McIntosh C32 User manual

THEMclNTOSHC32SOLIDSTATESTEREOPREAMPLIFIER
ReadingTime:44MinutesPrice$1.25

WARNING:TO PREVENTFIREOR SHOCK
HAZARD,DONOTEXPOSETHISUNITTO
RAINORMOISTURE.
TheMclntoshyouhavepurchasedhasa serialnumberlocatedon
therearpanelofthechassis.
Recordthatserialnumberhere
forfuturereferences.Themodelandserialnumberareimportant
toyouforanyfutureservice.

YourC 32StereoPreamplifierwill
giveyoumanyyearsofpleasantand
satisfactoryperformance.Ifyou
haveanyquestions,pleasecontact:
CUSTOMERSERVICE
MclntoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903
Phone:[phone]
TakeAdvantageof3 years
ofFREEService...
FillintheApplicationNOW.
Contents
INTRODUCTION2
HOWTOINSTALL2
HOWTOCONNECT4
USINGTHEFRONTPANELCONTROLS8
USINGTHEPUSHBUTTONS11
BALANCINGYOURSTEREO12
LISTENINGTOYOURSTEREO12
PERFORMANCELIMITSANDRATINGS13
PERFORMANCECHARTS14,15
TECHNICALDESCRIPTION16
BLOCKDIAGRAM19
THREEYEARSERVICECONTRACT
Anapplicationfora FREETHREEYEARSERVICECONTRACTisincludedwiththismanual.
Thetermsofthecontractare:
1.Mclntoshwillprovideallparts,materialsand
laborneededtoreturnthemeasuredperfor-
manceoftheinstrumenttotheoriginalper-
formancelimitsfreeofanycharge.The
SERVICECONTRACTdoesnotcoverany
shippingcoststoandfromtheauthorized
serviceagencyorthefactory.
2.AnyMclntoshauthorizedserviceagency
willrepairMclntoshinstrumentsatnormal
servicerates.Toreceivethefreeservice
underthetermsoftheSERVICECONTRACT,
theSERVICECONTRACTCERTIFICATEmust
accompanytheinstrumentwhentakento
theserviceagency.
3-Alwayshaveservicedonebya Mclntosh
authorizedserviceagency.Iftheinstrument
ismodifiedordamaged,asa resultofun-
authorizedrepairtheSERVICECONTRACT
willbecancelled.Damagebyimproperuseor
mishandlingisnotcoveredbytheSERVICE
CONTRACT.
4.TheSERVICECONTRACTisissuedtoyouas
theoriginalpurchaser.Toprotectyoufrom
misrepresentationthiscontractcannotbe
transferredtoa secondowner.
5.ForyourprotectionMclntoshselectsonly
dealerswhohavetechnicalcompetenceto
guidepurchasersfairly,andprovideservice
whennecessary.ToreceivetheSERVICE
CONTRACTyourpurchasemustbemade
froma Mclntoshfranchiseddealer.
6.Yourcompletelyfilledinapplicationfora
SERVICECONTRACTmustbepostmarked
within30daysofthedateofpurchaseofthe
instrument.
7.ToreceivetheSERVICECONTRACTallin-
formationontheapplicationmustbefilled
in.TheSERVICECONTRACTwillbeissued
whenthecompletelyfilledinapplicationis
receivedatMclntoshLaboratoryIncorporated
inBinghamton,NewYork.
Copyright© 1977byMclntoshLaboratoryInc.
1

