Hafler DH-200 User manual

THE
POWER AMPLIFIER
DH-200
INSTRUCTIONS
for ASSEMBLY
andOPERATION
929204
$3.00
THE DAVID HAFLERCOMPANY
5910CrescentBoulevard,Pennsauken, New Jersey08109
Please refertothisserial
numberinallcommunications
regardingthisequipment.

INTRODUCTION
The Hafler DH-200isatwochannelaudiopoweramplifier
designedtothevery highest performancestandards.Itis
availableeitherasa kit,orfullyassembled.Its100 watt per
channelpowerratingissufficientfor driving all
loudspeakersinhomeapplications,anditsdesignprovides
extremelylowdistortionof all types.A combinationofhigh
performance, dependabilityandreliability,andmoderate
price isinthe Hafler traditionofusingthe latest technology
toprovideoutstandingvalue.
Combining the latest power MOSFET technologywith
uniquely simple and effective circuit topologyreducesdistor-
tionofalltypes,andatallpower levels, overthe full audio
frequencyspectrum,tothevanishingpoint.Inadditiontoits
pace-settingperformanceachievements,theconservative
modeofoperationaccomplishesa newhighinlongterm
reliability andexceptionalresistancetoabusiveoperating
conditions. This isoneofthedirect benefits of MOSFET
utilization inovercominga seriouslimitationofconven-
tional transistors— theirtendencytoself-destructunder
otherthannormaloperatingconditions.Soruggedisthe
DH-200 thatitcandeliverasmuchastenamperesintoa
shortcircuit!
The speed— measuredasthe slew rate— ofthisdesign
deliversunmatchedtransientlinearity,revealingthemost
delicateshadings, textures andnuancesofthemusic,surpass-
ing thecapabilitiesofthemostrevealingloudspeakersand
cartridgesbyawidemargin.Coupledwithitsunconditional
stability,andabilitytodeliveradequatepowerintoany
loudspeakerload,theresultisabsolutefreedomfromlisten-
ing fatigue.Thelongeryoulistentothisphenomenal
amplifier, themorecertainyouwillbethatyoucouldnot
havemadea betterchoice.
Though modestin cost, theDH-200 evidences thevery
finestelectricalandmechanicaldesign.Itavoidscostlyfrills
and unnecessarygadgetrywhile providing qualitysoundand
reliability basedontopgradecomponentsconservatively
operated.
The oversizedpowertransformer and bridgerectifier;the
massive heat sinks;theconservativeoperating levels ofthe
MOSFET output devices — allareevidenceofthedesign
effortstoachieveexceptionalreliabilitysimultaneouslywith
state oftheart sonics andspecifications.Andthiscircuitis
convertible(withaninternalaccessorybridgingcircuit
board) toa highpowermonophonicamplifierwith
equivalentstabilityandspecifications.
The fullycomplementary,symmetricalpush-pullcircuit,
which isdirectcoupledthroughout (except attheinput),in-
corporatesallsilicon devices ina formatwhichisdirectly
relatedtothehighlyacclaimedDH-101preamplifier.Its
uniqueself-protectingoutput stage preventsthethermal
runaway whichisa commonthreattosolid state amplifiers.
The ruggednessandconservativeoperationoftheoutput
stage allowstheDH-200toavoidtheneedforspecialprotec-
tivecircuitswhichcouldcompromiseaudioperformance.
Basic protective systems providemaximumsecurityagainst
malfunction damagetotheamplifierorthespeaker:theAC
linefuse,B+ fuses, thermalbreakers, and loudspeaker fuses.
Nothing hinderstheessentialpurityoftheaudiosignal.
Thosewhouse these instructionsto assemble the
DH-200 kitwill find thatthe left andrightaudiomodules
(printed circuitand heat sink assemblies) arepreassembled
and pretested. This greatlysimplifiesthekitassemblysothat
itcanbedoneinonlya fewhourswithoutspecialskillsor
know-how.Becauseofthemodulararrangement,itispossi-
bletooperateononechanneliftheotherrequiresservice,
and obviatestheneedtoreturntheentireamplifierin cases
whereonechannelisinoperative.
Accessoriesforspecialapplicationsincludetheinput
bridging circuitboardformonophonicuse;a panelforstan-
dard 19" rack mounting;andanalternativepower
transformer forinternationalACline voltages.
Through advancedengineeringgearedtotheaudioper-
fectionist,andanefficientno-frillsapproach, Hafler ismak-
ing hightechnologyhighfidelityaffordable.
CONTENTS
Operation Page 3 AC Line Connections for Overseas Use12
Assembly Instructions 4 Kit Parts List 13
Wiring theKit6 Schematic Diagram 14
If Problems Arise 10 Component Value Listing 15
Service and Warranty 11 Pictorial Diagram Insert
© Copyright 1980. All rights reserved.
2

INSTALLATION
The DH-200ismostlikelytobeihstalledoutofsightin
mostapplications,sinceitspowermaybecontrolledbythe
AC switchingofmostaudiopreamplifiers,likethe Hafler
DH-101. Ifyourcontrolunit does notprovideswitching
capacitysufficientfortheamplifier's 5 amp needs (plusother
equipmentitis also switching),youshouldusetheamplifier's
ownpowerswitch.Inthat case, turn onthepreamplifierfirst;
then turn theamplifieronafew seconds after thepreamphas
beenturnedon,toavoidanyunnecessaryturn-ontransients
from some preamplifiers.Likewise,switchthepower
amplifier offfirst.
If theamplifieristobeinstalled close toa recordplayer,
you shouldfirst checkitspositionforfreedomfromhum
pickup bythecartridgefromthefield radiatedbythepower
transformer oftheDH-200.Althoughthedesignofthe
transformer minimizessuchradiation,certaincartridgesare
more sensitive thanothers,andrequireseparationfromthe
amplifier. Check atacomparativelyhighvolumesetting,and
whileswingingthe tone armthroughoutitsarc.Oftena few
inchesadditionalspacingwilleliminatetheproblem.
Be suretoprovidesufficient ventilation fortheamplifier.
Unobstructed air circulation aroundthefinned heat sinks
and above theamplifierisimportantforlong,trouble-free
life.Neverputanythingontopofthecoverperforations.Itis
normal forthetopandthe heat sinkstobecomewarminuse.
Itisexpectedthattheamplifierwillalwaysberestingon
its feet, whichshouldbeona hard enoughsurfacethatair
flow underneathisnotobstructed.Ifitismountedina rack,
or througha panel,the feet mayberemovedsolongasade-
quateventilationisprovidedthroughthebottomopenings.
OPERATION
The redpilotlampwhichisintegralwiththepower
switch glows whenevertheamplifieristurnedon.A blown
AC line fuse isthemostlikely cause ifitisnotilluminated
whentheamplifierisswitchedon.
The yellow lens isa hightemperatureindicator.Whileit
isnotlikelythatyouwilleverseeitlighted,ifitis,the
amplifier willnotproducesound.Itindicatesthatoneofthe
thermal breakershasshutdowntheamplifier because ofex-
cessive temperatureriseina heat sink. When the heat hasdis-
sipatedina fewminutes,theamplifiershouldreturntonor-
mal operation.Ifthelampagainlights,checkforinsufficient
ventilation,oran excessive inputsignal,oraninputwhich
mayhavedangeroussignalcontent(suchasoscillation).
Failing evidenceofthis,theamplifiermayhavemalfunc-
tioned.Becauseoftheverylarge heat sinks,itishighly
unlikely thatanynormalsignalwill cause theamplifierto
overheat.
Loudspeaker FuseSelection
The DH-200poweramplifierissuppliedwith2 amp
fuses inthespeakerlines.Experiencehasshownthatsincean
overload must exist fora few seconds fora fuse toblow,a2
amp fuse willprotectmostspeaker systems, andonlyblow
whenoverloadoccurs.Smaller fuses tendtoblowtooeasily,
and larger fuses donotadequatelyprotectmostspeaker
systems.
A pair of 5 amp fuses are also suppliedasalternativesfor
thespeaker fuse holders.Theseshouldbesubstitutedifthe
poweroutputoftheamplifieristobe tested, orifthe
amplifier istobeoperatedatveryhighpower levels into4
ohm loads.
If themanufacturerofyourspeakersrecommendsa
specificvalueof fuse fortheirprotection,we suggest thatyou
obtain3AG fuses ofthatvalueandsubstitutethemforthe
ones supplied.
Loudspeaker PowerRatings
There arenoU.S.standardsforratingthepowerhan-
dling capabilitiesofloudspeakers.Asa resultthemanufac-
turers' usual"musicpower"ratings,or suggested amplifier
limits, areofonly minimal helpindetermining safe operating
levels withamplifierswhichcandeliversubstantialamounts
of power.Youmusttakeintoconsiderationthetypeof
music,andthe levels youlike,toprovidelongtermtrouble-
freeoperationof your speakerchoice,whenyouhavea size-
ableamplifierliketheDH-200.
Connections
AC
TheAC powercordshouldbepluggedinto120volts,60
Hz, ontheswitchedoutputof a preamplifierwhichcan pro-
videat least 5 amps,or600 watts. Then theamplifierpower
switchmaybe left on,anditwillbecontrolledbytherestof
thesystem. Or, itmaybepluggedintoa 120voltwalloutlet,
and switchedonandoffindependently.
If yourlinevoltageisdifferent,besureyouhavethe
alternatepowertransformerwhichcanaccommodateseveral
line voltages, andbesureitis wired for your mainsvoltageas
describedlaterinthismanual before you plug in the
amplifier.
Input
Conventional shieldedcables,suchas those supplied
withyourpreamplifier,providetheinputsignaltothe
sockets onthebackpaneloftheDH-200.Besurethatthe
outershieldconnectionissecure,toavoidhum.Thelength
of these cables(soastopermitremotelocationofthe
amplifier, ifdesired)islimitedonlybytheoutputimpedance
of thepreamplifier.Ifitis1,000ohmsor less, aswiththe
DH-101, forinstance,cable lengths upto100 feet areper-
missiblewithout loss ofperformance.Speciallow.maci-
3

