Hafler-DH110-pre-sm维修电路原理图.pdf

THEPREAMPLIFIERDH-110INSTRUCTIONSfor ASSEMBLYand OPERATIONLM132$3.00Please refer to this serialnumber in all communicationsregarding this equipment.THE DAVID HAFLER COMPANY5910 Crescent Boulevard, Pennsauken, New Jersey 08109RadioFans.CN 收音机爱 好者资料库DH-110SPECIFICATIONSThe numbers in parentheses refer to the paragraph in the IHF specifications manual which defines the test procedure.2PHONO PREAMP SECTIONRated Output: 3 Wms, 8 Hz-105 kHzMaximum Output (3.5): 12 Vrms, 20 Hz-20 kHz at recording outputTotal Harmonic Distortion: Less than 0.0006% 1 kHz, 3 VrmsFrequency Response (3.13): +0, -0.25 dB, 20 Hz-20 kHzRIAA Equalization Accuracy: +0, -0.1 dB, 30 Hz-15 kHzFull Power Bandwidth: -6 dB, 4 Hz-210 kHzSensitivity (3.7): 12.5 millivoltsMaximum Input Signal 1 kHz (3.8): 300 millivolts; 3 V 20 kHzGain: 34 dB 1 kHzInput Impedance: 47,000 ohms in parallel with 30 pF; user adjustable.Plug-in capacitors are installed to increase thisto 150 pF on Phono 1; 250 pF on Phono 2Signal to Noise, weighted (3.12): 87 dBSlew Rate: 12 volts per microsecondLINE AMPLIFIER SECTIONRated Output: 3 Vrms, 4 Hz-210 kHzMaximum Output (3.5): 14 Vrms, 20 Hz-20 kHzTotal Harmonic Distortion (3.4): Less than 0.001%, 20 Hz-20 kHzFrequency Response (3.13): +0, -0.1 dB, 20 Hz-20 kHzFull Power Bandwidth: -6 dB, 2 Hz-420 kHzSensitivity (3.7): 50 millivoltsMaximum Input Signal 1 kHz (3.8): 14 Vrms; volume control -20 dBGain: 20 dB 1 d BInput Impedance: Greater than 25,000 ohmsSignal to Noise, weighted (3.12): 90 dBSlew Rate: 12 volts per microsecondRise Time: 2.5 microseconds maximum, Phono in / Line out, 10 Vp-p,1 kHz square wave; load is 10,000 ohms in parallel with 10 nFCrosstalk (3.14): down 72 dB, any input to any outputSeparation (4.2): greater than 82 dB 1 kHz; greater than 52 dB 20 kHzGain Tracking Error (4.4): less than 0.5 dBMaximum Output Noise: less than 350 microvolts, widebandless than 95 microvolts, A weightedwith 1 Kohm input termination, volume full CWBass Control: 217 dB 20 Hz, moving inflection, variable turnoverTreble Control: 17 dB 20 kHz, shelving 5 kHz, fixed turnoverFilter Response: -3 dB 25 Hz; -6 dB 15 Hz; -12 dB 8.2 Hz; -25 dB 3 HzFilter Cutoff (3.13.2.2.1; 3.13.2.2.2): 25 Hz; -12 dB/octaveGENERAL SPECIFICATIONSSemiconductors: 30 transistors, 3 ICs, 12 diodes, 2 LEDsInputs: 2 Phono, Tuner, Compact Disc or Video, 2 Tape recorders, EPLOutputs: 2 Tape (buffered), 2 Line, EPL, Headphone JackControls: Volume, Balance, Bass, Treble, Input Selector, Phono l/2 Selector,Monitor Selector, Mono-Stereo, Filter, External Processor Loop,Tone Control Engage, PowerIntermodulation Distortion: Both SMPTE and CCIF IMD at operatinglevels from phono input to line output are below theresidual of currently available instrumentationAC Supply Voltage: 100-130 and 200-260 VAC, 50/60 HzPower Consumption: 3.5 wattsAC Convenience Outlets: 3 switched, 5 amp continuous, 72 amp surge1 unswitched, 5 amp continuousSize: 17” wide x 3” high x 8” deep19” rack mounting accessories includedShipping Weight: 12.5 lbs.Net Weight: 10 lbs. Copyright 1985. All rights reserved.RadioFans.CN 收音机爱 好者资料库INTRODUCTIONYour preamplifier is the control center of your musicsystem, acting as an interface between the soundsources-record players, tape recorders, FM and Videotuners-and the power amplifier which drives theloudspeakers. As the focal point of your system, it shouldbe attractive and easy to use, versatile and yet functionallyunobtrusive. It should contribute a minimum of noise ordistortion while providing signal amplification, control ofthe signal level, and applicable modification of the fre-quency response.The DH-110 achieves all these objectives with greatversatility, providing for two record players with magneticcartridges, two tape recorders, a tuner, and an additional stereoinput for a compact (digital audio) disc player or video audio. Italso includes inputs and outputs for an external signal processorsuch as a graphic equalizer, time delay device, or noisereduction unit. The performance of the DH-110 is exemplary,and its assembly from an array of discrete components ofexceptional quality should ensure reliability and longevity of itscapabilities.Exceedingly low noise and distortion is a hallmark of theDH-110. Noise is essentially inaudible in the absence of asignal, and distortion of all types, both steady state andtransient, is at or below the threshold of the finest mea-surement capabilities. These excellent characteristics aremaintained far outside the customary 20 Hz to 20 kHzband, and signals well beyond that are handled without theneed to restrict bandwidth.Precise interchannel balance at all frequencies is main-tained with close tolerance components, and RIAA phonoequalization is engineered to very narrow limits, maintain-ing accurate phase relationships and correct spatialperspectives, as well as exceptional unit-to-unit consis-tency. The tone controls, which can provide contouring ofresponse for individual needs when switched in, are