McIntosh MC 2100 User manual

THEMclNTOSHMC2100SOLIDSTATESTEREOPOWERAMPLIFIER
Price$1.25

YourMC2100stereoamplifierwill
giveyoumanyyearsofpleasant
andsatisfactoryperformance.If
youhaveanyquestionsconcerning
operationormaintenanceplease
contactthedealerfromwhom
youpurchasedthisinstrumentor:—
CUSTOMERSERVICE
MclntoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903
Phone:[phone]
TakeAdvantageof3 years
ofFREEFactoryService...
FillintheApplicationNOW.
CONTENTS
GUARANTEE
INSTALLATION
HOWTOCONNECT
CONTROLPANELINFORMATION
LISTENINGTOYOURSTEREOSYSTEM
PERFORMANCELIMITS
PERFORMANCECHARTS
TECHNICALDESCRIPTION
BLOCKDIAGRAM
.. . 1
.. . 2
...2,3
.. . 4
.. . 5
.. . 5
.. . 6
.. . 7
.. . 8
GUARANTEE
MclntoshLaboratoryIncorporatedguaranteesthis
Instrumenttobecapableofperformanceasadver-
tised.Wealsoguaranteethemechanicalandelec-
tricalworkmanshipandcomponentstobefreeof
defectsfora periodof90daysfromdateofpur-
chase.Ifsuchdefectsoccur,MclntoshLaboratory
oroneofitsauthorizedagencieswillrepairthe
defectatnocosttothepurchaser.Thisguarantee
doesnotextendtocomponentsdamagedbyim-
properusenordoesitextendtotransportationto
andfromthefactoryorserviceagency.
THREEYEARFACTORYSERVICECONTRACT
Anapplicationfora FREETHREEYEARFACTORY
SERVICECONTRACTisincludedwiththismanual.
Thetermsofthecontractare:
ForThreeYearsfromdateofpurchase—
1.Mclntoshwillprovideallparts,materialsand
laborneededtoreturnthemeasuredperformance
oftheinstrumenttotheoriginalperformance
limitsfreeofanycharge.TheSERVICECON-
TRACTdoesnotcoveranyshippingcoststoand
fromtheauthorizedserviceagencyorthefactory.
2.AnyMclntoshauthorizedserviceagencywillre-
pairallMclntoshinstrumentsatnormalservice
rates.Toreceivethefreeserviceundertheterms
oftheSERVICECONTRACT,theSERVICECON-
TRACTCERTIFICATEmustaccompanytheinstru-
mentwhentakentotheserviceagency.
3.Alwayshaveservicedonebya Mclntoshauthor-
izedserviceagency.Iftheinstrumentismodified
ordamaged,asa resultofunauthorizedrepairthe
SERVICECONTRACTwillbecancelled.Damage
byimproperuseormishandlingisnotcoveredby
theSERVICECONTRACT.
4.TheSERVICECONTRACTisissuedtoyouasthe
originalpurchaser.Toprotectyoufrommisrepre-
sentationthiscontractcannotbetransferredtoa
secondowner.
5.TheSERVICECONTRACTisgiventopurchasers
wholiveinthe50UnitedStatesorCanadaonly.
6.ForyourprotectionMclntoshselectsitsdealers
carefully.Onlyonedealerintenqualifiesfora
Mclntoshfranchise.ToreceivetheSERVICE
CONTRACTyourpurchasemustbemadefroma
Mclntoshfranchiseddealer.
7.YourcompletelyfilledInapplicationfora SERV-
ICECONTRACTmustbepostmarkedwithin30
daysofthedateofpurchaseoftheinstrument.
8.ToreceivetheSERVICECONTRACTallinforma-
tionontheapplicationmustbefilledin.The
SERVICECONTRACTwillbeissuedwhenthe
completelyfilledinapplicationIsreceivedat
MclntoshLaboratoryIncorporatedInBinghamton,
NewYork.Iftheapplicationisnotreceivedat
MclntoshLaboratory,onlytheserviceoffered
underthe90-dayguaranteewillapply.
Copyright© 1972ByMclntoshLaboratoryInc.
1

INSTALLATION
Adequateventilationextendsthetrouble-free
lifeofelectronicinstruments.Itisgenerallyfound
thateach10°centigrade(18°F)riseintempera-
turereducesthelifeofelectricalinsulationbyone
half.Adequateventilationisaninexpensiveand
effectivemeansofpreventinginsulationbreak-
downthatresultsfromunnecessarilyhighoperat-
ingtemperatures.Thedirectbenefitofadequate
ventilationislonger,trouble-freelife.