tancecablesenable even greaterdistance between preanip
and amplifier.Itisdesirabletokeepthe left andrightinput
cables close together throughouttheirlengthtominimizethe
likelihood ofhumpickup. Also, youshouldavoidrunning
themparallelto AC cords— these shouldbecrossedatright
angles.
Output
The loudspeakers(orheadphones)connecttothered
and blackterminalsinthecenterofthebackpanel.These
binding posts provideseveralconvenientalternativecon-
nectingmethods.Thescrewcapmayclampthebaredwire
end, ora "spadelug"attachedtoit,buta betterconnection
will bemadebylocatingthehole drilled throughtheshaftof
theterminalwhenthecapisunscrewed.Insertthetwisted
endofthebaredwiresothatthecapwillclampitinplace.
Always besurethatnostrandsofwireareunsecured,and
thatthebaredendisnottoolongto risk contactingother ele-
ments.A solderedendorfittingisthe safest solution.
Theseterminals also acceptstandardplug-in"bananapin
connectors,"includingthedouble ones withstandard3/4"
spacing,availablefromelectronicsupply houses. Theseare
themostconvenient,especiallyifyoumaywishtoin-
terchangespeakersoccasionally.
Itisimportanttomaintaincorrectphasingofthe
speakerswhenmakingtheirconnections.Somespeakerter-
minalsarecodedredandblack,or+ and—,etc.Itisim-
portantthatthe "sense" ofonespeaker'sconnectionsmatch
theothers.Ifoneisreversed,youwill find thatthesonicim-
agehas a "holeinthemiddle,"andthatitisdeficientinbass.
Speakerwirealwaysidentifiesoneconductortomakethis
easy. Theremaybea moldedridgeinonelead,orthecolor
of theinsulationononewireisdifferent,orthewireitself
maybecolorcoded.Ifpinplugsareused,besuretheyare
There arethreebasicrulesfor success inelectronickit
building:
1.Readtheinstructionscarefully,andfollowthemin
order.
2. Make securesolderconnectionswhicharebrightand
smooth.
3. Check yourworkcarefullyaftereach step.
The DH-200preamplifierisa versatilecomponentwith
sophisticated circuitry whichhasbeenmade remarkably easy
to build byindividualswithmanyyearsofexperienceinthe
designandengineeringofthefinestperformingaudiokits,
and inthepreparationoftheirmanuals.
Kit buildingshouldbefun,andwearecertainyouwill
find thistobeso.Assemblywillbefaster,easier,andmore
enjoyableif you have someone helpyoubyreadingthe steps
aloud, selectingtherequiredparts,and preparing the neces-
sarywire lengths inadvanceasyouproceed.Fatiguein-
creases the risk of error, sotakea breakratherthanpushto
early completion.Therearerelativelyfewseparatecompo-
nents inthisdesign,tomakeit easy topackeverythingaway,
if needbe.
color coded,orthatyoufollowtheindexing mark onone
side ofthedoubleconnectors.
Select speakerwireofsufficient size topreservethehigh
damping factor(and excellent speakercontrol)ofyour
amplifier. Standard18 gauge lampcord("zipcord")is
satisfactoryfor distances upto30 feet foran8 ohmspeaker.
As thedistanceincreases,largerwire sizes arerecom-
mended.The next largerwire size is#16,anditisoften
preferred byperfectionists.Ifyouhave4 ohmspeakers,the
maximum cablelengthfor best resultsishalved.
The blackoutputterminalsareelectricallyconnectedto
the chassis internally.Becertainthatwhentheamplifieris
operatedinitsnormal stereo modethattheredoutputter-
minalsare never connectedtogether.Inthespecial case when
theamplifierhasbeeninternallymodifiedformonophonic
bridged operation,theoutputistakenfromthetworedter-
minals only. Then, theblackterminalsare left unconnected.
Headphonesarenormallyoperatedfromtheloudspeaker
outputs,butareusuallyconnectedthrougha junctionbox
which providesswitchingfromphonestospeakers.Sucha
boxusuallyprovides some addedresistancetoreducethe
sensitivityofthephones,andthusminimizethelikelihoodof
hearing componentnoise, because ofthelowsettingre-
quired atthevolumecontrol.Someheadphone boxes utilize
a"common ground" system whichmakesit particularly im-
portantthatyoucarefullyobservetheproperconnections.
While theblackgroundterminals can beconnectedtogether,
thered ones mustnotbe.
Someheadphones,suchaselectrostatictypes,are less
sensitive andmayneedlittleornoresistancein series for
normal operation.Thesecouldbeeasilyinterchangedwith
thespeakersthroughtheuseofdoublebananaplugs.
Your workareashouldhavegoodlighting,theproper
toots, anda placewherethelargepictorialdiagramcanbe
tackedtothewallwithin easy reachforchecking.The tools
shouldinclude:
1.A 40to100 watt soldering iron witha 1/4"orsmaller
tipwhichreachesat least 600°F.
2. 60/40 (60%tin) ROSIN CORE solder,1/16"diameter
or smaller.
3.A damp sponge orclothtowipethehottipofthe iron.
4.A wirestrippingtoolforremovinginsulation. This can
bea single-edge razorblade,butinexpensivestripping
tools aresafer,fasterandeasier.
5.A medium-bladescrewdriver(about1/4"wide).
6. Needle-nose pliers(along,narrowtip).
7.Diagonalorside-cuttingsmallpliers.
8. Large "gas"or"slip-joint"pliers.
9.A 1/4""Spin-tite"nutdrivermaybehelpful,butisnot
necessary.
4
ASSEMBLY INSTRUCTIONS

