Hafler 9270 User's Manual
Contents
1. HOME AUDIO COMPONENTS Series 9180 9270 Power Amplifier Series 9180 9270 NOTICE IMPORTANT SAFETY INFORMATION The lightning flash with arrowhead symbol within an equilateral triangle is intended to alert the user to the presence of uninsulated dangerous voltage within the products enclosure that may RISK OF ELECTRIC SHOCK be of sufficient magnitude to constitute a risk of DO NOT OPEN electric shock to persons 10 WARNING TO PREVENT FIRE OR The exclamation point within an equilateral triangle is intended to alert the user of the SHOCK HAZARD DO NOT EXPOSE THIS presence of important operating and mainte EQUIPMENT TO RAIN OR MOISTURE aa 2 7 READ INSTRUCTIONS All the safety and operating instructions of your Hafler equipment should be read before power is applied to the equipment RETAIN OWNERS MANUAL These safety and operating instructions should be retained for future reference HEED WARNINGS All warnings on the equipment and in the operating instructions are important and should be followed FOLLOW INSTRUCTIONS All operating and use instructions are important and should be followed HEAT The equipment should be kept away from areas of high temperature such as heater vents radiators stoves ovens fireplaces etc VENTILATION The equipment should be used in an area suitable for proper ventilation Care should be taken not to impede airflow in and around the cabinet Do not moun2. SSH 719T SSH 719T 9270 Only SSH 719T SSH 724 SS 101A SS 207 SS 215 SS 215 SSH 618 SS 163 SS 163 SS 162 SS 212 SS 212 SS 162 SS 162 SS 212 SS 212 SS 162 SSH 609 CCH 232 CCH 231 CC 568 CCH 245 CCH 246 CCH 247 CCH 233 SWH 510 SWH 152G Gray SWH 152B Black TT 9180 TT 9270 9180 9270 FS 005 9180 FS 007 9270 FS 005 9180 FS 007 9270 500789 9180 100 120V 800488 9180 220 240V 501088 9270 100 120V FS 005SB 9270 220 240V LEFT LEFT MONO LEFT MONO GAIN LEFT CH INPUT AMPLIFIER OUTPUT MONO STEREO SWITCH O RIGHT OUTPUT V RIGHT RIGHT CH RIGHT AMPLIFIER Mi INPUT p gt THERMAL SOFT PROTECTION TURN SYSTEM SYSTEM SUPPLY 9180 9270 FUNCTIONAL BLOCK DIAGRAM 515 A 908 48 BET ree D Hin IN 18 ila i ye INA as nt z svia 16 99 305 1 3 0 003 R23 SEE ruse CHART HV C13 0 1 Q18 2SK1057 25 1057 FDH400 42 LEFT OUTPUT 1 5245 CR6 1N4148 14 0 1 7 5 Por lt SEE FUSE CHART CIRCUIT SCHEMATIC DIAGRAM RMSED 1 1 13 91 CR202 1N5245 TO R CH TO L CH R202 NOTE 3 UNLESS SPECIFIED OTHERWISE L 1 ALL RESISTORS
3. RMP 4 0475 R24 R124 47 5 RMP 4 0475 R5 R105 66 1 RMP 4 0681 R25 R125 221 RMP 4 2210 R6 R106 47 5 RMP 4 0475 R26 R126 475 RMP 4 4750 R7 R107 47 5 RMP 4 0475 R27 R127 475 RMP 4 4750 R8 R108 1K RMP 4 1001 R28 R128 475 RMP 4 4750 R9 R109 1K RMPN 1001 R29 R129 221 RMP 4 2210 R10 R110 6 61K RMP 4 6811 R30 R130 221 RMP 4 2210 475 4 4752 R31 R131 221 RMP 4 2210 R12 R112 243 RMP 4 2431 R32 R132 475K RMP 4 4753 12 DESIGNATOR VALUE R33 R133 47 5K R34 R134 33 2K R35 R135 47 5K R36 R136 100 R37 R137 100 R38 R138 100 R39 R139 100 R40 R140 15K R41 R141 10 5W Wirewound R42 R142 1K R43 R143 4 75M R44 R144 1M R45 R145 1M R46 R146 1M R47 R147 1M R201 75 5 W Carbon R202 75 5 W Carbon R203 100 204 10 205 18 2 206 332K R207 18 2K R208 332K R209 1K R210 68 1K R211 33 2K R212 33 2K R213 47 5K VR1 VR101 50K Volume P1 P101 1 K Trim ALL CAPACITORS IN MICROFARADS unless specified otherwise DESIGNATOR VALUE C1 C101 330p Polypropylene 330p Polystyrene C2 0102 10p Mica 8p Polystyrene C3 C103 0 1 Polycarbonate 0 1 Polypropylene 4 104 220 NP Electrolytic C5 C105 0 001 Polypropylene 0 001 Polystyrene 06 106 0 001 Polypropylene 0 001 Polystyrene C7 C107 220p Polypropylene 220p Polystyrene 08 0108 01 Polycarbonate 01 Polypropylene 9 109 01 Polycarbonate 0 1 Polypropylene C10 C110 0 1 Polycarbonate 0 1 Polypropylene 100 Electrolyti
