Hafler-DH220-pwr-sm维修电路原理图.pdf

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1、THEPOWERAMPLIFIERINSTRUCTIONSfor OPERATIONand KIT ASSEMBLYCAUTION:IF THE SPEAKER FUSES BLOW,SOME DISTORTED SOUND CAN BEHEARD. THEREFORE IF AMPLIFIERMALFUNCTIONS, ALWAYS CHECKFOR BLOWN FUSES FIRST.serial number in all communicationsTHE DAVID HAFLER COMPANY5910 Crescent Boulevard, Pennsauken, New Jers

2、ey 08109RadioFans.CN 收音机爱 好者资料库Hafler DH-200 Power AmplifierINTRODUCTIONThe Hafler DH-220 is a two channel audio power amplifierdesigned to the very highest performance standards. It isavailable either as a kit, or fully assembled. Its 115 watt perchannel power rating is sufficient for driving all l

3、oudspeakers inhome applications, and its design assures extremely low distor-tion of all types. A combination of high performance, depend-ability, reliability, and moderate price is in the Hafler tradition ofusing the very latest technology to provide outstanding value.The DH-220 circuit is a refine

4、ment of the DH-200 design, aHafler landmark which has achieved worldwide recognition,and has elicited glowing reviews since its 1979 introduction. Asin the DH-110 preamplifier, particular attention has been paid tocomponent quality, using polypropylene or film capacitorswherever feasible, for exampl

5、e, for superior sound.Combining the latest power MOSFET technology with uni-quely simple and effective circuit topology reduces distortion ofall types, and at all power levels, over the full audio frequencyspectrum, to the vanishing point. In addition to its pace-settingperformance achievements, the

6、 conservative mode of opera-tion accomplishes a new high in long term reliability and excep-tional resistance to abusive operating conditions. This is one ofthe direct benefits of MOSFET utilization in overcoming aserious limitation of conventional transistors - their tendencyto self-destruct under

7、other than normal operating conditions.So rugged is the DH-220 that it can deliver more than tenamperes into a short circuit!The speed - measured as the slew rate - of this designdelivers unmatched transient linearity, revealing the mostdelicate shadings, textures and nuances of the music, surpassin

8、gthe capabilities of the most revealing loudspeakers and cart-ridges by a wide margin. Coupled with its unconditional stabili-ty, and ability to deliver adequate power into any loudspeakerload, the result is absolute freedom from listening fatigue. Thelonger you listen to this phenomenal amplifier,

9、the more certainyou will be that you could not have made a better choice.The oversized power transformer and bridge rectifier; themassive heat sinks; the conservative operating levels of theMOSFET output devices - all are evidence of the design effortsto achieve exceptional reliability simultaneousl

10、y with state ofthe art sonics and specifications. And this circuit is convertible toa high power monophonic amplifier with comparable stabilityand specifications.The fully complementary, symmetrical push-pull circuit,which is direct coupled throughout (except at the input), incor-porates all silicon

11、 devices in a format which is directly related tothe highly acclaimed DH-110 preamplifier. Its unique self-protecting output stage prevents the thermal runaway which isa common threat to solid state amplifiers. The ruggedness andconservative operation of the output stage allows the DH-220 toavoid th

12、e need for special protective circuits which could com-promise audio performance. Basic protective systems providemaximum security against malfunction damage to the amplifieror the speaker: the AC line fuse, B + fuses, thermal breakers,and loudspeaker fuses. Nothing hinders the essential purity ofth

13、e audio signal.Those who use these instructions to assemble the DH-220 kitwill find that the left and right audio modules (printed circuit andheat sink assemblies) are preassembled and pretested. Thisgreatly simplifies the kit assembly so that it can be done in only afew hours without special skills

14、 or know-how. Because of themodular arrangement, it is possible to operate on one channel ifthe other requires service, and avoids the need to return the en-tire amplifier in cases where only one channel is at fault.Accessories for special applications include provision formonophonic use; a panel fo

15、r standard 19” rack mounting; andan alternative power transformer for international AC linevoltages.Through advanced engineering geared to the audio perfec-tionist, and an efficient no-frills approach, Hafler is making hightechnology high fidelity affordable.CONTENTSOperation . . . . . . . . . . . .