A soldering"gun"isnot recommended.Theunfamiliar
userismorelikelytodamagetheetchedcircuitboardswith
itshigher heat potentialandunbalancedweight. Also,
because hemaynotwaitlongenoughforittoreachoperat-
ing temperatureeachtimeitisswitchedon,poorsoldercon-
nectionsaremorelikely.Pencilironsaremuchlighterand
easiertouse,andthereisnowaitingtimewhensoldercon-
nectionsfollowin sequence, asinkitbuilding. Make sure
you havea holderforit,though,andalwaysunplugitwhen
you takeabreak.
Proper Soldering
There arefour steps tomaking a goodsolderconnection:
1. Make agoodmechanicalconnectiontoholdthewirein
positionwhile heat andsolderisapplied.
2.Heat thejunction ofthewireandiug,or eyelet, withthe
bright, shinytipofthe iron.
3. After heatingfora couple seconds, applysoldertothe
junction. Itshouldmeltimmediatelyandflowsmoothly
around bothsurfaces.
4. Allow theconnectiontocoolundisturbed.
Remember thattheconnectionismadebythesolder,not
by mechanicallyattachingthewiretotheterminal.Usually
thewireisloopedthroughthelugandcrimpedinplace,but
some prefertojustplaceitthroughtheholeandrelyonthe
stiffness ofthewiretoholditwhilesoldering.Eyeletconnec-
tions,ofcourse,arehandledthisway.
Good solderconnectionsare essential fortrouble-free,
noise-freeoperation.A goodsolderjoint does notrequire
much solder around theconductors.Never "butter" partially
meltedsolderon the joint, asitis useless. Agoodconnection
lookssmoothandbright because thesolder flows intoevery
crevicewhenthepartsarehotenough.The iron musthavea
bright, shinytiptotransfer heat easilytothe junction. That's
whythedamp sponge shouldbeusedfrequentlytowipethe
tip, andoccasionallyyoumustadda smallamountofsolder
tothetip,too.Ifa connectionisdifficulttoheat,"wet"the
tipwitha smallblobofsoldertoprovidea biggercontact
surfacetothejoint.Oncethesolder flows aroundthecon-
ductors, anymovementmustbeavoidedforafew seconds to
allow a good bond. When cool,checktheconnectionbywig-
gling thewire.If ir. doubt,oriftheconnectionisnotshiny,
re-heatthe joint. Excesssoldermayberemoved from a con-
nectionbyheatingitandallowingthesoldertoflowontothe
iron, whichisthenwipedonthesponge.
ALL SOLDER USED MUST BE ROSIN CORE.
Never useacidcoresolderoranyseparatefluxin
electronicwork.Silversolderis also notsuitable.If in doubt
about unmarked solder,alwaysobtainafreshsupplyof rosin
coresolder.Werecommend 60/40 for easiest use.Donot
confuseitwith 40/60, whichishardertomelt.
The generalprocedureistouseahot iron forashorttime
to heat a connection,thenaddsolderwiththe iron stillin
contact.Removethesolder once itflows,andthenremove
the iron. A cooler iron appliedfora longertimeismore
likely todamagecomponents,orliftthecoppercircuitpat-
tern from theboards.A breakintheetchedcircuitcanbe
mendedbysimplysolderinga smallpieceofwireacrossit.
Do notallowmuchbuild-upofsolderonthetipofthe iron,
or itmay fall intoadjacent circuitry.
When solderingtoan eyelet onthe board, insertthewire
from thecomponentsside,andapplythe iron tothebottom,
leaving some barewireexposedsothatyoucanseethatthe
eyelet isthenfilledwithsolderfora securebond.A round
woodentoothpickis suggested sothatyoucan heat andclear
an eyelet ofsolderifithindersyourinsertingthewire.Some
builders prefertoclearevery eyelet firstwitha touchofthe
iron andtoothpick. Others connecttheleadby bringing itup
tothecenterofthe eyelet ontopofthe board, applyingthe
iron from thebottomof the board, and pushingtheleadinas
thesolderinthe eyelet melts.Ifthewirehasfirstbeen "tin-
ned," usuallynoadditionalsolderisnecessary,butitisa
goodpracticetopushthewire through, andthenbackitupa
bit, tobesuresolderfillsthe eyelet from both sides. Onthe
bottomofthe board, makecertaina bright, shinyflowisevi-
dent from thewire,acrossthe eyelet, ontothecircuitpattern
on the board. Itis essential thatthe eyelet befullysolderedto
the .circuitry, too.
"Tinning" referstotheprocessof applying a lightcoating
of soldertothebaredwireend. This keeps allthestrands
secured,and also makesa goodconnectioneasier.Simply
touchthewirewiththe iron fora couple seconds, andapply
solder. Allow the excess toflowawayontothe iron. When
properly done,thewireisuniformlybright,andnolarger
than before.Thehookupwiresuppliedwiththiskit does not
normally needtinning,foritispre-tinned.
5

Wiring theKit
Mechanical Assembly
If anycomponentsareunfamiliartoyou,checkingthe
pictorial diagram should quickly identifythem. Or, the quan-
tities,andtheprocessofeliminationasyouchecktheparts
list, will help.Thepictorialdiagramisnecessarilydistorted
to some extent for clarity, sothatyoucantraceeverywirein
a singleoverallviewforverificationasyouwork.Youmay
wishtocheckoff on the diagram asyousoldereachlocation.
To "prepare" a wiremeanstocutthedesignatedlength
from thecoilofthatcolor,andstripabout1/4"ofinsulation
from eachend.Thewiresuppliedinthekitis#18,soyou
can setadjustablewire-strippersaccordingly.The
transformer leadsare#16or18,andtheline cord is#18.
Be carefulthatyoudonotnickthewirewhenyoustripit
(that can happenmoreeasily if you donotusewirestrippers)
for that weakens it.Thewiresuppliedinthiskitis"bonded
stranded," whichprovidesexceptionalflexibilitywithresis-
tancetobreakageforeasieruse.
Whenever aconnectionistobesoldered,theinstructions
will so state, orindicatebythesymbol(S).If more thanone
wireistobesolderedtothesamepoint,they will be indi-
catedby(S-2),(S-4),etc.Ifsolderingisnotcalledfor,other
connectionshaveyettobemadetothatterminal. They
would bemoredifficultiftheconnectionwasalready
soldered. Every connectioninthekit will besolderedwhen
itiscomplete. After solderinga connection,itis best toclip
off any excess leadlengthtominimizethepossibilityofa
shortcircuit(asonswitchlugs,whereterminalsarevery
close together),andfor neatness.
Be surethatuninsulatedwirescannottouchadjacentter-
minalsorthe chassis metalwork.
The symbol(#)indicatesa connectionistobemadeto
thatpoint. When a lugnumberisspecifiedwithout(#),itis
simply a locatingreference.
When theinstructions call fortwistingtwoorthreewires
together,thelengthofwireindicatedanticipatesa fairly
tight, uniform twist by hand, ofthree full turnseverytwoin-
ches.If you find thewirestooshort,looseningthe twist will
gain some neededlength.
Handle the circuit boards carefully. They representa ma-
jor part ofthekit cost. Stand-up components,suchastransis-
tors,shouldbecheckedwhenyouinstallthemodule,tobe
sureallleadsareseparated.
All of the active circuitry iscontainedonthe PC-6 board,
which hasbeencarefully tested toassurethatit meets every
specification. Only theinterconnectionofpowersupply ele-
mentsislefttothe builder. Take thetimetobeaccurateand
neat,andyoucanbesurethatyourcompletedamplifier will
meet theperformanceofa factoryassembledunit,andcan
continueto perform properly foryearstocome. Check your
work, andmakesuretheentire step hasbeencompleted
beforeplacingacheck mark inthespace provided, andcon-
tinuing ontothenext step.
KEP nutshavebeensuppliedasa convenience.These
havelockwashersattached,andthelockwasheralways goes
ontothescrewfirst.Ifthe sheet metal screws havehexheads,
you may find iteasiertofirststartthemwitha regular
screwdriver, tosetthethread,andthenusethemorecon-
venientnut driver, ifoneisavailable.
1• When youunpackyourkit,you will find thatthe
transformer, largecapacitors,andtheoutputassem-
blieshavebeentemporarilyfastenedtothe chassis for
safe shipment.Disengage these, andincludethis hard-
warewiththerestwhenyoucheckoffthecomponents
againstthepartslistinthebackofthemanual.We
recommend thischeck-offtobesureyouhaveevery-
thing, andtoenableyoutoidentifyanyunfamiliar
itemsbycomparingthemwiththepictorialdiagram.
An egg carton isidealforkeeping hardware itemssepa-
rated.
A "set"ofhardwareincludesonescrewandone KEP nut
(withitsattachedlockwasher).Alwaysinstallthelockwasher
sideofthenutfirst.Ifthe size ofthehardwareisnot
specified,usethe#6size.Thesmallest size is#4and#10
thelargest.Alwaysinsertthescrew from theoutsideofthe
chassis.
It will simplifymattersif you firstseparatethe#4nuts from
the#6nuts,whichhavethesameoutsidedimensions.A #4
screw will pass througha #6nut,aidingidentification.
2• Selectthefourrubber feet, four sets of hardware, and
thechassis.Inserteachscrewthroughafootsothatthe
headisrecessed,andinstallthe feet ontheoutsideat
eachcornerhole.
3• Selectthetworedoutputterminals.Installtheminthe
sequence shownbelow,inthetwocenter holes R2and
R3 attherearofthechassis.Beforeyoufullytighten
thefirstnut,unscrewthecapto expose thehole drilled
through thethreadedshaft.Connectionofloudspeaker
wires will beeasierif these holes arepositionedver-
tically. A nail throughthehole will keepitpositioned
whilethehardwareistightened. Each connectinglug
should pointdownwardbeforethelastnutissecured.
Be surebothnutsoneachterminalaretight,asthey
aredifficulttoreachwhentheamplifieriscompleted.
4• Selectthetwoblackoutputterminalsandinstallthem
on eithersideof the red ones, atBlandB4.Besurethe
shaft holes arevertical,thelugspointdownward,and
eachnutistight.
5• Selectthetwo round fuse holders,andtwoeach1/2"
rubber washers,lockwashersandnuts. First installthe
rubber washerontheholder,soit will beoutsidethe
chassis,andthenfastenthe fuse holdersat LF and RF,
withthetiplugs pointing away from eachother,toward
the edge ofthechassis.
6