4. an attempt to mate to a two wire ungrounded receptacle use a grounding adaptor with the grounding tab or wire suitably connected to earth ground 1 11 12 14 15 NON USE PERIODS During periods of extended non use the power cord should be unplugged from the power source CLEANING The equipment should be cleaned only as detailed in the operating instructions OBJECT AND LIQUID ENTRY Care should be taken so that objects and or liquids such as cleaning fluids or beverages are not spilled into the enclosure of the equipment DAMAGE REQUIRING SERVICE Hafler equipment should be serviced by qualified service personnel when A The power supply cord or plug has been damaged or B Objects have fallen or liquid has been spilled into the equipment or C The equipment has been exposed to rain or D The equipment does not appear to operate normally or exhibits a marked change in performance or E The equipment has been dropped or the enclosure has been damaged SERVICING The user should not attempt to service the eguipment beyond that which is described in the operating instructions All other service should be referred to gualified service personnel 16 CARTS AND STANDS The eguipment should be used with carts or stands only of sufficient strength and stability for the use intended An equipment and cart combination should be moved with care Quick stops and starts excessive force and uneven surfaces may cause the e
5. and should be earth grounded The ground adaptor s should cure this grounding problem as well WARNING The use of ground adaptors with the ground tab or wire of the adaptor disconnected will eliminate the safety feature of the grounded power cord This safety feature is intended to reduce the risk of electric shock should an internal fault in the equipment result in an electrically live chassis Therefore this method of ground isolation should be employed only when absolutely necessary rather than as a general practice When using a ground adaptor for isolation make sure that the power cord plug is inserted into the receptacle in the same orientation as if no adaptor were present to maintain the same hot neutral polarity SPECIAL NOTE ON VIDEO CABLE GROUNDS As mentioned above the ground conductor of cable service and antenna feeds should be connected to earth ground Often however due to long feed lengths especially in apartment distribution systems this ground will be of poor quality and could be a source of noise This interference is usually characterized by a high frequency noise rather than a hum or a buzz If such interference is experienced a separate earth ground connection should be made from the cable outlet nearest the audio video equipment to a known good earth ground If ground loops exist due to potential differences in the interconnects in rack mounted systems then it is advisable to isolate the preamplifi
6. around the unit Operation at very high power levels into low impedances for extended periods may overheat the amplifier but no damage will occur due to the Thermal Protection System In the Mono Mode some additional consideration is required when driving low impedances When a stereo amplifier is converted bridged into a single channel mono amplifier each half of the bridged amplifier sees only half of the loudspeaker s load impedance For example when driving an 8 ohm load in the Mono Mode each channel is actually loaded to 4 ohms Therefore little advantage is gained when attempting to drive 4 ohm loads 2 ohms per channel in the Mono Mode because of the reduced power available at extremely low impedances It is usually better to use a stereo amplifier of higher power rating rather than two bridged amplifiers of lower power when driving low impedances The 9180 9270 Amplifier is equipped with a simple means to adjust the AC line voltage rating for 100 120 220 or 240 volts AC 50 60 Hz The configuration is labelled above the power cord connector If the amplifier will be used in a location that requires a different line voltage use the following procedure to change the configuration Review the modification instructions before attempting this procedure If any doubts exist about one s ability to change the line voltage it is advisable that the procedure be conducted by a qualified technician WARNING UNPLUG THE UNIT FROM
7. specified otherwise Power Rating 9180 9270 Rated THD Full Power Bandwidth Signal to Noise Ratio Input Impedance Input Sensitivity 9180 9270 Damping Factor Rate Controls Inputs outputs Power Consumption Size Weight 9180 9270 105 watts per channel 8 ohms 150 watts per channel 4 ohms 300 watts mono 8 ohms 135 watts per channel 8 ohms 200 watts per channel 4 ohms 400 watts mono 8 ohms less than 0 025 typically 0 005 at 1 kHz 0 3 Hz to 116 kHz greater than 100 dB unweighted 47 000 ohms 1 4 volts RMS 1 6 volts RMS 300 to 1 kHz 200 to 10 kHz 50 ViuS Power Switch Left Right Gain Controls Mono Stereo Switch Right and Left Mono RCA jacks Right Left and Mono 5 Way Binding Posts 100 watts quiescent 1200 watts maximum 17 W x 12 5 D w3 5 H excluding feet faceplate 17 or 19 W 43 20m W 31 7cm D x 8 9cm H faceplate 43 2cm or 48 3cm W excluding feet 33 bs 15 kg net 35 5 15 9 kg net INSTALLATION RACK MOUNTING VENTILATION PLACEMENT VOLIAGE The 9180 9270 Amplifier is supplied in either a 17 Black Version or a 19 Silver Version The 19 model has rackmounting holes provided for installation in equipment racks The holes are on standard EIA spacings Due to conflict with adjacent equipment it may be advisable to remove the four rubber feet from the bottom of the unit The feet may be removed from the ou