Thesuggestedminimumspaceformountingthe
MC2100is20inchesdeepx 9½incheshighx 12
incheswide.Alwaysallowforairflowbyeither
ventilationholesorspacenexttothebottomof
theamplifieranda meansforthewarmairto
escapeatthetop.
ItisrecommendedthattheMC2100bemounted
ina normalorhorizontalposition.Howeverwith
adequateventilation,theamplifiercanbemounted
inanypositionexceptupsidedown.Iftheampli-
fieristobeinstalledona verticalsurfaceitis
recommendedthattheautoformersbeonthe
downside.Thispositionpermitsgreaterairflow
aroundthetransistorsandcomponentpartsthere-
byextendingthetrouble-freelifeoftheamplifier.
HOWTOCONNECT
INPUT-STEREO
Theshieldedcablefromtheleftoutputofthe
Mclntoshpreamplifierispluggedintotheleftjack.The
shieldedcablefromtherightoutputoftheMclntosh
preamplifierispluggedintotherightjack.TheINPUT
switchmustbeintheSTEREOpositionandtheOUT-
PUTproperlyconnectedtothestereoloudspeakers
ordistortionandlossofpowermayresult.
INPUT-MONO
Theshieldedcablefromtheprogramsourceis
pluggedintotherightjack.TheINPUTswitchmust
beintheMONOpositionandtheOUTPUTproperly
connectedformonoloudspeakeroperationordistor-
tionandlossofpowermayresult.
OUTPUT-STEREOORTWINAMPLIFIERS
Forstereoortwinchanneloperationitisnotnec-
essarytousethesameimpedanceloudspeakeron
eachoutput.Simplyconnecteachchannelforthe
impedancedesired.
SPEAKERS
Speakersareconnectedatthebarrierstripsmarked
OUTPUTontheslopedpaneloftheamplifier.Use
lampcord,bellwire,orwirewithsimilartypeofinsula-
tiontoconnectthespeakerstotheamplifier.Forthe
normallyshortdistancesofunder50feetbetweenthe
amplifierandspeaker,#18wireorlargercanbe
used.Fordistancesover50feetbetweentheamplifier
andspeakeruselargerwire.
Theloudspeakerimpedanceisusuallyidentifiedon
theloudspeakeritself.Connectoneoftheleadsfrom
theleftloudspeakertothescrewmarkedCOMonthe
LEFTOUTPUTbarrierstrip.Connecttheotherlead
fromtheleftloudspeakertothescrewmarkedwiththe
numbercorrespondingtothespeakerimpedanceon
theLEFTOUTPUTbarrierstrip.Connectoneofthe
leadsfromtherightloudspeakertothescrewmarked
COMontheRIGHTOUTPUTbarrierstrip.Connectthe
otherleadfromtherightloudspeakertothescrew
markedwiththenumbercorrespondingtothespeaker
impedanceontheRIGHTOUTPUTbarrierstrip.
Theonlyadverseeffectontheoperationofa
Mclntoshamplifierwhenitisimproperlymatchedisa
reductionintheamountofdistortion-freepoweravail-
abletotheloudspeaker.Closeimpedancematchingis
desirableformaximumdistortion-freepower.
SPEAKERCONNECTIONS
Usethistabletodetermineproperspeakerconnec-
tion:
Connectthe
Ifthespeakerimpedancespeakerleads
isbetween:betweenCOMand:
3.2to6.5ohms4 ohms
6.5to13ohms8 ohms
13to26ohms16ohms
STEREOOUTPUT-CONNECTINGTOBARRIERSTRIPS
Usethistableforstereoconnectionsusingthe
barrierstrips:Connectoneright
Connectoneleftspeakerleadto
speakertoscrewthescrewmarked
IfthespeakerLEFT-COMandRIGHT-COMand
impedanceis:otherto:theotherto:
4ohmsLEFT-4RIGHT-4
8ohmsLEFT-8RIGHT-8
16ohmsLEFT-16RIGHT-16
For25voltlineoperationconnectoneoftheleftleads
tothescrewmarkedCOMontheLEFTOUTPUT
barrierstrip.Theotherleftleadisconnectedtothe
screwmarked8 ontheLEFTOUTPUTbarrierstrip.
Connecttherightleadsinthesamemanneronthe
RIGHTOUTPUTbarrierstrip.
WhenconnectedasabovetheMC2100operatesasa
105wattperchannelstereoamplifier.