6• Selectthelarger round inputsocket,itsinsulatingdisc,
thesolderlugwithlockwasherteeth,two#4screws,
and thetwonylonnuts. This socket will beinstalledat
RS. Theinsideof the chassis at RS and LS hasnotbeen
painted, sothata goodgroundconnectioncanbe
made.Itmaybenecessarytocleanthiswitha solvent,
or withaneraser,beforethe sockets areinstalled.Place
thesolderlugonthelowermountingscrewinsidethe
chassis,followedbytheinsulatingdisc,thenthesocket.
Position thelugtowardthe edge ofthechassis.The
shorter ground lugonthesocketshouldalsobenearest
thisright edge. Securethissocketwiththenylonnuts.
7• Selecttheotherinputsocketandtwo sets of#4 hard-
ware.Installitat LS aftercleaningtheunpaintedarea,
withitsshortgroundlugneartheleft edge ofthe
chassis.
8• Selectthefour-lugrectifierblockRB,thelong#6
screw,anda nut.Installtherectifierinthecenterhole
neartherearofthechassis,withtheplus(+)terminal
locatedoverthetinyindexingholeatpositionfour.
Correct orientationofthisrectifierisessentialfor
proper wiring.
9• Selectthesingle fuse clip, andonesetof#4hardware.
Installtheclipintherightfront chassis hole FC, closest
tothefoot.
10• Selectthetwo dual fuse clipsandfour sets of#4 hard-
ware.Install these inthepairsof holes FL andFRon
eithersideofthecenterofthechassis.
11• Selectthetwo-lugterminalstripandonesetof#4
hardware. InstallitinthefrontholeTS,nexttothe
single fuse clip. Notethepositionofthemountinglug
(totheright)inthepictorialdiagram.
NOTE: Kits provided with the multiple voltage power transformer
for locations outside ;K- United States which usea line (mains)
voltage other than 120 VAC, are also supplied with a five-lug ter-
minal strip which is tobe installed in place of the two-lug strip, using
an additional set of #4 hardware near the dual fuse clip.
12• Selectthepowerswitch.If it says "Carting," positionit
with lug #3atthetop.If it says "Chicago," positionthe
small protruding plasticlugatthebottom.Snapitfully
intothefront chassis holePS from theoutside.
A soldering iron will beused regularly forinstallingthewir-
ing. Besureyouwipeitstipfrequentlywithadampclothor
sponge,asabrighttip will makeconnectionseasierwith less
likelihood ofoverheatingcomponents.Ifitisdifficulttoheat
a connectionina coupleofseconds,apply a small amountof
fresh soldertothetipsoitcanflowaroundtheconnection
and providegoodheattransfer.
Take thetimetoobservethedirectioneachwire takes from
itsconnectinglug,sothatwhenyouconnectthefirstend,it
will bepointingintherightdirection. This makesthejob
neater,andassuresthateachwireislongenough.
13• Preparea 6-1/2" greenwire.Connectoneendto dual
fuse clip FL lug# 1. Connecttheotherendtotheother
dual clipFRlug#1.(S).
14• Preparea 6-1/2" whitewire.ConnectoneendtoFR
lug #3.Connecttheotherendto FL lug#3.(S).
15• Selectthe2.2ohm(red-red-gold)resistor.Cuteach
lead to112"or less. Connectoneendtotheseparate
solderluginstalledunderinputsocketRS.(S). Con-
necttheotherendtotheshort(ground)lug#2of
socketRS.
16• Preparea 10"greenwireanda 10"whitewire.Twist
these togetheruniformly(aboutthreecomplete twists
everytwoinches).Connectthegreenwiretotheshort
RS lug#2.(S-2).ConnectthewhitewiretoRSlug
# 1. (S).Place these wiresoutof the way,overthe edge
of thechassis.
17• Selectoneofthe .0047 mfd film capacitors.Cuteach
lead to1/2",andconnectoneleadto fuse holderRF
lug # 1. ConnecttheotherleadtoRFlug#2.
18• Prepare two8"whitewires. Start with onewireproject-
ing 3/4"beyondtheother,and twist themuniformly
togetherthroughouttheirlength.Connecttheproject-
ing endtoRFlug#1.(S-2).Connectthecorrespond-
ing endof the otherwireto RF lug#2.(S-2).Placethis
pair overthe edge ofthechassis.
19• Prepare an11"whitewire and a 9" greenwire.Starting
withthewhitewire3/4"longerthanthegreenwire,
twist themtogethertowithinoneinchoftheotherend
of thegreenwire.Atthebeginningend,connectthe
greenwiretooutputterminallug#B4.Connectthe
whitewiretolug#R3.(S).Place these wiresofftothe
right.
20• Preparea 6"greenwire.Connectoneendtolug#B4.
(S-2).
21• Preparea 10"whitewireanda 10"greenwire.Twist
themtogether,andconnectthegreenwiretotheshort
LS lug#1.(S).ConnectthewhitewiretoLSlug#2.
(S).Place these wirestotheleft,overthe edge ofthe
chassis.
22• Selecttheremaining .0047 mfd film capacitor,andcut
eachleadto112".Connectoneleadto LF lug# 1, and
theotherleadto LF lug#2.
23• Preparetwo 7-1/2" whitewires.Startwithonewire
3/4"longer,and twist themtogetherthroughouttheir
length.ConnectthelongerendtoLFlug#2.(S-2).
Connect theotherwireto LF lug # 1. (S-2).Place these
wiresofftotheleft.
24• Preparea 9-1/2" whitewireanda 10"greenwire.
Starting withthewhitewire3/4"longerthanthegreen
wire, twist themtogetherto within oneinchof the other
end ofthewhitewire.Atthebeginningend,connect
thegreenwiretooutput terminal lug #B1. Connect the
whitewiretolug#R2.(S).Place these wiresofftothe
left.
25• Preparea6"greenwire.Connectoneendtolug#B1.
(S-2).
7