8. 8 0118 019 0119 020 0120 021 0121 Q22 Q122 Q201 TS1 152 TRM CR1 CR101 CR2 CR102 CR3 CR103 CR4 CR104 CR5 CR105 CR6 CR106 CR7 CR107 CR201 CR202 CR203 BR301 J1 J101 2 102 4201 4301 Swi 301 T301 FA F101 F2 F102 LINE FUSE VALUE 0 01 Polypropylene 0 01 Polypropylene 0 01 Polycarbonate 15000 Electrolytic 15000 Electrolytic 0 01 Ceramic 0 01 UL Approved 2SK163 Graded 2SK163 Graded 2SJ74 Graded 2SJ74 Graded N5550 N5550 N5401 N5401 N5401 N5550 N5415 N3440 N2222A N3440 N5415 2SK1057 2SK1057 2SK1057 2SJ161 2SJ161 2SJ161 2N7000 MPSA56 N N N Graded Graded Graded Graded Graded Graded LM393 Thermal Sensor Thermal Sensor Inrush Limitor FDH400 FDH400 1N4148 1N5245B 15V 1N5245B 15V 1N4148 1N4148 1N52458 15V 1N52458 15V 1N4148 Diode Bridge RCA Jack White RCA Jack Red 5 Way Binding Post AC Voltage Selector Header Housing Pins IEC Connector Stereo Mono Switch Power Switch Power Xformer Amp Amp Amp Amp Amp Slo Blo Amp Slo Blo Amp Slo Blo Amp Slo Blo OLO PART NUMBER CPP 103A CPP 103A CYV 103 CER 159ES CER 159ES CD I 03 20 CD 103A SSH614T SSH 614T SSH 617DT SSH 617DT SSH613 SSH 613 SSH 708 SSH 708 SSH 708 SSH 613 SSH 616 SSH 612 SSH 611 SSH612 SSH 616 SSH 717T SSH 717T 9270 Only SSH 717T
9. AC POWER BEFORE ATTEMPTING THIS PROCE DURE FAILURE TO DO SO CAN RESULT IN SEVERE ELECTRICAL SHOCK 1 Remove the top cover by removing the seven allen head screws three on each side one at rear center 2 Using the diagram Component Layout as a guide find the white Voltage Selector plug on the printed circuit board located behind the front panel Power Switch Note that this plug has several alternate positions Each position is labelled for where the end of the plug is to be aligned for each appropriate voltage Move this plug to the new desired position making sure that the plug is fully seated on the mating pins 3 Depending upon which new voltage is chosen it may be necessary to change the AC line fuse Locate the clip mounted Line Fuse adjacent to the Voltage Selector plug Replace the fuse with a new slow blow fuse as follows 9180 100 and 120 VAC 7 amp 220 and 240 VAC 4 amp 9270 100 and 120 VAC 10 amp 220 and 240 VAC 5 amp 4 Replace the cover 5 Obtain a new voltage configuration label from the factory and affix over the original markings on the rear panel Alternately prepare a small self adhesive label and indicate the new voltage with permanent ink Relabelling the unit is a vital safety requirement particularly if the amplifier is sold to a new owner The 9180 9270 Amplifier employs a single control per channel to set the bias operating point of the output stage This bias point is factory set and no
10. CIRCUIT HIGHLIGHTS The input stage of the 9180 9270 Amplifier utilizes four low noise High g JFET s high transconductance junction field effect transistors in a fully complimentary symmetric configuration This circuit configu ration results in excellent front end headroom and a simple straightforward connection to the remainder of the circuitry The ultra low noise characteristics of the JFET s virtually eliminates noise mixing intermodulation with the music signal reducing discordant product frequencies known as noise grain or noise fuzz The input stage is cascode connected to convert the low voltage input system to the high voltage output system and speeds up the front end for superior bandwidth The cascode stage is connected to an emitter follower and current mirror configuration that amplifies the current level about ten times necessary to drive the biasing string and final output stage driver emitter followers The final output stage uses multiple lateral MOSFET s Metal Oxide Semiconductor Field Effect Transistors four devices per channel in the 9180 and six per channel in the 9270 These devices unlike conventional bipolar transistors have a negativetemperature coefficient which means that they do not exhibit thermal runaway Thermal runaway is a phenomenon whereby a transistor heats up as it conducts more current which causes it to get hotter and conduct more current and so on until