2

MONOPHONICOUTPUT—CONNECTINGTO
BARRIERSTRIPS
WhentheNIC2100istooperateasa monophonic
amplifier,thetwochannelsarecombinedtoproducea
single210wattoutput.Thischartliststhepropercon-
nectionsandinterconnectionsformonophonicopera-
tion.
Ifthe
speaker
impedance
is:
2ohms
4ohms
Connectonespeaker
leadtothescrew
markedLEFT-COM
andtheotherto:
LEFT-4
LEFT-8
8ohmsLEFT-16
Forconstantvoltage
25volts LEFT-8
Connecta
wirebetween:
LEFT-4and
RIGHT-4
LEFT-8and
RIGHT-8
LEFT-16and
RIGHT-16
LEFT-8and
RIGHT-8
WhenconnectedasabovetheMC2100operatesasa
210wattperchannelmonophonicamplifier.
STEREOOUTPUT—CONNECTINGTO
THEOCTALSOCKET
TheoctalsocketmarkedOUTPUTcanbeusedforall
oftheoutputimpedancesandvoltages.Connections
aremadeinthefollowingfashion:
Ifthe
impedanceis:
Soldertheleft
channelleads
between:
4ohmsPin1 and2
8ohmsPin1 and3
16ohmsPin1 and4
Forconstantvoltage
25voltsPin1 and3
Soldertheright
Channelleads
between:
Pin5 and6
Pin5 and7
Pin5 and8
Pin5 and7
WhenconnectedasoutlinedtheMC2100operatesas
a105wattperchannelstereoamplifier.
MONOPHONICOUTPUT—CONNECTING
TOTHEOCTALSOCKET
Ifthe
impedanceis:
2ohms
4ohms
8ohms
25volts
CONNECT
2and6
3and7
4and8
4and8
Solderthe
leadsto:
1and2
1and3
1and4
1and4
WhenconnectedasoutlinedtheMC2100operatesas
a210wattmonophonicamplifier.
ACPOWER:
ThepowerrequirementfortheMC2100is117to130
volt,50/60Hz.Theamplifierwillbeturnedonandoff
ifitspowercordispluggedinoneoftheauxiliaryAC
poweroutletsontheprogramsource.
3

CONTROLPANELINFORMATION
INPUT
TheinputoftheMC2100hasa twopositionswitch
topermittheamplifiertobeusedinanyoneofthree
ways:
(1)Asa monophonic210wattamplifier.
(2)Astwin105wattamplifiersusedwithanelec-
troniccrossovernetwork,orastwocompletely
separateamplifiers.
(3)Asa stereoamplifierusedwitha Mclntoshpre-
amplifierorotherhighoutputstereoprogram
sources.
Ineitherpositionoftheinputswitchtheinputsensi-
tivityis0.5voltsforfullratedoutput.Theinputim-
pedanceis200,000ohms.
IntheSTEREOpositioneachinputiscontrolledby
aGAINcontrol.TheGAINcontrolallowssignal
sourcesof0.5voltupto30voltstobeconnectedwith-
outoverloadingtheinputtotheamplifier.
TheMONOpositionoftheinputswitchparallelsthe
inputsofbothamplifiers.Whentheoutputsareprop-
erlyconnectedtheMC2100becomesa 210wattmono-
phonicamplifier.TheRIGHT/MONOGAINcontrolper-
mitsconnectingsignalsourcesupto30voltswithout
overloadingtheamplifier'sinput.TooperatetheMC
2100asa 210wattmonophonicamplifiertheINPUT
switchmustbeintheMONOpositionandtheOUTPUT
mustbeproperlyconnectedformonophonicopera-
tion.
OUTPUT
ThetwobarrierterminalstripsmarkedLEFTOUT-
PUTandRIGHTOUTPUTprovidestereoconnections
forthenormalspeakerimpedancesof4 ohms,8 ohms,
and16ohms,ormonophonicoperationconnections
for2 ohms,4 ohms,and8 ohms.Theterminalstrips
mayalsobeconnectedfora constantvoltageoutput
of25voltsineitherstereoormono.
OUTPUT(OctalSocket)
TheoctalsocketmarkedOUTPUThasstereocon-
nectionsfor4 ohms,8 ohms,16ohms,and25volts.
Formonophonicoperationtheoctalsocketprovides
connectionsfor2 ohms,4 ohms,8 ohms,and25volts.
FUSE
TheMC2100usesa 5 ampereslo-blotypefuse.The
auxiliaryACoutletisnotfused.