Introduction
TheMclntoshC 32preamplifierprovidesthemostcom-
prehensiverangeoffunctionsandcontroloptions.Many
ofthesearenewina preamplifier.TheC 32canonly
serveyoubestwhenyouunderstandwhatitsfunctions
areandwhatitisdesignedtodo.Spendsometimewith
thismanualandgettoknowhowthispreamplifierworks.
TheC 32isa "dual"stereopreamplifierwitha built-in
MONITORPOWERAMPLIFIER.Therearetwototallyinde-
pendentleftandrightstereoprogramlinesrunning
throughthepreamplifier.OneprogramlineistheLISTEN
programline,theotheristheRECORDprogramline.Each
programlinecanselectitsownprogramsourcefromany
connectedinputsignal—i.e.PHONO,TUNER,AUX,or
TAPES1,2 or3 withoutinterferencewiththeotherpro-
gramline.
TheoutputoftheLISTENprogramlineisaffectedby
allthefrontpanelcontrols(excepttheRECORDswitch)
andisfedtotheOUTPUTMAINand/orOUTPUT1 and2
jacksasselectedbyfrontpanelpushbuttons.Theoutput
oftheRECORDprogramlineisnotaffectedbyfrontpanel
controls(excepttheRECORDswitch)andisfedtoall
OUTPUTRECORDjacks.
TheMONITORAMPLIFIERprogrammaybeselected
fromeithertheLISTENorRECORDprogramlines.Sepa-
rateGAINcontrolsforLEFTANDRIGHTMONITORAM-
PLIFIERarelocatedonthetoppanel.Thesignalselected
fortheMONITORAMPLIFIERisfedtothefrontpanel
HEADPHONEjacksandtherearpanelOUTPUTLINEand
MONITOROUTPUTconnectors.
Howtoinstall
ThePANLOCsystemofinstallingequipmentconve-
nientlyandsecurelyisa directresultofMclntoshresearch.
BydepressingthetwoPANLOCbuttonsonthefrontpanel
oftheC 32,theinstrumenteithercanbelockedfirmlyin
placeorunlockedsothatthechassiscanbeslidforward,
givingyoueasyaccesstothetopandrearpanels.
Thetrouble-freelifeofanelectronicinstrumentis
greatlyextendedbyprovidingsufficientventilationto
preventthebuildupofhighinternaltemperaturesthat
causedeterioration.Allowenoughclearancesothatcool
aircanenteratthebottomofthecabinetandbevented
fromthetop.Withadequateventilationtheinstrument
canbemountedinanyposition.Therecommendedmini-
mumspaceforinstallationis15inches(38.1cm)deep,
17inches(43.2cm)wide,and6 inches(15.2cm)high.
Toinstalltheinstrumentina Mclntoshcabinet,follow
theinstructionsthatareenclosedwiththecabinet.For
anyothertypeofinstallation:
1.UnpackfromCarton
RemovetheinstrumentPANLOCbrackets,hardware
package,andmountingtemplatefromthecarton.Re-
movetheC 32fromitsplasticbagandplaceitupside
downontheshippingpallet;unscrewthefourplastic
feetfromthebottomofthechassis.
2.MarkforPosition
Placethemountingtemplateinpositiontocoverthe
areaofthecabinetpanelwheretheinstrumentistobe
installed,andtapeitinplace.Thebrokenlinesthat
representtheoutlineoftherectangularcutoutalso
representtheoutsidedimensionsofthechassis.Make
suretheselinesclearshelves,partitions,oranyequip-
ment.Withthetemplateinplace,firstmarkthesixA
andB holesandthefoursmallholesthatlocatethe
cornersofthecutout.Then,jointhefourcornermark-
ingswithpencillines,usingtheedgeofthetemplate
asa straightedge.
2