26 • Preparetwo20"whitewires,and twist them together
throughouttheirlength.Sixinchesinfromoneendof
the pair, cutoneofthewires,andunwinditabout
1-1'2" ineachdirectionfromthecut.Strip 1 4"of in-
sulationfromeachof these cutends.Placethelonger
portion ofthewirealongthelowerfront edge ofthe
chassis,withthebreakatthesingle fuse clip.Connect
onecutendto TS lug#2.Connecttheothercutendto
powerswitchlowerlug# 1. Theunbroken w ire ofthis
pair maybeplacedunderthepowerswitchforneat-
ness, andthefree ends projectfromthefrontcornersof
thechassis.
27 • Select thepowertransformer,four sets of1'2"long
#10hardware,andthefourflatwashers.Positionthe
transformer sothatthered leads emergenearthe
centerofthechassis.Theblackandblack/white leads
(andallofthebrown leads aswell,ifitisthemultiple
voltageversion)shouldprojecttowardthepower
switch.Besurenowiresarepinchedintheinstallation.
Placethewhitetwisted pair underthefront chassis lip.
Installa flatwasheroneachscrewthrougha
transformer footbeforethenutissecured.
The transformer leads canbetrimmedasdesiredfora neat
job, butbesureyoudonotcutanyof thern tooshort(panic
ularly ifthemultiplevoltageversionisused,andanychange
in thesupplyvoltageislikely). Cutting the leads tooshortfor
re-usemayvoidthetransformerwarranty,ifitisthoughtto
bedefective.Alternatewiringdiagramstortheoptional
multiplevoltageversionwillbefound elsewhere inthis
manual. Ifyouhavethattransformer,consultthembefore
wiring thetransformerandpowerswitch.
Be sureallstrandsofeachtransformerleadaretinnedand
soldered together beforeconnectiontoa lug,sothatthereis
no possibilityof a straystrandtouchinganythingbutthein-
tendedlug.
28 • ConnecttheblacktransformerleadtoPClug#2.
29 • Preparea 2"greenwire.ConnectoneendtoFClug
#2. (S-2). Connecttheotherendto PS toplug#3.(S).
30• Connecttheblack/whitetransformerleadtoTSlug
#2.
31 • Select theyellowlampassemblyandthespring steel
nut. Trim thelamp leads to2",andinstallitfromthe
outsideat HT. Thecenterofthenutcurvesawayfrom
the chassis whenitispressedoverthelamp case. Be
sureitispressedfullyhome,sothelampistight.
32D Connectonelead of thelampto TS lug#2. (S-3). Con-
nect theotherlampleadtoPSlowerlug#1.
33• Select the.005mfddisccapacitor,and trim its leads to
1/2"or less. ConnectoneleadtoPSlug#1. (S-3).
Connect theotherleadtoPSlug#2
34• Select theAClinecordandtheplasticstrainrelief.
Separatethetwoconductorsfor 2-1/2". Cut 1-1/2" off
of oneofthetwoleads,andstrip1/4"ofinsulation
from eachlead.Twistthestrandstightly,andtineach
end. Nine-and-a-halfinchesfromthe longest end,
makea sharp"V"inthecordbybendingitback
sharply on itself. Installthestrainreliefasshown,with
thesmallendofthestrainreliefnearestthestripped
endoftheline cord. Crimp thetwohalvesofthestrain
relief around thewireatthe "V" withheavypliers,to
partially formitbeforeinsertionintothebackpanel.
Then gripthelargerdiameterofthestrainreliefwith
thetipsofthepliers, squeeze ittightly,andinsertthe
endofthecordandthestrainreliefthroughtheback
panel hole AC, fromtheoutside.Notethattheholehas
aflatononeside,andthestrainreliefisinstalledac-
cordingly. Itsnapsintopositionwhenfullyinserted.
Placethelinecordundertheotherwires.
35• ConnectthelongerendofthelinecordtoPSlug#2.
(S-2). Connecttheshorterleadto FC lug#1.(S).
36• Select thetworedtransformerleads.Connectonelead
toRBlug#2.ConnecttheotherleadtoRBlug#3.
37• Select the.01mfddisccapacitor,and trim its leads to
3/4". Strip two1/2" pieces ofinsulationfromthewhite
wire, andslideonepieceovereachofthedisccapaci-
tor leads.ConnectoneleadtoRBlug#2. (S-2). Con-
nect theotherleadtoRBlug#3. (S-2).
38• Preparea 6"whitewire.ConnectoneendtoRBlug
#4.(S).Besurethisisthe(+)terminaloftherectifier.
39• Select oneoftheroundcapacitorbrackets,two sets of
#6hardware,oneofthe3/4"#10 screws anditsnut,
twoshort#10 SEMS screws (withlockwasherat-
tached),twosolderlugs,andoneofthelargecapaci-
tors.Inserttheshort screws throughthesolderlugs,
and installthemlooselyinthecapacitorterminals.In-
stallthelongscrewinthebracketclamp,notingthe
direction ofinsertioninthepictorialdiagram(to pro-
vide easy future access), andtightenthatnutabouthalf
way.Placetheassemblyinpositiononthechassis,on
8

therightside,nearestthepowerswitch.Installthetwo
sets ofhardwaretosecurethebrackettothechassis.If
thebracket twists asthe screws aretightened,firstin-
stallthecapacitor,andclampit. Make surethecapaci-
tor istightagainstthechassis,andthatitspositive( +)
terminal istowardthe right side ofthe chassis before
tighteningtheclamp.Positionthelugonthe(+ )ter-
minal (itwillbepaintedredifitisnotmarkedwitha
+) soitpointsforwardtowardthepowerswitch,and
tightenitsscrew.Pointthe negative terminallug
toward therectifierblocktotheleft,andtightenthat
screw. Make surenowiresaretrappedbythebracket.
40• Select theremainingcapacitor,itsbracket,two sets of
hardware, thelong#10hardware,thetwoshort#10
screws,andthetwosolderlugs.Installthisassemblyas
in thepreceding step, butbesurethepositivelugofthe
capacitorisnearestthecenter,pointingtowardthe
othercapacitor's negative lug.The negative lugofthis
secondcapacitorpointsforward.
41• Select thewhitewirefromRBlug4 (marked+ ) and
connectittoCRlug#2.
42• Preparea 4-3/4" whitewire.ConnectoneendtoFR
lug #3. (S-2). ConnecttheotherendtoCRlug#2.
(S-2).
43• Preparea 6"greenwire.ConnectoneendtoRBlug
#1.(S).Connecttheotherendto CL lug#1.
44• Preparea 4-3/4" greenwire.ConnectoneendtoFL
lug #1. (S-2). ConnecttheotherendtoCLlug#1.
(S-2).
45• Removealloftheinsulationfroma 2-3/4" whitewire.
Connect oneendto CL lug#2.(S).Connecttheother
endto CR lug#1.(S).
46• Connectthered/yellowtransformerleadtothecenter
of thebarewire between thecapacitorlugs.(S).
47• Connecttheseparategreenwirefromoutputterminal
Bl tothecenterofthebarewire, next tothe
transformer lead.(S).
48• ConnecttheseparategreenwirefromB4tothecenter
of thebarewirealso.(S).
49• Select theoutputassemblymodules(thetwomajor
items inthekit). You will note thattheonlydifference,
which identifiesthe left ortherightmodule,istheposi-
tionofthethermalbreaker,whichislocated between
one pair ofoutputtransistorsonthe heat sinkrib.
Beforeconnectingwiresto these modulesitis best that
you takethetimetomakeabsolutelycertainthateach
eyelet iswellsolderedtothecircuitryontheback(in-
side) ofthe board. Add a littlesolderifnecessary,butit
isimportantthatsolderflowfromthewire,acrossthe
eyelet, andontothe circuitry. Then if you wishtoclear
thecenterofthe eyelet foreasierinsertionofthewire,
usea roundwoodentoothpickafterheatingeach
eyelet. Nowpositiontherightmodule(withthe
breaker atthefrontwhenthelongrowof eyelets is next
tothe chassis) withthecircuitboardup,againstthe
chassis.
Wires willbeconnectedfromthetopotthe board, andthey
mustbesolderedtotheunderside. Even thoughtheconnect-
ing wireswillberatherlongwhentheamplifieriscompleted,
theyarejustlongenoughtoreachnow,soworkingroomis
limited. Itis best to heat the eyelet frombelowwhilethewire
isinsertedfromabove. That requires an iron withasmallflat
chiseltip—and some careonyourpart.Itis easiest tomelta
small blobofsolderonthetip,andpositionitunderthe
eyelet sothatthesolderblob,morethanthetip itself, isheat-
ing the eyelet. Ifthe eyelet isfirstfilledwithsolder,andthe
wireendpushedallthewaythroughtheheated eyelet first,
thenwithdrawnpartwayto expose a bitofthebareend
abovetheboardbeforethesoldercools,youshouldhavea
firmly solderedconnectionifit cools undisturbed.
Always tinawirethatistoconnecttoan eyelet. After solder-
ing, gobackandcheckbytwistingeachwire,tomakesure
nothing moves ontheother side ofthe board. Becareful,too,
thatyoudon'tloosenexistingconnections.toadjacent
eyelets. Fora bitbetter access to these connections,youmay
wishtoremovethethreemounting screws toallowthecircuit
board tobemoved,butdon'tforgetthenylonwashersunder
the board.
50• Select oneofthenarrownumberedstrips,andpeeloff
thebacking. This identifiesthe eyelet numbers,and
shouldbeplacedalongthebottomofthecircuit board,
with eyelet #14nearestthepowerswitch.
51• Preparea6"whitewire.Connectoneendto eyelet #4
of thecircuit board. (S).
52• Preparea 5-112" greenwire.Connectoneendto eyelet
#13.(S). Make sureitcannotcontactthetransistor
mountingscrewneartheunderside.
53• Select thegreenandwhitetwisted pair from theoutput
terminalsR3andB4.Connecttheshortergreenwireto
eyelet #6.(S).
54• Select the pair ofwhitewiresfromRF.Connectthe
shorterwireto eyelet #8.(S).Connecttheotherwire
to eyelet #11.(S).
55• Connecttheremainingwhitewirefromthegreenand
white pair fromtheoutputterminalsto eyelet #12.(S).
56• Connectthegreenwirefrom eyelet 13toFRlug#2.
(S).
57• Connectthewhitewirefrom eyelet 4 to FR lug #4.(S).
58• Select fourofthelong sheet metalscrews. Take careto
seethatnowiresarepinchedintheprocess,whileyou
tiltupandfastenthemoduletotheendofthechassis.
59• Select thegreenandwhite pair frominput socket RS.
Connect thewhitewiretothetoprear eyelet # 1.(S).
Connect thegreenwireto eyelet #2.(S). This pair will
bespecificallypositionedlater.
60• Select thewhite pair atthefront. Tuck the excess wire
intothecornerofthechassis,andconnectoneleadto
eachofthe lugs onthethermalbreaker.Soldereach.
9