ACOUTLET
TheauxiliaryACoutletcanbeusedtosupplypower
tootherequipmentinthesystem.Theoutletwillpro-
videa maximumof300wattsofpower.TheACoutlet
isnotfused.
LINEVOLTAGE
TheMC2100operatesonanylinevoltagebetween
117voltsand130volts,50to60Hz.
4

LISTENINGTOYOURSTEREOSYSTEM
SETTINGTHEGAINCONTROLS:
TosettheGAINcontrolsfora stereosystemusea
monophonicsignalfromtheprogramsource.A mono-
phonicsignalsuppliesthesamevoltagetobothchan-
nels.Turnthevolumecontrolonthesourceequipment
tothe12o'clockposition{halfrotation).
TurnuptheLEFTGAINcontroluntiltheloudness
intheroomisaboutasloudasyouliketolisten.Then
turntheGAINcontrolontheRIGHTINPUTuntilitis
equallyasloudastheleftchannel.Thesystemisnow
balancedforloudnessandprovidesthegreatestrange
ofoperationandloudnesschangewhenusingthevol-
umecontrolonthesourceequipment.
NOWSITBACKANDENJOYYOURMclNTOSH
PERFORMANCELIMITS
PerformanceLimitsarethemaximumdeviationfrom
perfectionpermittedfora Mclntoshinstrument.We
promiseyouthattheMC2100youbuymustbecapable
ofperformanceatorexceedingtheselimitsoryouget
yourmoneyback.Mclntoshistheonlymanufacturer
thatmakesthisguarantee.
POWEROUTPUT
STEREO:105wattscontinuous,perchannel,both
channelsoperating,whichis:
20.5voltsRMSacross4 ohms
29.0voltsRMSacross8 ohms
41.0voltsRMSacross16ohms
MONO—210wattscontinuous,whichis:
20.5voltsRMSacross2 ohms
29.0voltsRMSacross4 ohms
41.0voltsRMSacross8 ohms
HARMONICDISTORTION
STEREOWillnotexceed0.25%atanypowerlevel
to105wattsoutputperchannelfrom20Hzto20,000
Hzbothchannelsoperating.Typicalperformanceis
lessthan0.1%atratedpower.Distortiondecreases
asoutputpowerisreduced
MONOWillnotexceed0.25%atanypowerlevel
to210wattsoutputfrom20Hzto20,000Hz.Typical
performanceislessthan0.1%atratedpower.Dis-
tortiondecreasesasoutputpowerisreduced
INTERMODULATIONDISTORTION
STEREOWillnotexceed0.25%ifinstantaneous
peakpoweris210 wattsorlessperchannelwith
bothchannelsoperatingforanycombinationoffre-
quencies20Hzto20,000Hz
MONOWillnotexceed0.25%ifinstantaneouspeak
poweris420wattsorlessforanycombinationof
frequencies20Hzto20,000Hz
FREQUENCYRESPONSE
20Hzto20,000Hz+0-0.25dBatratedpower
15Hzto60,000Hz+0—0.5dBatratedpower
10Hzto100,000Hz+0-3.0dBatone-halfrated
power
NOISEANDHUM
90dBormorebelowratedoutput
OUTPUTIMPEDANCE
STEREO4,8,and16ohms
MONO2,4,and8 ohms
OUTPUTVOLTAGES
25voltsSTEREOandMONO
DAMPINGFACTOR
20at4 ohmsoutput
14at8 ohmsoutput
11at16ohmsoutput
INPUTIMPEDANCE
200,000ohms
INPUTSENSITIVITY
0.5volt.Levelcontrolprovidedforhigherinputvolt-
age
POWERREQUIREMENTS
120volts50/60Hz,50wattsatzerosignaloutput
450wattsatratedoutput
SEMICONDUCTORCOMPLEMENT
32silicontransistors
14siliconrectifiersanddiodes
MECHANICALINFORMATION
SIZE:7%incheshigh(19.69cm),11%incheswide
(29.85cm),17inchesdeep(43.18cm)
CHASSIS:Chromeandblack.
WEIGHT:57pounds(25.86kg)net,63pounds(28.58
kg)inshippingcarton
SPECIALFEATURES
Theamplifieriscompletelystablewhenconnected
toanyloudspeakersystemoreventoanyreactive
loads.TheMC2100hasspecialcircuitstoprevent
damagebyshortcircuitoropencircuitoftheoutput
loads,orbyanyamountofoutputimpedancemis-
match.