11. OHMS 2 ALL CAPACITORS IN MICROFARADS 4 R 3 COUPONENT DESIGNATORS 1 99 LEFT CHANNEL 101 199 RIGHT CHANNEL lt 201 299 COMMON PARTS 101 301 399 CHASSIS POWER SUPPLY RIGHT INPUT 2 5401 2 4 011017 6 020 0320 NOT PRESENT ON V SERIES 9180 CRI 5 CHANNEL ONLY SHOWN FDH400 6 STEREO MONO SWITCH SHOWN IN STEREO 7 VOLTAGE SELECTOR SHOWN IN 100V POSITION 6 OVOIOI amp 02 0102 USE TWO 25 163 SINGLE JFETS OR ONE 2SK389 DUAL JFET 5 R w 9 Q3 Q103 amp 940104 USE TWO 25 74 SINGLE JFETS OR ONE 251109 DUAL JFET 10 R44 R144 R45 R145 R46 R146 R47 R147 21 121 C22 C122 ARE PRESENT ONLY WHEN USING DUAL JFET S 25K389 6 2510 FOR SUBSTRATE BIASING 11 C17 C117 C18C118 C19 C119 NOT USED T220 CR2 FUSE CHART 400 F1 F2 F101 F102 V Q10 a 401 2N5550 6 0 001 R35 RQ R14 R16 47 5K 1 267 Moen E 9270 220 240 ao EN 9180 9270 CIRCUIT SCHEMATIC DIAGRAM se REVISED 1 1 13 91 coy NE FUSE AC POWER INPUT FUSE CHART 201 je C304 LINE VOLTAGE SELECTOR HV SERVICE POLICY AND LIMITED WARRANTY If you encounter any difficulty or have any question concerning your 9180 9270 Amplifier please call our Customer Service Department weekdays 8 a m to 3 30 p m Mountain Standard Time at 602 967 3565 Should you have any doubts as to whether the amplifier is malfunctioning and requires servi
12. c C12 0112 100 Electrolytic C13 c113 0 1 Polycarbonate 0 1 Polypropylene 14 6114 01 Polycarbonate 01 Polypropylene C15 C115 330p Polypropylene 330p Polystyrene C16 C116 0 1 Polycarbonate 0 1 Polypropylene 17 117 Not Used C18 C118 Not Used 19 119 Not Used C20 C120 0 47 Polycarbonate PART NUMBER RMP 4 4752 RMP 4 3322 RMP 4 4752 RMP 4 1000 RMP 4 1000 RMP 4 1000 RMP 4 1001 RMP 4 1502 RW5 100 RMP 4 1001 RMP 4 4754 RMP 4 1004 MP 4 1004 MP 4 1004 MP 4 1004 C 2 752 C 2 752 MP 4 1003 MP 4 1002 MP 4 1822 MP 4 3323 MP 4 1822 MP 4 3323 RMP 4 1001 RMP 4 6811 RMP 4 3322 RMP 4 3322 RMP 4 4752 503 RV 102 PART NUMBER CPP 331 9180 CPS 331 9270 CM 100 9180 CPS 080 9270 CPC 104 9180 CPP 104MC 9270 CERNP 227 CPP 102 9180 CPS 102 9270 CPP 102 9180 CPS 102 9270 BE CPP 221 9180 CPS 221 9270 CPC 104 9180 104 9270 104 9180 104 9270 104 9180 104 9270 1070 1070 104 9180 104 9270 104 9180 104 9270 331 9180 CPS 331 9270 CPC 104 9180 CPP 104MC 9270 CW 474 213 DESIGNATOR C21 0121 22 122 201 C301 C302 C303 C304 Q101 Q2 Q102 Q3 Q103 Q4 Q104 Q5 Q105 06 0106 07 0107 08 0108 09 0109 Q10 Q110 011 0111 012 0112 013 0113 014 0114 015 0115 016 0116 017 0117 01
13. ce please call us before sending in for repair All units being returned regardless of warranty status must receive a Return Authorization RA number In addition we can offer troubleshooting assistance that may simplify or even eliminate the need for factory service The Hafler 9180 9270 Amplifier is warranted to the original owner non transferrable for seven years from the date of purchase including parts labor and return shipping costs within the Continental United States Alaska and Hawaii This warranty applies only to products sold in the United States Of America For warranties outside the U S A please contact your local agent is the owner s responsibility to pay shipping preferably United Parcel Service UPS to the factory collect shipments will not be accepted Units under warranty should be accompanied by acopyof the dated Bill Of Sale Use the original carton and all packing material with the RA number clearly marked on the outside of the package Be sure to include a return address the RA number a daytime telephone number and a brief description of the difficulty including whether it occurs continuously or intermittently This warranty gives you specific legal rights You may also have other rights which vary from state to state 19