61• Select the left outputmodule,makesureallits eyelets
arewellsoldered,andplaceitagainstthe left side of
thechassis,boardup,breakeratthefront.
62• Select the remaining stripof eyelet numbers, and install
itwith eyelet #3atthefront.
63• Prepare a 6-1/2" greenwire.Connectoneendto eyelet
#13.(S).Besureitcannottouchthetransistorscrew.
64• Preparea 5-1/2" whitewire.Connectoneendto eyelet
#4.(S).
65• Select thegreenandwhite pair from outputterminals
Bl andR2.Connecttheshorterwhitewireto eyelet
#12.(S)
66• Select thewhite pair from LF. Connectonewireto
eyelet #11.(S).Connecttheotherwireto eyelet #8.
(S).
67• Connecttheremaininggreenwirefromtheoutputter-
minal pair to eyelet #6.(S).
68• Connectthewhitewire from eyelet 4 to FL lug#4.(S).
69• Connectthegreenwirefrom eyelet 13to FL lug#2.
(S).
70• Select four sheet metal screws andfastenthemoduleto
thechassis,makingsurenowiresarepinched.
71• Select thegreenandwhite pair frominput socket LS.
Connect thegreenwiretorear eyelet #2.(S).Connect
thewhitewireto eyelet # 1. (S).
72• Tuck the excess oftheremainingwhite pair ofwires
intothe left frontcorner of thechassis, and connectone
wiretoeachlugofthethermalbreaker.Soldereach.
73• Select the5 ampslo-blo fuse (aslo-blo fuse hasdistinc-
tiveinternalconstruction)andinstallitinthesingle
fuse clip FC.
74• Select four5 ampregular fuses, andinstalltheminthe
dual fuse clips FL andFR.
75• Select thetwo2 amp fuses, andinstalltheminthe twist
type fuse holdersonthebackpanel.These fuses will
provide reasonableprotectionformostspeakers.See
the Operation sectionofthismanualformoredetailed
information. Theremaining5 amp fuses arealternates
for thebackpanelholdersforhighpower test pur-
poses.
76• For lowest distortionperformance,preciseplacement
of some wiresisimportant.Thewiresfromtheoutput
terminalsandthebackpanel fuse holdersshouldbe
keptagainstthechassis.Theyshouldbepositioned
overtotheinput socket, andthenstraightforwardto
the board. Theinput socket pairs shouldbe close tothe
chassis,butabovetheotherpairs,straighttothecenter
bottomofthecircuit board, andthenupthemiddleof
theboardabout1/2"out,rightintheplanedefinedby
the edges of the finned heat sinks. The wirestothedual
fuse clipsshouldbekeptawayfromtheboardand
againstthechassis,bringingthe excess lengthforward
of the fuses. The leads fromthepowersupplycapaci-
torsshouldbekeptawayfromeach board. Thegreen
leads from theblackoutputterminalstothepowersup-
ply shouldbebrought together throughoutmostof
theirlength.
77• Check allyoursolderedconnections— especially
those onthe fuse cliplugs,whichare sometimes
difficult tosolderto. Clip offany excess barewire
which couldshorttoadjacent lugs orthechassis.Pay
particular attentiontothestrandedwiresfromthe
transformer andline cord, andcheckthepowerswitch
connections.Now turn theamplifierupsidedownand
shakeoutanybitsofwireorsolder.
78• Slidethecoverinplace,andinstallitwiththe eight
sheet metalscrews.
79• Removethebacking from theserialnumberlabel,and
apply ittothebottomatthecenterrear.
CONGRATULATIONS!
YOU HAVECOMPLETEDONE OF THEMOST
TECHNOLOGICALLY ADVANCED AND SUPERB
SOUNDING AMPLIFIERSEVERDESIGNED.
IF PROBLEMSARISE
A greatdeal of carehas gone intoevery Hafler amplifier,
whetherkitorfactoryassembled,tobesurethatit meets or
exceeds allitsspecificationsbeforeitisshippedtoyou.Ev-
ery assembledamplifiermust pass a batteryofperformance
tests. Inthekit,eachoutputmoduleassemblywasin-circuit
tested tosimilarstandards.Since these modulescompriseall
of theactiveamplifier circuitry, save forthepowersupply,it
reducesthelikelihoodofaninternalproblemtonearzero,
withcarefulassembly.
Ifyou arecertaintheproblem lies inthepoweramplifier,
checkfirsttoseethattheredpilotlampislighted.Ifitison,
and theyellowlampislighted,thisindicatesthatthe thermal
safety breakerononechannelhasshutdowntheamplifier
because of excessive temperature.Inthis case, the heat sink
will beveryhottothetouch. After a fewminutestocool,the
amplifier willcommenceoperationautomatically.Ifitsoon
shuts downagain, and theamplifierhassufficientventilation,
themalfunctioniseitherinternal,ortheresultofanex-
cessive (andverylikelyinaudible)inputsignal.
If neitherlampislighted,themain fuse inthesingle fuse
clip onthe chassis isprobablyopen.If a replacement5am-
pere,Slo-Blo fuse also blows,theamplifier needs service,
and thereisa powersupplyproblem.
Ifa problem appearsonlyinonechannel of theamplifier,
itmaybeisolatedfromtherestoftheamplifierbyremoving
thepowersupply fuses tothatchannelintheadjacentdual
fuse clip.Theotherchannelmaythenbeoperated
monophonicalfy.The Hafler company does notencourage
local serviceofthisamplifier.Theoneadjustmentpoten-
tiometerissealedatthefactoryattheoperatingpointfor
lowest distortion,andyoushouldnotreadjustit.Thead-
10