nor-mally isolated from the circuit for ruler-flat response.The components in the DH-110 have been selected fortheir superb audio performance as well as for their reliabil-ity. They have been incorporated in the unique Hafler fullycomplementary symmetry push-pull circuit in a carefullydesigned circuit board layout which reduces crosstalk andmaintains separation for a synergistic audio result thatdefies comparison, regardless of cost.Those who have chosen to build the kit will find that itsstep by step instructions will ensure a properly workingunit even for the novice builder. A substantial amount ofpreassembly has enabled us to check out each kit in nearlyevery aspect of performance, and makes the DH-110 a par-ticularly fast, easy and enjoyable construction project,which you will likely complete in one evening.We suggest that you read the installation and operationsections of this manual carefully, even though much maybe familiar to you. There are some subtle and significantpoints which may be new, and their proper appreciationwill enable maximum satisfaction with your DH-110. Wewish you to have the very best in sound.CONTENTSInstallation.Page 4Operation.5Assembly Instructions. .7Building the Kit.9PC-14 Diagrams.12If a Problem Arises.15Overseas AC Line Connections. .15Additional Information.16Functional Block Diagram.16Component Values.19Schematic Diagram.20Kit Parts List.22Service and Warranty.23Pictorial Diagram.Insert3The DH-110 is provided with accessory Rack Mount endcaps in addition to the standard end caps installed on theunit. These accessory caps extend the width of the frontpanel to that of a standard 19” rack, with appropriatemounting holes. Installation instructions are detailed laterin this manual under Additional Information.POWER CONNECTIONSAs assembled, units are normally wired for 120 VAC,50-60 Hz, as in the USA, unless they are specially iden-tified on the carton. In the Additional Information sectionyou will find diagrams of alternate wiring of the powertransformer to conform to other line voltages.The power regulation of the DH-110 will provide full per-formance with line voltages which may vary substantiallyfrom the standard. Units wired for 120 volts, for instance,will work properly with line voltages between 95 and 130volts.Accessory AC outlets are provided on the back panel forother equipment. One unswitched outlet is provided for aturntable or tape recorder whose mechanical system mayrequire disengagement through its own power switch.Most units, including power amplifiers, tuners, and manytape recorders and record players, may be connected tothe switched outlets for convenient remote switching fromthe preamps front panel. The DH-110 power switch hasbeen tested to provide adequate capacity for any Haflerpower amplifier and typical related equipment. You shouldheed the maximum power rating printed on the back panelof the unit.INPUTS-Magnetic PhonoThere are two pairs of phono inputs, identified as Phono1 and Phono 2. These are independent, and thus they mayhave different capacitive termination for differing car-tridge requirements. As assembled, Phono 1 is providedwith a compensation capacitor of 120 picofarads, andPhono 2 is provided with 220 picofarads. One of these val-ues will accommodate most Moving magnet cartridges.These have output levels intended for normal phono in-puts (0.5 millivolts per centimeter or higher) and are themost popular. Some high output moving coil design car-tridges are not sensitive to capacitive loading, so they maybe used with either input.Though some phono cartridges are comparatively freeof loading sensitivity, if the cartridge manufacturerspecifies the proper load capacitance (which is the sum ofthe preamps internal capacitance, and the cables you use,as well as the above described capacitor), the most accu-rate sound will be obtained by following that recommenda-tion. If you have chosen the DH-110 for its sonic attributes,you will be more likely than most to be aware of these dif-ferences, and will want proper cartridge termination.The Additional Information section of this manual de-tails the determination of the loading capacitor for aspecified cartridge load. It also describes how the resistiveload of the phono inputs may be changed, if needed, fromthe standard 47K ohms.Moving coil design cartridges often require an auxiliarystep-up transformer or pre-preamplifier (head amplifier)because of their low output signal. The DH-110 has provi-sion for internal addition of an accessory Hafler pre-preamplifer which you or your dealer can install at anytime. This enables the Phono 1 input to accommodate suchcartridges directly. The Additional Information describesits installation.Adjacent to the Phono 1 input sockets are two Groundterminals on the back panel. These thumbscrews providefor connection of separate ground wires often provided onturntables, or as part of their audio cables. This chassisground may sometimes reduce the hum level of a systemwhen it is connected