16、 . . . . . . . . . . . .Page 3Assembly Instructions.4Wiring the Kit.6If Problems Arise.10Service and Warranty.11AC Line Connections for Overseas Use.12Kit Parts List.13Schematic Diagram.14Component Value Listing.15Pictorial Diagram.InsertCopyright 1984, All rights reserved.RadioFans.CN 收音机爱 好者资料库DH-

17、110INSTALLATIONThe DH-220 is most likely to be installed out of sight in mostapplications, since its power may be controlled by the ACswitching of most audio preamplifiers, like the Hafler DH-110. Ifyour control unit does not provide switching capacity sufficientfor the amplifier s 7 amp needs (plus

18、 other equipment it is alsoswitching), you should use the amplifier s own power switch. Inthat case, turn on the preamplifier first; then turn the amplifieron a few seconds after the preamp has been turned on, to avoidany unnecessary turn-on transients from some preamplifiers.Likewise, switch the po

19、wer amplifier off first.If the amplifier is to be installed close to a record player, youshould first check its position for freedom from hum pickup bythe cartridge from the field radiated by the power transformerof the DH-220. Although the design of the transformerminimizes such radiation, certain

20、cartridges are more sensitivethan others, and require separation from the amplifier. Check ata comparatively high volume setting, and while swinging thetone arm throughout its arc. Often a few inches additional spac-ing will eliminate the problem.Be sure to provide sufficient ventilation for the amp

21、lifier.Unobstructed air circulation around the finned heat sinks andabove the amplifier is important for long, trouble-free life. Neverput anything on top of the cover perforations. It is normal for thetop and the heat sinks to become warm in use.It is expected that the amplifier will always be rest

22、ing on itsfeet, which should be on a hard enough surface that air flowunderneath is not obstructed. If it is mounted in a rack, orthrough a panel, the feet may be removed so long as adequateventilation is provided through the bottom openings.OPERATIONThe red pilot lamp which is integral with the pow

23、er switchglows whenever the amplifier is turned on. A blown AC line fuseis the most likely cause if it is not illuminated when the amplifieris switched on.The pilot lamp also provides a high temperature indication. Inthe unlikely event that the amplifier ceases to function, and theamp blinks on and

24、off steadily, it indicates that one of the ther-mal breakers has shut down the amplifier because of excessivetemperature rise in a heat sink. When the heat has dissipated ina few minutes, the amplifier should return to normal operation.If the lamp again blinks, check for insufficient ventilation, or

25、 anexcessive input signal, or an input which may have dangeroussignal content (such as oscillation). Failing evidence of this, theamplifier may have malfunctioned. Because of the very largeheat sinks, it is highly unlikely that any normal signal will causethe amplifier to overheat.Loudspeaker Fuse S

26、electionThe DH-220 power amplifier is supplied with 2 amp fuses inthe speaker lines. Experience has shown that since an overloadmust exist for a few seconds for a fuse to blow, a 2 amp fuse willprotect most speaker systems, and only blow when overload oc-curs. Smaller fuses tend to blow too easily,

27、and larger fuses donot adequately protect most speaker systems.A pair of 5 amp fuses are also supplied as alternatives for thespeaker fuse holders. These should be substituted if the poweroutput of the amplifier is to be tested, and these or intermediatevalues may be used if the amplifier is to be o

28、perated at very highpower levels into 4 ohm loads.If the manufacturer of your speakers recommends a specificvalue of fuse for their protection, we suggest that you obtainA C fuses of that value and install them in the back panel.Loudspeaker Power RatingsThere are no U.S. standards for rating the pow

29、er handling ofloudspeakers. As a result, the manufacturers usual “musicpower” ratings, or suggested amplifier limits, are of onlyminimal help in determining safe operating levels withamplifiers which can deliver substantial amounts of power. Youmust take into consideration the type of music, and the

30、 levelsyou like, to provide long term trouble-free operation of yourspeaker choice, when you have a sizeable amplifier like theDH-220.ConnectionsACThe AC power cord should be plugged into 120 volts, 60 Hz,on the switched outlet of a preamplifier which can provide atleast 7 amps, or 840 watts. Then t

31、he amplifier power switch maybe left on, and it will be controlled by the rest of the system. Or. itmay be plugged into a 120 volt wall outlet, and switched on andoff independently.If your line (mains) voltage is different, be sure you have thealternate power transformer which can accommodate severa

32、lline voltages, and be sure it is wired for your mains voltage asdescribed later in this manual before you pIug in the amplifier.InputConventional shielded cables, such as those supplied withyour preamplifier, provide the input signal to the sockets on theback panel of the DH-220. Be sure that the o

33、uter shield connec-tion is secure, to avoid hum. The length of these cables (so as topermit remote location of the amplifier, if desired) is limited onlyby the output impedance of the preamplifier. If it is 600 ohms orless, as with the DH-101 and DH-110 Hafler preamps, for in-stance, cable lengths u