14. e performed with the amplifier off The left and right audio inputs to the amplifier are via standard RCA jacks In addition to the printed labelling above the jacks the channels are identified by RED for right channel and WHITE for left channel Connect these jacks to the output of the preamplifier or other signal source When operating the amplifier in the Mono Mode only the left channel input should be used 5 POWER SWITCH LEFT MONO ON GAIN DOWN OFF RACKMOUNT HOLES RIGHT RACK HANDLES 19 VERSION ONLY GAIN 19 VERSION ONLY 9180 9270 AMPLIFIER FRONT PANEL VIEW MONO STEREO SWITCH IN MONO RIGHT OUT STEREO INPUT AC LINE VOLTAGE RATING LEFT MONO INPUT LINECORD CONNECTOR RIGHT LEFT OUTPUT OUTPUT 9180 9270 AMPLIFIER REAR PANEL VIEW OUTPUTS GAIN CONTROLS MONO STEREO SWITCHING SOFT TURN ON OFF SYSTEM THERMAL PROTECTION SYSTEM All output connections to the amplifier must be performed with the amplifier off The left and right audio outputs from the amplifier are via standard 5 way type 3 4 spacing binding posts Connect these binding posts to the loudspeakers The amplifier s binding posts will accept single or dual banana plugs spade lugs pin plugs or bare wires If using bare wires it is recommended that the ends of the wire be tinned with solder so that no stray strands can cause a short circuit to the chassis or adjacent terminals To ensure pro
15. emporarily remove power and reverse the meter leads 5 Again referring to the diagram locate the trimmer potentiometer labelled for the left channel or P101 for the right channel Using a small screwdriver adjust the trimmer for a measured current according to the following 9180 200 mA 9270 300 mA 6 Remove power from the amplifier Wait about one minute for the power supply to discharge and remove the meter connections Replace the fuse 7 Repeat steps 2 3 4 5 and 6 for the other channel 8 Replace the covers The 9180 9270 Amplifier contains five internal fuses one for AC line power and four for DC power supplies These fuses should not generally blow unless malfunction has occurred These fuses should be replaced only by a qualified technician and only with the exact type s and rating of fuse s originally supplied If a fuse is replaced and blows again within a short time check all output connections for short circuits or abnormally low speaker load impedances If all connections and load conditions appear to be correct disconnect all power immediately and return for service If all controls fuses cables etc seem to be functioning properly a process of one at a time component substitution should be employed until the defective unit is identified If only one channel is not functioning properly a one at a time reversal of interconnect and speaker cables from left to right should reveal the malfunctioni
16. er chassis from the rack rails This may accomplished by sandwiching a thin sheet of insulating material i e plastic washers or several layers of electrical tape etc between the rack and the preamplifier and securing the unit with non metallic i e nylon etc hardware It may be necessary to insulate other components so that only one component is directly connected to the rack rails CLEANING If the faceplate should become soiled it may be cleaned with a slightly damp soft cloth and if MAINTENANCE necessary a mild detergent Do not use any abrasive cleaners or solvents Unplug the power cord before attempting any cleaning operations Except as specifically detailed in the owners manual there are no user serviceable parts or adjustments inside the 9180 9270 Amplifier and all servicing should be referred to qualified authorized personnel Parts List DESIGNATORS 1 99 LEFT CHANNEL DESIGNATOR VALUE PART NUMBER 101 1 99 RIGHT CHANNEL 201 299 COMMON PARTS R13 R113 267 RMP 4 2670 301 399 CHASSIS POWER SUPPLY R14 R114 267 RMP 4 2670 R15 R115 1K RMP 4 1001 DESIGNATOR VALUE PART NUMBER R16 R116 1K RMP 4 1001 R17 R117 100 RMP 4 1000 ALL RESISTORS 114 WATT 1 METAL FILM R18 R118 100 RMP 4 1000 unless specified otherwise R19 R119 47 5K 4 4752 R20 R120 562 RMP 4 5620 R1 R101 243K RMP 4 2431 R21 R121 475 RMP 4 4750 R2 R102 243K RMP 4 2431 R22 R122 10 RMP 4 0100 R3 R103 47 5 RMP 4 0475 R23 R123 47 5 RMP 4 0475 R4 R104 47 5
17. guipment and cart combination to topple TABLE OF CONTENTS PERFORMANCE SPECIFICATIONS General Information INSTALLATION Rackmount esisiini Ventilation Rlaesment saeni E e Line Voltage OPERATION CONNECTIONS Power Cord Connection Power Switch Front Panel View Diagram Rear Panel View Diagram OUTPUTS ana Gain Controls Mono Stereo System 9 9 99 Thermal Protection System aueh CIRCUIT HIGHLIGHTS Jul UU ADDITIONAL INFORMATION Loudspeaker Load Impedance Considerations 220 2 0 000 Changing Line Voltage Rating Adjusting Bias General Troubleshooting Hints Ground LOOPS Cleaning Maintenance Parts Liston Functional Block Component Layout Diagram Circuit Schematic Diagram SERVICE POLICY AND LIMITED WARRANTY 3 O PERFORMANCE SPECIFICATIONS GENERAL INFORMATION specifications for 20 Hz 20 kHz at full power into 8 ohms unless