3.DrillHoles
Usinga drillwitha 3/16inchbitheldperpendicularto
thepanel,drillthesixA andB holes.Then,usinga drill
bitslightlywiderthanthetipofyoursawblade,drill
oneholeateachoftwodiagonallyoppositecorners.The
holesshouldbarelytouchtheinsideedgeofthepencilled
outline.Beforetakingthenextstep,makesurethat
thesixA andB holeshavebeendrilled.
4.SawPanelCutout
Sawingcarefullyontheinsideofthepencilledlines,
firstmakethetwolongcutsandthenthetwoshort.
Aftertherectangularopeninghasbeencutout,usea
filetosquarethecornersandsmoothanyirregularities
inthecutedges.
5.InstallMountingStrips
Inthehardwarepackageyouwillfindtwomounting
stripsandtwosetsofmachinescrews.Forpanelsthat
arelessthan½ inchthick,usethe¾ inchscrews;for
panelsthataremorethan½ inchthick,usethe1¼inch
screws.
Startingattheright-handsideofthepanel,inserta
screwoftheproperlengthintothecenterholeinthe
panel,markedB onthetemplate.Onthebackofthe
panel,aligna mountingstripwiththeholesinthepanel
andtightenthescrewuntilthescrewheadispulled
slightlyintothewood.
Repeatthisproceduretoattachthemountingstrip
totheleftsideofthepanel.
6.AttachPANLOCBrackets
UsingtwoscrewsoftheproperlengthintheA holeson
eachside,attachthePANLOCbracketstothecabinet
panel;theshortflangeismountedagainstthefront
(face)ofthecabinetpanel.Thescrewspassthroughthe
PANLOCbracketflange,thecabinetpanel,andthen
throughthemountingstripspreviouslymounted.
7.InstallInstrument
GuidetheACpowercordthroughthepanelopeningto
thebackofthecabinet;then,slidetheinstrumentinto
theopeningcarefullysothattherailsonthebottomof
eachsideofthechassisengagethetracksonthemount-
ingbrackets.Continuetoslidetheinstrumentintothe
cabinetuntilitisstoppedbytheadjustpositionlatches.
Pressthelatchesinward,thispermitstheinstrumentto
slideintothecabinetuntilitsfrontpanelisflushwith
thecabinetpanel.DepressthePANLOCbuttonsatthe
lowerleftandrightcornersoftheinstrumentpanelto
locktheunitfirmlyinthecabinet.Depressingthe
PANLOCbuttonsagainwillunlocktheinstrumentso
thatitcanbeslidforwardtotheadjustposition;
pressinginwardontheadjustpositionlatchespermits
removalfromthecabinet
3