34、p to 50 feet are premissible without loss ofDH-101performance. Special low capacitance cables enable evengreater distance between preamp and amplifier. It is desirableto keep the left and right input cables close together throughouttheir length to minimize the likelihood of hum pickup. Also, youshou

35、ld avoid running them parallel to AC cords - these shouldbe crossed at right angles.OutputThe loudspeakers (or headphones) connect to the red andblack terminals on the back panel. These binding posts provideseveral convenient alternative connecting methods. The screwcap may clamp the bared wire end,

36、 or a “spade lug” attached toit, but a better connection will be made by locating the hole drill-ed through the shaft of the terminal when the cap is unscrewed.Insert the twisted end of the bared wire so that the cap willclamp it in place. Always be sure that no strands of wire areunsecured, and tha

37、t the bared end is not too long to risk contac-ting other elements. A soldered end or fitting is the safest solu-tion.These terminals also accept standard plug-in “banana pin con-nectors,” including the double ones with standard 3/4” spacing,available from electronic supply houses. These are the mos

38、tconvenient, especially if you may wish to interchange speakersoccasionally.It is important to maintain correct phasing of the speakerswhen making their connections. Some speaker terminals arecoded red and black, or + and -, etc. It is important that the“sense” of one speaker s connections match the

39、 others. If one isreversed, you will find that the sonic image has a “hole in themiddle,” and that it is deficient in bass. Speaker wire alwaysidentifies one conductor to make this easy. There may be amolded ridge in one lead, or the color of the insulation on onewire is different, or the wire itsel

40、f may be color coded. If pinplugs are used, be sure they are color coded, or that you followthe indexing mark on one side of the double connectors.Select speaker wire of sufficient size to preserve the highdamping factor (and excellent speaker control) of youramplifier. Standard 18 gauge lamp cord (

41、“zipcord”) is satisfac-tory for distances up to 30 feet for an 8 ohm speaker. As thedistance increases, larger wire sizes are recommended. Thenext larger wire size is#16, and it is often preferred by perfec-tionists. If you have 4 ohm speakers, the maximum cable lengthfor best results is halved.The

42、black output terminals are electrically connected to thechassis internally. Be certain that when the amplifier is operatedin its normal stereo mode that the red output terminals are neverconnected together. In the special case when the amplifier hasbeen internally modified for monophonic bridged ope

43、ration,the output is taken from the two red terminals only. Then, theblack terminals are left unconnected.Headphones are normally operated from the loudspeakeroutputs, but are usually connected through a junction boxwhich provides switching from phones to speakers. Such a boxusually provides some ad

44、ded resistance to reduce the sensitivityof the phones, and thus minimize the likelihood of hearing com-ponent noise, because of the low setting required at the volumecontrol. Some headphone boxes utilize a “common ground”system which makes it particularly important that you carefullyobserve the prop

45、er connections. While the black ground ter-minals can be connected together, the red ones must not be.Some headphones, such as electrostatic types, are less sen-sitive and may need little or no resistance in series for normaloperation. These could be easily interchanged with thespeakers through the

46、use of double banana plugs.KIT ASSEMBLY INSTRUCTIONSThere are three basic rules for success in electronic kitbuilding:1. Read the instructions carefully, and follow them in order.2. Make secure solder connections which are bright andsmooth.3. Check your work carefully after each step.The DH-220 ampl

47、ifier is a versatile component withsophisticated circuitry which has been made remarkably easyto build by individuals with many years of experience in thedesign and engineering of the finest performing audio kits, andin the preparation of their manuals.Kit building should be fun, and we are certain

48、you will find thisto be so. Assembly will be faster, easier, and more enjoyable ifyou have someone help you by reading the steps aloud, selec-ting the required parts, and preparing the necessary wirelengths in advance as you proceed. Fatigue increases the risk oferror, so take a break rather than pu

49、sh to early completion.There are relatively few separate components in this design, tomake it easy to pack everything away, if need be.Your work area should have good lighting, the proper tools,and a place where the large pictorial diagram can be positionedwithin easy reach for checking. The tools s

50、hould include:1,2.3.4.5.6.7.8.9.A 40 to 100 watt soldering iron with a 1/4 or smaller tip whichreaches at least 600F.60/40 (60% tin) ROSIN CORE solder, 1/16 diameter orsmaller. (Smaller diameters are easier to work with.)A damp sponge or cloth to wipe the hot top of the iron.A wire stripping tool fo