18. n the two channels of the amplifier these controls should normally be set at the same rotational position In the Mono Mode the Left Gain Control effects the overall gain of the amplifier The Right Gain Control has no effect The 9180 9270 Amplifier may be operated in the normal two channel Stereo Mode or may be converted bridged to a higher power single channel amplifier in the Mono Mode Operation of the Stereo Mono switch must be performed with the amplifier off Set the Stereo Mono Switch in the OUT position for Stereo Mode or in the IN position for Mono Mode Mono Mode operation requires different input and output connections consult the sections of the manual titled Inputs and Outputs The 9180 9270 Amplifier is equipped with a Soft Turn On Off System that gradually activates the amplifiers circuitry to avoid spurious noises as the power supply stabilizes At turn off this same system rapidly deactivates the amplifier s circuitry before the power supply begins to collapse again eliminating any spurious noises The 9180 9270 Amplifier is equipped with a Thermal Protection System that constantly monitors the temperature of the heatsinks When the heatsink temperature reaches a pre determined level the amplifier s circuitry is electronically shut down through the same system that provides the Soft Turn On function When the heatsinks cool to a safe operating temperature normal operation of the amplifier resumes
19. ng component Ground loops are characterized by a low level hum or buzz in the system Loops are caused by a voltage potential difference between two points in a ground circuit and aggravated when multiple paths for a given circuit exist Noise free audio performance is dependent upon all grounds being at the same potential with a single path for each ground connection Ground loops can exist in two forms 1 loops created in audio interconnects and 2 loops created between earth grounded chassis Mounting components to a rack with metallic rails may introduce ground loops between associated equipment because the rails can introduce a second ground path The extent of this problem will depend on the grounding arrangements of associated equipment Ground loops can occur in non rackmounted equipment though it is less common If ground loops occur and any other component in the system has a three wire grounded power cord the first step should be to use a ground adaptor with the ground tab or wire of the adaptor not connected on the power cord plug of the preamplifier DO NOT cut off the grounding pin on the plug 11 It may be necessary to use additional adaptors on other grounded components if more than two components are earth grounded In other words only one earth ground per system should exist Another potential source of multiple earth grounds is from coaxial antenna or cable service feeds for FM or video sources which usually are
20. nits wired for 100 220 and 240 VAC are supplied without power cords Local agents will supply cords with male connectors appropriate to the local standard Units wired for 120 VAC are supplied with a detachable AC power cord The female connector plugs into the receptacle provided on the rear panel This power cord is a standard IEC Type 320 3 wire 16 gauge assembly Should replacement ever be necessary be sure to replace it with an identical cord Never remove the grounding pin from the male end of the cord In applications where a grounded outlet is not available a ground adaptor should be employed with the ground tab or wire of the adaptor connected to a suitable earth ground The AC power cord of the amplifier must be connected to a receptacle capable of delivering a minimum of 1200 watts The convenience outlets of some preamplifiers are not rated for this power level Before connecting the amplifier be sure to check the rating of such outlets and take into account the power consumption of any other connected components to determine the total maximum power consumption If the amplifier is connected to a component with a switched convenience outlet then the amplifier s Power Switch may be left ON at all times and the power controlled by the switched outlet If the amplifier is connected to an unswitched outlet then the amplifiers power should be controlled by the front panel Power Switch All input connections to the amplifier must b