HowtoConnect
CONNECTINGA TURNTABLETOPHONO1
Connect the cablefrom the "left" channel ofthe turn-
tableintotheINPUTL PHONO1 jack.
Connectthecablefromthe"right"channeloftheturn-
tableintotheINPUTR PHONO1 jack.
PHONO2 isprovidedfortheuseofa secondturntable.
Connectthecablefromthe"left"channeloftheturn-
tableintotheINPUTL PHONO2 jack.
Connectthecablefromthe"right"channeloftheturn-
tableintotheINPUTR PHONO2 jack.
OntherearpanelaretwogreenACpoweroutletsand
aslideswitchmarkedAUTO/MANUAL.PlugtheACpower
cablesfromtheturntableintothegreenTURNTABLE
POWERoutletson therearpanel.Whentheswitchis in
theAUTOposition,powertotheblackACpowerout-
lets,canbecontrolledbythefrontpanelPOWERswitch
orbythecurrentdrawnbya turntablepluggedinto
thegreenTURNTABLEPOWERoutlets.Thecurrentsens-
inggreenACpoweroutletswillcontroltheACpower
totheentiresystemfromtheACpoweron/offswitchon
theturntable.Whentheturntableisturnedoffwithits
ownACpowerswitch,nocurrentisdrawnwhichcauses
thecurrentsensingrelaysintheC 32toturnoftallAC
powertothesystem.WiththeAUTO/MANUALswitchinthe
MANUALposition,ACpowertothesystemwillbecontrolled
bythefrontpanelPOWERpushbuttononly.
Someturntableshaveelectroniccircuitsthatdrawcurrent
allthetime.TousetheseturntablestheAUTO/MANUAL
switchmustbeintheMANUALposition.
ThegreenACpoweroutletsareprotectedwitha one
amperefuse.Anyincreaseinthevalueofthisfusewill
affecttheoperationofthesensingcircuitandcancause
severedamage.
GROUNDCONNECTION
Asinglegroundpostisprovided.Groundsforturntables,
recordchangers,tapedecks,etc.shouldbeconnectedto
thispost.Theleftandrightprogramcablesandtheground
wirefromthatsourceshouldbewoundortwistedtogether.
Toavoidhum,makesurethegroundwiredoesnotmake
anyconnectionstotheshieldsoftheleftandrightprogram
cablesbetweentheprogramsourceandtheC 32.
CONNECTINGA STEREOTUNER
Connectthecablefromthe"left"channeltuneroutput
totheINPUTL TUNERjack.
Connectthecablefromthe"right"channeltuneroutput
totheINPUTR TUNERjack.
AUX—Anyhighlevelprogramsourcesuchasa tuner,
aTVsetora taperecordercanbeconnectedtotheINPUT
AUXjacks.
CONNECTINGTAPERECORDERS
ToRecord:
Connecta cablefromtheOUTPUTL TAPE1 jacktothe
lefthighlevelinputofthetaperecorder.
Connecta cablefromtheOUTPUTR TAPE1 jacktothe
righthighlevelinputofthetaperecorder
Connectsecondandthirdtaperecordersinthesame
fashiontotheTAPE2 andTAPE3 outputs.
ToPlayback/Monitor:
Connectthecablefromtheleftchanneloutputofa tape
recordertotheINPUTL TAPE1.
Connectthecablefromtherightchanneloutputofa tape
recordertotheINPUTR TAPE1.
Connectsecondandthirdtaperecordersinthesame
fashiontotheTAPE2 andTAPE3 INOUTjacks.
TAPERECORDERFRONTPANELCONNECTION
InputsandoutputsforTAPE3 areavailableattheTAPE3
IN-OUTjacksonthefrontpaneljustleftofthepushbuttons.
Thisallowsrapid,temporaryconnectionstoTAPE3 position
withoutgettingattherearpanel,A metalshieldedV
stereophoneplugisusedforbestshielding—similarto
theplugsusedonlowimpedanceheadphones.Connections
followtheindustrystandardsandaretip:leftsignal,ring:
rightsignal,and,sleeve:commonground
Connectinga TapeRecordertotheListenProgramLine
Connecta cablefromtheOUTPUT1 —LEFTjacktothe
lefthighlevelinputofthetaperecorder
Connecta cablefromtheOUTPUT1—RIGHTjacktothe
righthighlevelinputofthetaperecorder.
Outputsignalwillbetedtothetaperecorderwhenthe
frontpanelpushbuttonOUTPUT1 ispushedin.
CONNECTINGTHEC 32TOPOWERAMPLIFIERS
ConnecttheOUTPUTMAINjackstotheinputofa
stereopoweramplifier.TheLeftMAINjackisconnected
totheleftamplifierinputjack.TheRightMAINjackis
connectedtotherightamplifierinputjack.
Twoadditionalstereopoweramplifiersmaybecon-
nectedinthesamefashiontotheOUTPUT1 andOUTPUT2
jacks.Audiooutputsignalissuppliedtothesejacksonly
whenfrontpanelpushbuttonSPEAKER/OUTPUT1 and2
pushbuttonsarepressedIN.Theinputimpedanceofthe
amplifiersusedshouldbe5,000ohmsorgreater.
SPEAKERCONTROLRELAY
TocontrolloudspeakersbyuseofSPEAKER/OUTPUT1
and2 pushbuttonsonthefrontpanelanaccessoryMclntosh
SCR(SPEAKERCONTROLRELAY)isneeded.Plugthespecial
cablefromtheSCRcontrolintotheSPEAKERCONTROL
RELAYreceptacle.Thespeakersarethenconnectedtothe
SCRcontrol.
TheSCRhastwoACpoweroutletsthatprovideaddi-
tionalcapacityof2400watts.Usetheseoutletstosupply
ACpowertoamplifiersorothercomponentstobecon-
trolledbytheONOFFcycleoftheC 32.UsetheSCR
wheneverthetotalloadtobeswitchedbytheC 32exceeds
itsratingof600watts.
4

