Hafler-915-pre-sm维修电路原理图.pdf

《Hafler-915-pre-sm维修电路原理图.pdf》由会员分享，可在线阅读，更多相关《Hafler-915-pre-sm维修电路原理图.pdf（27页珍藏版）》请在收音机爱好者资料库上搜索。

1、HafleeH O M EA U D I O C O M P O N E N T SSeries 0915P R E A M P L I F I E RRadioFans.CN 收音机爱 好者资料库Series 915 PreampNOTICE - IMPORTANT SAFETY INFORMATIONRISK OF ELECTRIC SHOCK00 NOT OPENWARNING: TO PREVENT FIRE ORSHOCK HAZARD, DO NOT EXPOSE THISEQUIPMENT TO RAIN OR MOISTURE.AAI0The lightning flash w

2、ith arrowhead symbol withinan equilateral triangle is intended to alert theuser to the presence of uninsulated “dangerousvoltage” within the products enclosure, that maybe of sufficient magnitude to constitute a risk ofelectric shock to persons.The exclamation point within an equilateraltriangle is

3、intended to alert the user of thepresence of important operating and mainte-nance (servicing) instructions in the literatureaccompanying the appliance.1.2.3.4.5.6.7.8.9.READ INSTRUCTIONSAll the safety and operating instructions of your Hafler equipment should be read before power is applied to theeq

4、uipment.RETAIN OWNERS MANUALThese safety and operating instructions should be retained for future reference.HEED WARNINGSAll warnings on the equipment and in the operating instructions are important and should be followed.FOLLOW INSTRUCTIONSAll operating and use instructions are important and should

5、 be followed.HEATThe equipment should be kept away from areas of high temperature, such as heater vents, radiators, stoves/ovens,fireplaces, etc.VENTILATIONThe equipment should be used in an area suitable for proper ventilation. Care should be taken not to impede airflowin and around the cabinet. Do

6、 not mount on a carpeted shelf or in a sealed enclosure. Allow for proper clearance abovethe equipment.WATER AND MOISTUREThe equipment should not be used in or around water, such as a bathtub, sink, or swimming area. Also, the equipmentshould not be used in areas prone to flooding, such as a basemen

7、t.POWER SOURCESThe equipment should be connected only to a power source of the same voltage and frequency as that listed on therear panel above the power cord entry point.POWER CORD PROTECTIONPower cords should be arranged so that they do not interfere with the movement of objects in the room: peopl

8、e, fanblades, utility carts, etc. Also, care should be taken that the cord is not pinched or cut, and placed so that it is not indanger of being pinched or cut, as in under a rug, around a tight corner, etc.10. POWER CORD GROUNDINGThe power supply cord is of a three wire grounded type, designed to r

9、educe the risk of electric shock sustained froma live cabinet. It is assumed to be of suitable length for most uses of the equipment. The use of extension cords andpower strips is discouraged unless they are of suitable rating to deliver the required total current for safe operation ofall connected

10、equipment. Furthermore, extension cords or power strips must provide the same three wire groundedconnection.It is important that the blades of the equipments plug be able to fully insert into the mating receptacle.Never remove the round grounding pin on the plug in an attempt to mate to a two wire u

11、ngrounded receptacle: usea grounding adaptor with the grounding tab or wire suitably connected to earth ground.-l-RadioFans.CN 收音机爱 好者资料库11. NON-USE PERIODSDuring periods of extended non-use, the power cord should be unplugged from the power source.12. CLEANINGThe equipment should be cleaned only as

12、 detailed in the operating instructions.13. OBJECT AND LIQUID ENTRYCare should be taken so that objects and/or liquids, such as cleaning fluids or beverages, are not spilled into theenclosure of the equipment.14. DAMAGE REQUIRING SERVICEHafler equipment should be serviced by qualified service person

13、nel when:A.The power supply cord or plug has been damaged, orB.Objects have fallen, or liquid has been spilled into the equipment, orC.The equipment has been exposed to rain, orD.The equipment does not appear to operate normally or exhibits a marked change in performance, orE.The equipment has been

14、dropped, or the enclosure has been damaged.15. SERVICINGThe user should not attempt to service the equipment beyond that which is described in the operating instructions. Allother service should be referred to qualified service personnel.16. CARTS AND STANDSThe equipment should be used with carts or