21. oft Turn On Off System cooperates with the Thermal Protection System by sensing the high voltage power supply At power up when both the comparator and power supply have stabilized to normal operating levels the Soft Turn On System activates the amplifier circuitry through the same MOSFET switch in the input stage At power down the system deactivates the amplifier rapidly before the power supply begins to collapse This system eliminates spurious noises during the turn on off cycle The power supply utilizes a very large Ul type transformer with dual multi tapped primaries to allow alternate connections for world wide voltage operation Selection of the various voltage options is made via a simple multi position plug inside the unit The UI type of transformer construction results in very low stray magnetic leakage The transformer feeds a conventional split full wave bridge rectifier system Power supply capacitance is 15 000 uF perrail Further power supply de coupling is provided for the input stage of each channel ADDITIONAL LOUDSPEAKER LOAD IMPEDANCE CONSIDERATIONS CHANGING LINE VOLTAGE RATING ADJUSTING BIAS INFORMATION The 9180 9270 Amplifier is suitable for use with a wide variety of loudspeaker types and load impedances Though not rated for impedances below 4 ohms the amplifier is capable of driving lower impedances Operation at low impedances is limited by the thermal dissipation capacity of the heatsinks and the airflow
22. per speaker phasing and freguency response be sure to connect each respective amplifier RED terminal to the speaker RED terminal and the amplifier BLACK terminal to the speaker BLACK terminal The polarity symbols for Stereo Mode are labelled below the amplifier s binding posts For operation in the Mono Mode a single loudspeaker should be connected to the two RED binding posts only No connection is made to the amplifiers BLACK binding posts Connect the speaker s RED terminal to the amplifiers RED terminal labelled and the speaker s BLACK terminal to the amplifiers RED terminal labelled The polarity symbols for the Mono Mode are labelled above the amplifiers binding posts The 9180 9270 Amplifier is equipped with front panel mounted Gain Controls These controls may be used to attenuate the input signal to the amplifier The maximum clockwise position of these controls applies the full input signal to the amplifier Intermediate positions of these controls will partially attenuate the signal and the full counter clockwise position attenuates the input signal completely Most applications will dictate that these controls be set to their maximum clockwise position In situations of unusually high level signal sources or for matching levels in multiple amplifier installations it may be desirable to use an intermediate position of the Gain Controls Unless intentionally introducing different gain levels i
23. rmally should not require adjustment for the life of the product However should improper bias be suspected or if repairs have been made that would require a readjustment of bias the following procedure should be used Review the instructions before attempting this procedure If any doubts exist about one s ability to set the bias it is advisable that the procedure be conducted by a qualified technician 10 GENERAL TROUBLESHOOTING HINTS GROUND LOOPS WARNING UNPLUG THE UNIT FROM AC POWER BEFORE ATTEMPTING THIS PROCEDURE FAILURE TO DO SO CAN RESULT IN SEVERE ELECTRICAL SHOCK REQUIRED TEST EQUIPMENT Milliammeter capable of measuring at least 300 mA 1 Remove the top cover by removing the seven allen head screws three on each side one at rear center 2 Using the diagram Component Layout as a guide find the fuses labelled Fi and F2 for the left channel or 01 and F102 for the right channel 3 Working on one channel at a time remove either one and only of the fuses Connect the milliammeter to the two fuse clips and set the meter to a scale capable of measuring at least 300 mA WARNING THE NEXT STEP OF THIS PROCEDURE CAN EXPOSE THE OPERATOR TO UNINSULATED HIGH VOLTAGES KEEP ALL BODY PARTS CLEAR OF THE INTERNAL CIRCUITRY OF THE AMPLIFIER 4 Apply power to the amplifier and allow the unit to thermally stabilize for about three minutes If using an analog meter and the meter reads backwards t