to an earth ground, such as a coldwater pipe, or the ground wire of 3-wire house wiring.However, the need for such connection varies with indi-vidual situations. After the system is operative, using aphono source, experiment with and without an earthground to determine which provides the lowest hum, anduse that.IMPUTS-Tuner, CD/VideoThese are high level (line-50 millivolts or more) signalsfrom FM, AM or TV tuners, or compact digital audio disc,video disc, or VCR players. These inputs are grounded at theselector switch when they are not chosen for listening. The inputimpedance is approximately 33K ohms.INPUTS-Tape 1, Tape 2These are at line level and impedance. They connect toTape Play outputs on the tape deck. They are not groundedwhen unused, since they can be connected by either themain selector switch or the Tape Monitor switch. They areterminated with 1 megohm resistors to avoid a possibleswitching transient.RECORDING OUTPUTSThese connect to the Line Inputs of tape decks. The twopairs of outputs are wired in parallel. Thus two tape recor-ders receive identical signals. These outputs are bufferedwith a series resistor, and have an output impedance of1.5K ohms. To provide full specification performance, thetotal tape recorder load should not be lower than 10K ohms(i.e. two 20k ohm recorder inputs on each channel).Because it is possible that a preamplifiers overall per-formance may be adversely affected by rectification ef-4fects that can result from unpowered electronic circuits inthe tape decks when they are connected to the RecordingOutputs, it is recommended that tape recorders beswitched on when the preamplifier is in use. This is acommonly overlooked cause of less-than-idealpreamplifier performance.Signals at these outputs are at line input level (phonosignals are first amplified and equalized). These outputsare unaffected by external processing circuits, or by theDH-110s Mono, Filter, Tone or Volume controls. Only sig-nals indicated by the Selector switch are available, includ-ing the other tape input, so tape copying is provided usingeither recorder as a source.LINE OUTPUTSTwo pairs of outputs are provided for your powerwhich is otherwise a possibility. We recommend that youturn off power amplifiers before connecting headphones,or that they be plugged in before the system is switched on,as a precaution.The Direct outputs provide conventional signal levelsindependent of the headphone circuit. If headphones areplugged in, the level of the Direct output will be greatlyreduced. These outputs should not be used when head-phone use is anticipated.The performance specifications will be met so long asthe input impedance of the power amplifier is 10K ohms orhigher, and the cable capacitance is less than 1Onf. This isno problem with typical interconnecting cables up to 10feet. If you are planning to use very long cables betweenpreamp and power amplifier, special low capacitance cablecan be obtained.amplifier connection. The set labelled Via Phones isEXTERNAL PROCESSING LOOPsuggested for those who regularly listen through head-Send is an output at line level for the purpose of drivingphones as an alternative. These are wired so that whenan external signal processor such as an equalizer, timeheadphones are plugged in, the signal is disconnected fromdelay, or noise reduction unit. Like the recording outputs,the power amplifier. Two purposes are thus served. Sincethe load impedance should not be less than 10K ohms. Themany headphones require fairly high volume control set-EPL Return input impedance is 33K ohms, and shouldtings, you avoid inadvertent high signal levels to youralso be at line level. The EPL Return can also function asspeakers. And a power amplifier which is turned off can-an additional high level input, switched from the frontnot degrade the quality of signal to the headphones-panel.OPERATIONWhen you turn on the DH-110, power is also applied tothe switched AC outlets on the back panel. One of the redLEDs on the front panel will light, indicating that thepreamp is functioning. Typically, it will be the left-mostLED, indicating that the Selector switch is determiningthe signal source. At turn-off, it is normal for the LED tofade slowly as the operating voltages decline.DELAYED TURN-ONAn internal muting circuit prevents the voltage tran-sients which may occur at turn-on or turn-off from causingannoying noises, blown fuses or damaged loudspeakers.At turn-on, the Line Outputs (but not the RecordingOutputs or EPL Send output) will be held near ground po-tential for a few seconds until the internal voltages havestabilized, and the unit is ready for operation. Only a faintoutput can be heard during this time.At turn-off, whether by operating the preamps powerswitch, or as a result of external AC failure (a brown-out,pulled plug, or blown house fuse), the line output will beinstantaneously lowered. Following power interruption,the muting circuit will initiate a few seconds delay beforeallowing full signal at the