TAPERECORDER3
TUNER
FMANTENNA
ACPOWERTO
TAPERECORDERS.
TUNERS,POWER
AMPLIFIERS.
TOTALOF600WATTS.
FORMOREACPOWER
USETHESCRSPEAKER
CONTROLRELAY
ACPOWER
ACPOWER
TURNTABLE#2
TURNTABLE#1
5
TAPE
RECORDER
2
TAPE
RECORDER
1

USEOF
PUSHBUTTONS
SPEAKER/OUTPUT
REMOTE
SPEAKERS
SPEAKER
CONNECTIONS
TOAC
LINE
6

MAIN
SPEAKERS
MONITORAMPLIFIER
SPEAKERS
7

UsingtheFrontPanelControls
LISTENandRECORDInputSelectorSwitches
Thecontrolatthelefttopofthefrontpanelselectsthe
inputfortheLISTENprogramline.Theleftbottomcontrol
selectstheinputfortheRECORDprogramline.Bothop-
erateinthesamemanner.
MODESELECTOR
TheMODESELECTORfacilitatestheaccurateadjustment
ofa stereosystemfordifferencescausedbyroomacous-
tics,loudspeakerplacementandtheothercomponents
usedinthesystem.
TheMODESELECTORswitchaffectstheprogramon
theLISTENprogramlineonlyandconnectstheprogram
totheloudspeakerinsevenways:
LtoL andR:Connectstheleftinputtobothloudspeakers.
RtoL andR:Connectstherightinputtobothloud-
speakers.
STEREOREV:Connectstheleftinputtotherightloud-
speakerandtherightinputtotheleftloudspeaker.
STEREO:Connectstheleftinputtotheleftloudspeaker
andtherightinputtotherightloudspeaker.
MONO(L+ R):Addstheleftandrightinputstogetherand
connectstobothloudspeakers.
L+ R toL:Connectstheleftplusrightprogramtothe
leftloudspeakeronly.
L- R toR:Connectstheleftplusrightprogramtothe
rightloudspeakeronly.
EQUALIZERFREQUENCYControls
EachoffiveEQUALIZERFREQUENCYcontrolsraisesor
lowersa bandoffrequenciescenteredonthefrequency
markedabovethecontrol.Bothleftandrightchannelsof
theLISTENprogramlineareaffected.Thecenter,orflat,
positionofthecontrolhasa detentforeasyreference.
UsetheEQUALIZERFREQUENCYcontrolstomodifythe
soundandbalanceofmaterial.Herearesomesuggestions
fromwhichtostart:
Problem
Basstooweak
Malevocalistneedsreinforcing
Femalereinforcing
Humonprogram
Violins,trumpetsdull
Drum"brushes"notaudible
EqualizerCorrection
Raise30and/or150
Raise150
Raise500
Reduce30andLFFILTER
Raise1500
Raise10K
Topreventinterferencefromsubsonicandsupersonic
signals,theC 32includessubsonicandsupersonicfilters
thatattenuatesignalsbelow20Hzandabove20,000Hz.
TheyarebypassedwhentheEQOUTpushbuttonispressed
INwhichextendsthefrequencyresponseto10Hzto
100,000Hz.
BALANCEandLOUDNESS
TheBALANCEandLOUDNESScontrolsareconcentric.
TheBALANCEcontrol(largeouterknob)adjustsforequal
volumeofeithertheleftorrightchannels.Thevolumeof
thechannelscanbevariedrelativetoeachotherwithout
affectingtheircombinedvolume.
LEFT. . . turningthecontroltotheleftaccentstheleft
channelbyreducingtherightchanneloutput.
RIGHT. . . turningthecontroltotherightaccentsthe
rightchannelbyreducingtheleftchanneloutput.
LOUDNESS
TheLOUDNESScontrol(smallcenterknob)increases
bothbassandtreblefrequenciesofbothchannelsasitis
turnedclockwise.AdjustmentoftheLOUDNESScontrol
allowslife-likefrequencybalancewhenplayingmusic
softly.Itscontouristhesame,regardlessoftheposition
ofthevolumecontrol.Thiscontourisaccuratelymodelled
afterthefamilyof"EqualLoudness"curvesidentifiedby
FletcherandMunson.
8