe the VU meter A new set of batteries will give about a 2 VU indication Battery condi tion is good if the reading is above 0 VU a lower reading means that new batteries are required for proper opera tion Note that the M267 power switch must be turned on to check battery condition Telephone Interconnection When using the M267 connected directly to a telephone line checkto see whether the local telephone company re quires an interface coupler between the M267 and the tele phone line If a coupler is required make certain the cou pler selected and the wiring arrangement are in compliance with the telephone company regulations Telephone Line Surge Protection When using the M267 connected directly to a telephone line subject to lightning induced voltage surges the follow ing commercially available part can be installed across the LINE OUT terminals to provide additional protection for output circuit components Metal Oxide Varistor General Electric Co Type No V22ZA1 ACCESSORIES A268R Rack P
11. lation colors as follows F201 Live or Earth or Hot Neutral Ground U S Canada Black White Green Europe Brown Blue Green Yellow 6 Replace the cover and end caps and mark the rear panel to reflect the new operating voltage PRINTED CIRUCIT BOARDS COMPONENT SIDE qii INPUT TRANSFORMERS T201 T204 a N 5 D jog 5 e EU oj 0 s TRANSISTOR LEAD CODES 2 o o N gt a a a 2 5 CY e or z D LRT 2 o o odo oan uo a aw i m a PI Po P3 PRIMARY 02 11 6908 d OO T 927 29 5 1 S3Nond Ara M As ATE get eee vooy H3LUAT1 Ni WV SVIGC 292 TAGOW oO T So2L BLOM qLO2A 1 8 P 1025 ADOEM 390 HEE 3902 peo 12523 I IAM ALZ IO 2012 WEE ri m 28 ONIdVaa NA O X 12950 OL 195 ZOES AINO 02 hava AVN 8 GAL BY SSOTWA SHILAW WHOSIW Qanocvaw Sa9evino 2v WOWIXYW oL 13 e33 431 ANY ANANI 353375 OL SWHO OO8 Q30vOo S3
12. ophone Any low imped 34 dB ance microphone 20 mV input Mix Bus 3 5 KQ 3 5 KQ 8 dBV 400 mV Head 8 2000 400 Q to 10 dBV phones 200 Q 3 8 3 V recommended Line 6000 1500 18 dBm 6 2 V Depending on level control setting Noise Equivalent Input Hum and Noise 126 dBV low im pedance microphone 150 O 20 20 000 Hz into a 600 Q load at full gain Output Noise 75 dBV master control fully counter clockwise 53 dBV master fully clockwise input con trols down 300 20 000 Hz Output Hum and Noise 70 dBV master control down 51 dBV master control up input controls down 20 20 000 Hz Distortion 0 35 or less THD from 30 to 20 000 Hz at 15 dBm output 0 5 or less IM distortion up to 15 dBm output level Common Mode Rejection 65 dB minimum with input of 20 dBV at 100 Hz Control Interaction Less than 1 dB with any control combination Overload and Shorting Protection Shorting the outputs even for prolonged periods will cause no damage microphone inputs will not be dam aged by signals up to 3 volts Lo Cut Filters 6 dB octave rolloff at 150 Hz Limiter Threshold 15 dBm line output level adjustable from 4 to 18 dBm Attack Time Recovery Time 500 msec typical 3 msec typical Peak Indicator Lights 6 dB below clipping or at onset of limiter action Headphone Output Clipping Level 3 16V 10 into 200 Q Tone Oscillator 1 00
13. s 2 and 3 are hot and pin 1 is ground For microphone operation the switches labeled LINE MIC directly above the input con nectors must be in the MIC position for line level inputs the switches must be in the LINE position For impedance clipping and operating signal levels refer to the SPECIFI CATIONS section Outputs The rear panel connector labeled OUTPUT is a profes sional three pin male XLR audio connector With the adja cent LINE MIC switch in the MIC position the OUTPUT connector is used to feed a low impedance microphone line or a low impedance microphone input With the LINE MIC switch in the LINE position the OUTPUT connector feeds the line level input of an amplifier tape recorder or another mixer The OUTPUT connector is a balanced out put with the LINE MIC switch in either position pin 1 is ground pins 2 and 3 are hot and the connector is in phase with the corresponding pins of the input connectors Therear panel binding post connector designated LINE OUTPUT is in parallel with the OUTPUT connector and can be used as aline level output feed simultaneously with the OUTPUT connector The terminals are numbered 2 and 3 and are in phase with the corresponding pins of the input connectors While the line outputs can be used to drive various impedance lines the VU meter is calibrated for use with a 600 Q line The line output transformer will operate properly with up to 100 mA dc in the line This feat