24. t on a carpeted shelf or in a sealed enclosure Allow for proper clearance above the equipment WATER AND MOISTURE The equipment should not be used in or around water such as a bathtub sink or swimming area Also the equipment should not be used in areas prone to flooding such as a basement POWER SOURCES The equipment should be connected only to a power source of the same voltage and frequency as that listed on the rear panel above the power cord entry point POWER CORD PROTECTION Power cords should be arranged so that they do not interfere with the movement of objects in the room people fan blades utility carts etc Also care should be taken that the cord is not pinched or cut and placed so that it is not in danger of being pinched or cut as in under a rug around a tight corner etc POWER CORD GROUNDING The power supply cord is of a three wire grounded type designed to reduce the risk of electric shock sustained from a live cabinet It is assumed to be of suitable length for most uses of the equipment The use of extension cords and power strips is discouraged unless they are of suitable rating to deliver the required total current for safe operation of all connected equipment Furthermore extension cords or power strips must provide the same three wire grounded connection It is important that the blades of the eguipment s plug be able to fully insert into the mating receptacle Never remove the round grounding pin on the plug in
25. the device self destructs Since MOSFET s are inherently self protecting no sonically degrading complex circuitry is required to monitor and protect the output devices Furthermore these lateral MOSFET s exhibit a very linear input to output transfer function Their connection in circuits and operating characteristics are very similar to vacuum tubes which is perhaps responsible for their widely recognized sonic trait of being very musical and non fatiguing Conversion to Mono Mode is accomplished by driving the negative input feedback point of the right channel with the output of the left channel This causes the right channel to mirror exactly the output of the left channel but 180 degrees out of phase This creates twice the voltage swing to be available across the two red output binding posts This simple method of bridging the amplifier involving only one resistor eliminates the costly and sonically degrading invertor circuitry used in other amplifiers The Thermal Protection System consists of thermistors temperature sensitive resistors mounted to the heatsinks connected to a comparator system that activates when the heatsinks reach an unsafe operating temperature The output of the comparator system is connected to a small switch that turns off the input stage of the amplifier which effectively shuts down the entire amplifier When the heatsinks cool to a safe temperature the amplifier is turned on again The S
26. tside with no dis assembly of the chassis necessary The 9180 9270 Amplifier can produce considerable heat during normal operation The amplifier should be placed on a hard smooth surface to allow air to circulate beneath the unit Additionally allow at least one inch of free space on either side and several inches above and behind the amplifier to allow air circulation around the heatsinks This is particularly important when the unit is installed in a closed cabinet In applications where the amplifier is driving low impedance and or low efficiency loudspeakers at high levels thermal shutdown may occur if inadequate ventilation is provided If this occurs it may be necessary to move the amplifier to a location with better free air circulation The amplifier should be located at least several inches away from sensitive components such as preamplifiers tuners CD players turntables etc due to the possibility of audible hum or buzz from magnetic radiation The 9180 9270 Amplifier is configurable for either 100 120 220 or 240 volt operation This is accomplished by moving the Voltage Selector on the printed circuit board The procedure is detailed in the section CHANGING LINE VOLTAGE RATING Make sure that the unit is configured for your local AC line voltage before attempted use The configuration is labelled directly above the power cord connector OPERATION CONNECTIONS POWER CORD CONNECTION POWER SMICH INPUTS U
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