Thermalcutoutsaremountedontheoutputtran-
sistorheatsinkstoprovideprotectionintheeventof
inadequateventilation.
5

TECHNICALDESCRIPTION
Atwostagepreamplifierwiththreetransistorsin
eachchannelincreasestheinputvoltage16dB.
Thereare13transistorsineachpoweramplifiersec-
tion.Thetwostagepreamplifierisfedtoa pairof
matchedtransistorsarrangedasanemittercoupled
amplifierwithtwoinputsandoneoutput.Thesignal
fromthepreamplifiersectionconnectstooneofthese
inputs.BothACandDCnegativefeedbackareapplied
totheotherinput.Thislargequantityoffeedbackis
usedtoreducenoiseanddistortion.Thesignalisthen
fedtoa voltageamplifier.Thevoltageamplifierisfol-
lowedbytwodrivertransistors.
Theoutputsectionisarrangedasa seriespush-pull
amplifier.Thepowertransistorsusedintheoutput
sectionofyourMC2100areselectedfortheirhigh
powerdissipationcapability,widefrequencyresponse,
andlarge"safeoperatingarea."Inaddition,each
powertransistorisgivenfourseparatetestsbeforeit
isputinyourMC2100.Thisadditionaltestingmakes
sureyourMC2100willdeliveritsratedpowerfrom
20Hzto20kHzwithlowdistortionandcompletereli-
ability.
Thepowertransistorsaremountedonoversized
anodizedheatsinks.Theheatsinksassurethatunder
normaloperationthetransistorswilloperateata low
temperature.Iftemperaturesincreaseduetoa shorted
speaker,orrestrictedventilation,anautomatictem-
peraturesensingdeviceturnsofftheMC2100.The
deviceoperatesautomaticallyata presettemperature.
TheMC2100willturnonagainwhenthetemperature
hasreturnedtonormallimits.Thisadditionalfeature
givesyourMC2100completereliabilityunderthemost
extremeoperatingconditions.
Theoutputstagesarematchedtotheloadbythe
Mclntoshautoformer.TheMclntoshautoformeriscare-
fullywoundusingMclntoshtrifilarwindingandinter-
leavingtechniques.Trifilarwindingandinterleaving
givestheautoformersexceptionalbandwidth.The
autoformersproperlymatchthepowertransistorsto
4,8,and16ohmloadsatallaudiofrequencies.
TheuseoftheMclntoshdesignedtrifilarautoformer
makestheMclntoshsolidstateamplifierstheonly
amplifiersthatdeliverFULLPOWERATALLSPEAKER
IMPEDANCES.Youhavenotbeenpowerpenalizedfor
yourchoiceofloudspeakerswhenusingtheMclntosh
MC2100.
Anotheroftheadvantagesoftheautoformersisthe
25voltoutputfora constantvoltagedistributionsys-
tem.WiththeMC2100severalsetsofspeakerscanbe
operatedindependentlythroughoutyourhome.
Tofurtherinsurereliabilitya specialpoweroutput
SENTRYMONITORINGCIRCUITpreventsfailureof
thepoweroutputtransistorsduetoexcessivemis-
matchoftheoutput.WhenyourMC2100operatesnor-
mallytheSENTRYMONITORINGCIRCUIThasno
effectonsignalspassingthroughthepoweramplifier.
Ifthepowerdissipationshouldriseabovenormalop-
eration,theSENTRYMONITORINGCIRCUITrestricts
thedrivetotheoutputtransistors.TheSENTRYMON-
ITORINGCIRCUITactsinstantaneouslyforanyinput
signalorloadcombination.Thisarrangementassures
completecircuitreliability.OnlyMclntoshgivesyou
thisdegreeofprotection.
Therearethreeseparatepowersupplysections.One
positiveandonenegativehighcurrentsupplyisused
fortheoutputstages.Theotherpositivesupplyisused
forthedrivingamplifierstages.Allsuppliesarefull
waveandusesiliconrectifiers.Adequatefilteringis
usedtoassureanabsoluteminimumofhum.The
poweroutputstagefiltercapacitorshaveveryhigh
capacity,whichallowsfullpoweroutputbelow20Hz.
Thepowertransformerisgenerousinsizeandruns
cool,evenunderheavyuse.
7

MclNTOSHLABORATORYINC.
2CHAMBERSST.,BINGHAMTON,N.Y.13903
607-723-351 2
Designsubjecttochangewithoutnotice.
PrintedinU.S.A.
038-663