vanceddesignofthiscircuitmeansthat some components
will notlikelybeavailablelocally,andalternativereplace-
ments arenotrecommendedatall.
We recommendthata defectiveoutputmodulebesepa-
rated fromtheamplifier,andreturnedforserviceatthefac-
tory. This reducesshipping weight andthelikelihoodof
damage,and enables youtooperatetheotherhalfifyou
wish.Inthis case, we suggest thattheconnectingwiresbeun-
solderedatthe eyelets; thateachwirebetaggedwiththe
eyelet number(visibleinsidethe board, alongthe edge — or
seetheboarddiagraminthismanual);thatthebarewire
ends allbeinsulated;thedualpowersupply fuses forthat
channelberemoved;andthewirestothatthermalbreaker
on the heat sinkfin bedisconnectedandtemporarily
soldered together, andinsulated.
SERVICE POLICY AND LIMITED WARRANTY
The DH-200Power Amplifier hasbeencarefully
engineeredtoprovidemanyyearsofusewithoutrequiring
anymaintenanceorservicing.
Factory assembledunitsaresubjectedtoseveralphysical
and electrical tests beforeshipment. The output circuit board
assemblies ofkitunitsaresimilarly tested prior toshipment.
In spite ofallthistesting,shippingdamage does occur,kits
arenotassembledproperlyor someone "goofs" andservice
and/or maintenancewillberequired.The David Hafler Co.
providescompleteservicefacilitiesatthefactorytomake
anynecessaryrepairs.
Itistheowner'sresponsibilityto return or ship the unit
freight prepaid to the factory service department. Units ship-
ped freight collectwill not be accepted. For units to be
repaired under warranty a copy of the dated bill of sale must
accompany the unit.
Shipmentshouldbemadevia UNITED PARCEL SER-
VICE. ParcelPostisnota safe waytoshipelectronicequip-
ment.Thefactorywillnotberesponsiblefordamagecaused
by parcel post shipmentandrepairswillbemadeatthe
owner's expense. WhenshippingyourDH-200besuretoin-
sureitforthe full valueofanassembledamplifier.
Usetheoriginalcartonandpackingmaterialtoshipyour
amplifier. Enclosewiththeunitthefollowinginformation:
1.Completeshippingaddress (Post OfficeBoxnumbers
areoftennotacceptable).
2.Theserialnumber.
3. Copy ofdated bill of sale if repairs aretobemadeunder
warranty.
4.Descriptionofthemalfunction.Ifintermittent, please
note.
5.We also suggest furtheridentifyingtheunitasyoursby
puttinga labelonthebottomortieinga labelwithyour
nameandaddressontheline cord.
All serviceworkisguaranteedfor90days.
Warranties applytotheoriginalpurchaseronly. Warran-
ties arevoidif:
1.Theamplifierhasbeeneitherphysicallyorelectrically
abusedorusedfor some purposeforwhichitwasnot
designed.
2.Theamplifierhasbeenmodifiedwithoutfactory
authorization.
The transformerwarrantyisvoidifthe leads havebeen
cuttooshortforreuse. Ifyou think a transformerisdefective
the leads mustbeunsoldered,notcut,foritsreturn.
Technical assistance tohelpyoulocatethesourceofa
problem maybeobtainedbywritingtheTechnicalServices
Department.Itishelpfultoknowtheserialnumberofthe
unit andtheresultsofany tests youhaveperformed.
SERVICING AN AMPLIFIERMODULE
If youarecertainthattheproblemisconfinedtooneof
theamplifiermodules(comprisingthecircuit board, heat
sink, andoutputtransistors),youmayremoveandreturn
onlythemoduleforservice.Besurethatthecomponentson
thecircuitboardarewellprotected— asbya surrounding
sleeve ofcorrugatedcardboardwhich rests againstthe heat
sink, andprojectsbeyondthecomponents.Properlypacked
and insuredfor$150,thisassemblycanbe sent byparcel
post,aswellas UPS, ifnecessary.A servicefeeof$20must
be sent with every module,sincethefaultmayhavebeen
causedbyawiring error elsewhere. For thisreason,too,and
because wehavenocontroloverits proper reinstallation,the
service warranty on a separatemoduleislimitedtoassurance
of itsproperfunctioningwhenit leaves theservicefacility.
All modulesare tested beforereturntoyou.Ifyoubelieve
thefaultisthefactory'swarrantyresponsibility,includethe
serial numberandthe bill of sale. Ifinourjudgementthe
faultisentirelya manufacturing defect, a portionoftheser-
vicefeewillberefunded. Only a completeamplifiercanbe
completelycheckedandgivena servicewarranty.
WARRANTYFORKIT-BUILT UNITS
The partsina DH-200kitarewarrantedfora full year
from thepurchasedate.If a defectivecomponentisfoundon
a circuit board orina kit,simply return the individual part to
thefactoryprepaid together withtheserialnumberandthe
dateofpurchase,anditwillbereplacedatnocharge.
If youcannotlocatewhatiswrongwithyourDH-200,
return ittothefactorywitha copyofthedated bill of sale,
and a checkfor$40.Ifthe sole cause ofthe problem isa de-
fectivepart,theunitwillberepairedandreturnedtoyou
transportation prepaid,andyour$40 less a charge for re-
packaging and shipping willbe returned to you. Ifthe prob-
lemisfoundtobean error inyourassemblyofthe ampli-
fier, theamplifierwillbeputinproperworking order, test-
edtobesureitismeetingspecifications,andreturnedto
you (freightprepaidwithinthecontinentalU.S.).Excess
shipping chargesforexpeditedservice,or overseas delivery
areyourresponsibility.Atthe sole discretionofthefactory
servicedepartment,ifthetimerequiredfordiagnosis,
repair andtesting,andthenatureofthemalfunctionwar-
rantsit,a portionofthesubmittedrepairfeemaybe
rebated.
This warrantyisvoidifthekithasnotbeencompletely
assembledorifotherthanrosincoresolderhasbeenused.
Units assembledwithacidcoresolderor paste fluxwillbe
returned unserviced.
WARRANTYFORFACTORYASSEMBLED UNITS
The DH-200iswarrantedfora full yearfrom the
purchasedateincludingpartsandlaborand normal shipping
costs fromthefactorytotheownerwithinthecontinental
U.S. Theownerisresponsibleforreturningtheunittothe
factoryandmustsubmita copyofthedated bill of sale.
This warranty gives youspecificlegalrights.Youmay
also haveotherrightswhichvaryfrom state to state.

AC LINE CONNECTIONS FOR OVERSEAS USE
The powertransformersuppliedinDH-200amplifiers
soldintheUSAisintendedfor120volt,60Hzoperation
only.Foruseinothercountries,a multi-voltagetransformer
isavailableathigher cost. Ithasdualtapped primary wind-
ings whichcanbearrangedinvariousseries-parallelcom-
binationsfor100,110,120,200,220and240volt50or60
cyclelines.Theschematicdiagram details thewiringcom-
binationswhicharerepresentedpictoriallyhere.
Notethata 5-lugterminalstripisrequiredwhenthe
multi-voltagetransformerisused. This, andthe 100,000
ohm resistorwhichis sometimes neededtoilluminatethe
pilotlamp,issuppliedinkitswhichincludethespecial
transformer. Iftheamplifierisoperatedwith200to240volt
lines,the5 ampline fuse whichissuppliedshouldbe
replacedwitha 2-1/2ampSlo-Blotype fuse.
12