14. s IN operating the mixer output is limited to approximately 15dBm Increasing the individual or MASTER gain con trols will increase the average output and the amount of limiting The limiter threshold can be resetto any other out put between 4 and 18 dBm if desired With the limiter switched OUT and tone oscillator activated adjust INPUT 1 and MASTER level controls to produce an output 0 5 dB higher than desired Switch the limiter IN and set the LIM ITER THRESHOLD ADJUST control accessible though the bottom of the chassis for the desired level The front panel PEAK LED indicator shows limiter op eration with the limiter in and operates when program lev els approach overload with the limiter out The indicator is much faster than a meter and will be activated by the short est transient peak but it remains on long enough to provide easy recognition Low Cut Filters The low cut filters provide a low frequency rolloff to the response curve as shown in Figure 2 The filters are acti vated by the LO CUT IN OUT switch above each individual input gain control and can be used individually with each control to reduce wind noise or undesirable low frequency signals such as from condenser microphones or turntable rumble RELATIVE RESPONSE IN dB 20 20 50 100 200 500 1 000 FREQUENCY IN Hz LOW CUT FILTER ACTION FIGURE 2 Mix Bus Direct access to the mixing b
15. to battery The VU meter is connected on the primary side of the output transformer to assure protection from any dc level on a telephone line Headphones The headphone outlet appears at the front panel jack panel designated PHONES The two circuit phone jack will accommodate most stereo or mono headphones The output level is sufficient to provide high volume for use in noisy environments Note that the headphone output level is also high enough to use as an auxiliary unbalanced line feed to drive a tape deck or a power amplifier Thetip and ring connections of the headphone plugs are in phase with pin 3 of all input and output connectors and with the tip of the MIX BUS jack Tone Oscillator The highly stable low distortion tone oscillator provides for line test and level checks The oscillator is instantly ac tivated by the front panel INPUT 1 OSC 1 switch its level can then be controlled by the INPUT 1 gain control on the front panel The tone oscillator frequency is 1 000 Hz and the signal appears on both the line and microphone out puts as well as the headphone and mix bus connectors The oscillator should be switched off INPUT 1 position when not in use Phantom Power The rear panel PHANTOM OFF ON switch controls the application of phantom power for condenser microphones such as the Shure SM81 and SM87A to all inputs With the switch on and the rear panel MIC LINE switches in the MIC positions 30 Vdc is appli
16. ure permits the use of standard dialed up telephone lines with dc across them Since a slight distortion increase may occur at high output levels with maximum dc current operation with the VU RANGE switch at 4 dBm is recommended Input Gain Controls The front panel controls designated 1 through 4 are the in dividual active gain controls for correspondingly numbered inputs Note that the input connectors are located on the rear panel directly behind their corresponding gain control The controls set the preamplifier gain and provide preamplifier output attenuation As the gain is reduced the preamplifier input clipping level is increased for that channel Input control 1 serves an additional function as the level control for the tone oscillator when the INPUT 1 OCS 1 switch is in the OSC 1 position IMPORTANT For optimum signal to noise ratio the indi vidual input controls should be operated at as high a set ting as possible consistent with maintaining adequate control range and input clipping level Master Gain Control The front panel control designated MASTER is the mas ter gain control which sets the overall output level of the mixed sources including signals applied to the MIX BUS input Limiter The front panel LIMITER IN OUT switch turns on a fast acting peak responding limiter circuit that cuts overload distortion during loud program intervals without affecting normal program levels When the LIMITER switch i
17. us is provided through the rear panel MIX BUS phono pin jack This provision is made primarily to facilitate stacking or multing M267s to achieve additional input capacity without losing any inputs With two M267s for example the two mixing buses are di rectly connected providing two independent master gain controls and two isolated line amplifiers with eight individu ally controlled inputs Since the buses are directly paral leled a 6 dB drop in gain will occur and the master or input controls must be increased to compensate Noise specifi cations are not adversely affected by this interconnection Mix bus interconnection can also be made with other Shure mixers such as the M268 FP42 etc VU Meter The VU meter is factory calibrated for use with a 600 Q terminated line The VU RANGE switch on the rear panel selects either a 4 or 8 dBm output at 0 VU meter indica tion This switch changes the meter indication but does not change the actual output level Microphone output levels are 50 dB below line output The 4 range is recom mended for normal use to provide approximately 14 dB of headroom from operating level to clipping level The VU meter is illuminated by two No 86 lamps operat ing well under their normal ratings for a life expectancy of greater than 10 000 hours The lamps are only lit during ac operation Consequently the illumination serves as a visual alarm if the ac is interrupted and the unit has switched
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