15、 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, anduneven surfaces may cause the equipment and cart combination to topple.-2-TABLE OF CONTENTSPERFORMANCE SPECIFICATIONS.4Gener

16、al Information .5INSTALLATIONRackmounting .5Ventilation/Placement.5Line Voltage .5OPERATION/CONNECTIONSPower Cord Connection .5Initial Power-Up/Muting System .5Convenience Outlets .6Line Level Inputs .6Phono Section .6Front Panel View Diagram .7Rear Panel View Diagram .8Tape Input/Record Output .9To

17、ne Controls/Tone Switch .9Volume Control .9Balance Control .9Out 1, Out 2, And Output Switch . 10Headphone Output .10CIRCUIT DESCRIPTIONPhono Section.10Line LevelInpu?Selector System.10J-FET Buffer And Record Output Driver. . 11Tape Monitor Switching.11Volume And Balance Controls.11Line Amplifier. .

18、 11Tone Control System.11Muting System .11 Power Supply.11Headphone Amplifier . 12ADDITIONAL INFORMATIONInstalling Phono Option .12Phono Board Installation Diagram .13Installing Cartridge Loads .14Changing Line Voltage Rating .14Cartridge Loads Installation Diagram .15General Troubleshooting Hints .

19、16Ground Loops .17Cleaning/Maintenance .17Functional Block Diagram .18Main Board Parts List .19Main Board Component Layout Diagram .20Main Board Circuit Schematic Diagram .21Phono Board Parts List .22Phono Board Component Layout Diagram .23Phono Board Circuit Schematic Diagram .24SERVICE POLICY AND

20、LIMITED WARRANTY.25-3-PERFORMANCE SPECIFICATIONSPHONO SECTION(Measured AtREC OUT)LINE AMPLIFIER(Measured atOUT 1 or OUT 2)HEADPHONEAMPLIFIERAll specifications are for 20 Hz - 20 kHz unless specified otherwise.FREQUENCY RESPONSE: +/-0.1 dBMAXIMUM OUTPUT: 5 volts RMSTOTAL HARMONIC DISTORTION AND NOISE

21、:Moving Magnet: .002%Moving Coil: .009%SENSITIVITY (For 0.5 volts RMS at REC OUT, 1 kHz):Moving Magnet: 6.0 mV RMSMoving Coil: 600 uV RMSSIGNAL TO NOISE RATIO (A-weighted, relative to 0.5 V RMS at REC OUT):Moving Magnet: -87 dBMoving Coil: -80 dBMAXIMUM INPUT SIGNAL ( 1 kHz):Moving Magnet: 65 mV RMS

22、Moving Coil: 6.5 mV RMSINPUT IMPEDANCE:Nominal: 47,000 ohmsMoving Magnet: 220 pF as supplied, user adjustableMoving Coil: 100 ohms as supplied, user adjustableGAIN ( 1 kHz):Moving Magnet: +38.5 dBMoving Coil: +58.5 dBFREQUENCY RESPONSE: +/- 0.1 dB (into 33,000 ohms)BANDWIDTH: 8 Hz - 170 kHz, -3 dB,

23、into 10k ohm loadMAXIMUM OUTPUT: 6 volts RMSTOTAL HARMONIC DISTORTION AND NOISE: .008% 2 volts RMSSENSITIVITY (For 0.5 volts RMS Output): 45 mV RMSSIGNAL TO NOISE RATIO (A-Weighted, relative to 2 volts RMS output): -100 dBINPUT IMPEDANCE: 20k ohms (including PHONO/AUX1 when phono option not installe

24、d)OUTPUT IMPEDANCE: 316 ohmsTONE CONTROLSBass: +/- 16 dB 20 Hz, moving inflection, variable turnoverTreble: +/- 14 dB 20 kHz, shelving 5 kHz, fixed turnoverMAXIMUM OUTPUT: 4 volts RMS into 150 ohm loadOUTPUT IMPEDANCE: 150 ohms-4-GENERALjINPUTS: Tuner, Video, CD, Phono/Aux 1, Aux 2, Tape MonitorINFO