KIT PARTS LIST
Minor variations maysometimes be encountered in value
or appearance.Thesewill not affect performance.
13
Fuse Envelope
Part No.
6 Fuse, 5 ampere 341050
1 Fuse, 5 ampere,Slo-Blo 342050
2Fuse, 2 ampere 341020
Hardware Envelope
Part No.
1 Lug, soldertype,internaltooth, #6 619308
4 Lug, soldertype, #10 629508
8 Nut, #4-40 KEP 614245
9 Nut, #6-32 KEP 614345
4 Nut, #10-32 KEP 614565
2Nut, #10-32 KEP, for clamp 614569
1 Nut,spring steel, Tinnerman type 610041
2Nut, #4-40 nylon 694241
2 Nut,1/2",forfuse holder 615074
10 Screw,machine, #4x 5/16"611255
8 Screw,machine, #6x 1/2" 611385
4 Screw,machine, #10x 1/2" 611585
2Screw,machine, #10x 3/4"
for clamp 611579
4 Screw, #10x 1/4", SEMS 611545
16 Screw, sheet metal, #6x 1/2" 612387
1 Screw,machine, #6x 3/4"611375
4 Washer,flat 7/8"616575
2Washer,locking,internaltooth,
1 /2" forfuse holder 617085
2Washer,rubber, 1/2"for
fuse holder 696081
1 Chassis 711007
1 Cover 711008
2Capacitor, 10,000 mfd, 75V294103
2Bracket,round, for capacitor 717058
1 Dioderectifierblock 544252
4 Feet,rubber 899757
2Fuseholder,round 351003
1 Fuseclip, single 351002
2Fuseclip,dual 352001
1 Indicatorlightassembly 526001
1 Input socket, round 351318
1 Input socket, narrow 351326
1 Insulatordisk,round, for socket 815318
1 Label, serialnumber 808005
1 Line cord, withplug 322001
2Outputmoduleassembly
(1 each, left andright) 994001
2Outputterminal,black,withhardware 351005
2Outputterminal,red,withhardware 351006
1 Powerswitch 332001
1 Strainrelief,plastic 895001
1 Terminal strip, 2 lug373181
alternate 5 lug for international use 377181
1 Transformer,power 464002
alternate for international use464003
1 Wire, white, #18
1 Wire, green, #18
1 Registrationcard
Small Parts Envelope part No.
1 Capacitor, .01 mfd,disc 238103
1 Capacitor, .005 mfd(5000M),disc 238502
2Capacitor, 0047 mfdfilm 264472
1 Resistor, 2.2 ohms 133022
2Numberedstrip, foreyelets808101

SCHEMATIC
DIAGRAM
© Copyright1980. All rightsreserved.

COMPONENT VALUES
Part No.
Rl
470,000 ohms
139474
R2
2,200 ohms
139222
R3
22,000 ohms
139223
R4
100 ohms
139101
R5
100 ohms
139101
R6
2,200 ohms
139222
R7
2,200 ohms
139222
R8
330 ohms
139331
R9
22 ohms
139220
RIO
22 ohms
139220
Rll
39,000 ohms
139393
R12
560 ohms
139561
R13
39,000 ohms
139393
R14
560 ohms
139561
R15
22 ohms
139220
R16
22 ohms
139220
R17
2,200 ohms
139222
R18
330 ohms
139331
R19
2,200 ohms
139222
R20
100 ohms
139101
R21
100 ohms
139101
R22
22,000 ohms
139223
R23
2,200 ohms, 1 watt
136222
R24
560 ohms
139561
R25
100 ohms
139101
R26
1,800 ohms
139182
•R27
100 ohms
139101
R28 47
ohms, carbon comp.
119470
R29
1,000 ohms
139102
R30
470 ohms
139471
R31
220 ohms, 112watt
133221
R32
1,800 ohms
139182
R33
100 ohms
139101
R34 47
ohms, carbon comp. 119470
R35
2,200 ohms, 1 watt
136222
R36
1 ohm, 5 watt,10%w.w.
120010
R37
10 ohms
139100
R38
10 ohms, 2 watt 190100
R39
0.5 ohms, 1/2watt 133509
R40
220 ohms, 1/2watt
133221
R41
220 ohms, 1/2watt
133221
R42
220 ohms, 1/2watt
133221
R43
220 ohms, 112watt
133221
R44
100,000 ohms, 1/2watt 133104
R45
2.2 ohms, 112watt
133022
PI
1,000 ohms trimpot 100102
Fl
Fuse 5A Slo-Blo 3AG
342050
F2 Fuse 5A,3AG
341050
F3 Fuse 5A,3AG
341050
F4
Fuse 2A,3AG
341020
Tl Power Transformer
464002
T2
Power Transformer,
International
464003
CI 10 mfd, 16V, non-polarized
electrolytic
203106
C2
390 pF, 500V, Mica 257391
C3 0.001mfd, 100V,Film
264102
C4
0.001mfd, 100V,Film 264102
C5 470 mfd,6.3V, non-polarized
electrolytic
202477
C6 270 pF, 500V, Mica 257271
C7
100 mfd, 80V, Electrolytic
294107
C8
0.1mfd, 100V,Film
264104
C9
680 pF, 500V, Mica
257681
C10
100 mfd, 80V, Electrolytic
294107
Cll 0.01mfd, 100V,Film 264103
C12
0.1mfd, 100V,Film
264104
C13 390 pF, 500V, Mica
257391
C14 0.005 mfd, 1000V, Disc 238502
C15
0.01mfd, 1000V, Disc
238103
C16
10,000 mfd,75V, Electrolytic 294103
C17
10.000 mfd.75V. Electrolytic 294103
C18
680 pF, 500V, Mica
257680
C19
0.0047 mfd,100V,Film 264472
C20 0.01mfd, 100V,Film 264103
C21 0.01mfd, 100V,Film
264103
Dl
1N4148
544148
D2
1N4148
544148
D3
1N4148
544148
D4
1N4148
544148
D5
1N4148
544148
D6
1N4148
544148
D7
1N4148
544148
D8
1N5240B
540510
D9
1N5240B
540510
D10
1N4148
544148
Dll
1N4003
544102
D12
1N4003
544102
D13
1N4003
544102
D14
1N4003
544102
DB1
Diodebridge
544252
Ql
2N5550
572550
Q2
2N5550
572550
Q3
2N5550
572550
Q4
2N5401 562401
Q5
2N5401 562401
Q6
2N5401 562401
Q7 2N5401
562401
Q8
2N5415
562415
09
NP2222 572222
Q10 2N5550
572550
Qll
2N3440
572440
Q12 2N3440
572440
Q13
2N5415
562415
Q14
2SK134
571134
Q15
2SK134
571134
Q16
2SJ49
561049
Q17
2SJ49
561049
15
All resistors are 1/4 watt 5%carbon film unless otherwise noted.

SPECIFICATIONS
Power Rating:Lessthan0.02%totalharmonicdistortion
atanypower level upto100 watts continuousaverage
powerperchannelinto8 ohmsatanyfrequency bet-
ween20Hzand20kHz with bothchannelsdriven.
IM Distortion (SMPTE):Lessthan0.005"*from1 watt
to100 watts into8 ohms.
TypicalTHDat100 watts into 8 ohms:
1kHz— 0.0015%
10kHz— 0.005^
20kHz— 0.012^
Frequency Response into 8 ohms:
- 3 dB,1 Hzto100kHzat1 watt
±0.5dB, 10Hzto40kHzat100 watts
TypicalChannel Separation: 20Hz:66dB
1kHz:66dB
20 kHz: 60dB
Signal to Noise Ratio, unweighted: Betterthan100dB
at100 watts into8 ohms.
Input Impedance: 22,000ohms.
Input Sensitivity: 1.5voltsrmsfor100 watts into8 ohms.
DampingFactor:150to1 kHzinto8 ohms
50to10kHzinto8 ohms
Rise Time:10kHz,60voltspeaktopeak square wave,
\09< to 907c : 2.5/is.
Slew Rate: 10 kHz, 60voltspeaktopeak square wave:30
V/M s.
Semiconductor Complement: 26transistors,8 power
Mosfets, 24diodes,4 zenerdiodes,1 diodebridge.
Power Consumption: Quiescent:101) VA; 100 watts into
8ohms:370 VA.
Size: 5-1/8"high,16"wide,10-1/2"deep.
Net Weight 26lbs. Shipping Weight: 30lbs.
16
All Specificationsaresubjecttochangewithoutnotice.

HAFLER DH-200 STEREOPOWER AMPLIFIER
PICTORIAL DIAGRAM
POWERTRANSFORMER
120 Volt ACLine
Connectionsshown
OUTPUTMODULEASSEMBLY
©COPYRIGHT 1980. ALL RIGHTS RESERVED