25、RMATIONINSTALLATIONOUTPUTS: Out 1, Out 2, Record Out, HeadphoneCONTROLS: input Selector, Volume, Tape Monitor , Tone Control In, Balance, Bass, Treble,Output Off, Power, Phono MM/MCINDICATORS: Mute/Standby, PowerCONVENIENCE OUTLETS: 1 Unswitched, 4 Switched (Polarized)(Convenience Outlets are not in

26、cluded on 200-240 VAC units)PHYSICAL DIMENSIONS:17” (W) x 7-5/8” (D) x l-3/4” (H) (excluding feet); Faceplate 17” or 19” (W).43.2cm (W) x 19.4cm (D) x 4.5cm (H) (excluding feet); Faceplate 43.2cm or 483cm (W).POWER CONSUMPTION (Excluding Convenience Outlets): 9 watts Max.AC LINE VOLTAGE OPERATING RA

27、NGE: (exceeding lower limit will activate muting circuit;exceeding upper limit will result in overheating and/or component damage)100 - 120 Volt 50/80 Hz Models: 85 - 130 volts200 - 240 Volt 50/80 Hz Models: 170 - 280 voltsRACKMOUNTINGVENTllATlON/PLACEMENTLINE VOLTAGEThe 915 Preamplifier is supplied

28、 in either a 17” Black Version, or a 19” Silver Version. The 19model has rackmounting holes provided for installation in equipment racks. The holes are onstandard EIA spacings.The 915 produces very little heat during operation, and therefore requires no special consider-ations for ventilation. The p

29、reamplifier should be located at least several inches away fromcomponents that contain large power transformers (such as power amplifiers), due to thepossibility of audible hum or buzz from magnetic radiation.The 915 Preamplifier is configurable for either 100 - 120 volt, or 200 - 240 volt operation

30、. Thisis accomplished by changing internal jumpers on the printed circuit board. The procedure isdetailed in the section “CHANGING LINE VOLTAGE RATING”. Make sure that the unit isconfigured for your local AC line voltage before attempted use. The configuration is labelleddirectly above the power cor

31、d connector.OPERATION/CONNECTIONSPOWER CORDCONNECTIONINITIAL POWER-UP/MUTINGSYSTEMUnits wired for200-240 VACare supplied without power cords. Local agents will supply cords withmale connectors appropriate to the local standard.Units wired for 100-120 VAC are supplied with a detachable AC power cord.

32、 The femaleconnector plugs into the receptacle provided on the rear panel. This power cord is a standardIEC Type 320, 3-wire, 18 gauge assembly. Should replacement ever be necessary, be sure toreplace it with an identical cord.Never remove the grounding pin from the male end of the cord. In applicat

33、ions where a groundedwall outlet is not available, a ground adaptor should be employed, with the ground tab or wire ofthe adaptor connected to a suitable earth ground.For units wired for 200-240 VAC, the front panel Power Switch controls the power to thePreamplifiers circuitry. If desired, this swit

34、ch may be left “on” at all times to allow circuits to bethermally stabilized for maximum fidelity as soon as the system is used.-5-IEC Type 320, 3-wire, 18 gaugeCONVENIENCE Units wired for 200-240 VAC are supplied without convenience outlets to conform to RegulatoryOUTLETSSafety requirements.LINE LE

35、VELINPUTSPHONO SECTIONThe ground terminal near the MC/MM switch is provided for turntable frame grounding via the extra(When Installed)ground wire provided on most turntables.For units wired for 100-120 VAC, the Power Switch controls the Switched Convenience Outlets only.As soon as the 915 is plugge

36、d into the AC line, power is applied to the circuitry (regardless of theposition of the front panel Power Switch). Therefore, all connections should be performed with the unitunplugged.For all units, when power is applied, the Ready Light will glow red for several seconds, indicating thatthe Audio a

37、nd Headphone Outputs are muted. Once the delay period has passed and the powersupply has stabilized, the light will turn green. The preamplifier is now ready to enjoy.The muting will reactivate immediately (and the Ready Light turn red) upon loss of AC line voltage,(or operating the Power Switch on

38、200-240 VAC units), or if line voltage falls below a level whichprecludes proper operation of the preamplifiers circuitry.Units wired for 700- 720 VAC have a total of five outlets for connection of associated components. TheUnswitched Outlet is powered at all times, which should generally be used fo

39、r a turntable or tape deck.The remaining four Switched Outlets are powered when the front panel Power Switch is engaged, asindicated by the switchs green pilot light.The maximum power available from these outlets is 1200 watts total. This total power may be drawnfrom a single outlet, or a combinatio

40、n of outlets. Since some power amplifiers consume more than1200 watts at maximum output, check the power amplifiers rating before connecting to theseconvenience outlets.The inputs labelled CD, Tuner, Video, Aux 2, and Phono/Aux 1 (when the Phono Option is notinstalled), are identical line level inpu

41、ts. The names chosen for these inputs are for convenience only,and may be used interchangeably, or for any other type of line level source. These inputs are selectedvia the rotary front panel Selector Switch.The Phono/Aux 1 input is converted from a line level input to a high gain RIAA phono input w

42、hen thePhono Option is installed. See Phono Section.The 915 Preamplifier is available with an optional Phono Amplifier section. This option may beinstalled at time of purchase, or at a later date.Inclusion of this option is indicated by the presenceof a switch button protruding from the rear panel o

43、pening marked MC/MM. Otherwise, this openingwill be filled by a plastic cover.The MC/MM switch should be set to MC for low output (typically 0.2 - 0.5 mV) moving coil cartridges,and set to MM for high output (2 - 5 mV) moving coil cartridges or moving magnet cartridges.NEVER OPERATE THE MC/MM SWITCH

44、 UNLESS THE VOLUME CONTROL IS TURNED FULLYDOWN. The very high gain present in the Phono Amplifier can result in switching transients capableof blowing amplifier or speaker fuses, and possibly damaging some loudspeakers.As supplied from the factory, the phono cartridge input termination is 47,000 ohm

45、s in parallel with 220pF in the Moving Magnet mode, and 100 ohms in the Moving Coil mode. The value of capacitanceand resistance is user selectable via plug-in components. See “Installing Cartridge Loads” for furtherinformation and instructions.-6-INPUT SELECTORBALANCE CONTROLTREBLE CONTROLVOLUME CO

46、NTROLBASS CONTROLHEADPHONE JACKPOWER SWITCHUP TO TURN ONSWITCHED OUTLETS*I0-lIwA0CJ 0.RACKMOUNT HOLES(19” VERSION ONLY)TAPE MONITOR SWITCHTONE IN SWITCHOUTPUT OFF SWITCHREADY LIGHTUP TO MONITOR TAPE INPUTUP TO ACTIVATE BASS & TREBLEUP TO TURN OFFRED FOR MUTE ACTIVATEDOUT1 &OUT2GREEN FOR OPERATE915 P

47、REAMPLIFIER FRONT PANEL VIEW*lOO-120 VAC UNITS ONLY.200-240 VAC UNITS ARE WITHOUT CONVENIENCE OUTLETS:POWER SWITCH CONTROLS PREAMPLIFIER POWER.AC LINE VOLTAGERATINGUNSWITCHED OUTLET*O U T 2TAPEV I D E OC DPHONO CHASSISOUT 1REC OUTAUX 2TUNERPHONO/AUX 1GROUNDLINE CORD CONNECTORSWITCHED OUTLETSOUTPUTSI

48、NPUTST O P R O W - RIGHT CHANNELBOTTOM ROW - LEFT CHANNELMC/MM SWITCH(PHONO OPTION ONLY)IN-MOVING COILOUT - MOVING MAGNET915 PREAMPLIFIER REAR PANEL VIEW*100-l 20 VAC UNITS ONLY.200-240 VAC UNITS ARE WITHOUT CONVENIENCE OUTLETS.TAPE INPUT/The 915 incorporates one monitoring loop for use with tape de

49、cks, or other input/output signalRECORD OUTPUTprocessors.TONE CONTROLS/TONE SWITCHVOLUMECONTROLBALANCECONTROLThe Ret Out jack feeds a signal to a tape recorders input. The signal present at this output isthe same as indicated by the Selector Switch. This output may alternately be used to feed theinp

50、ut of a signal processing device, such as an equalizer.Though rare, it is possible that some external devices connected to Rec Out may cause slightdistortion to the main signal path when that device is turned off. This is due to possiblesemiconductor junction rectification in unpowered circuits. If