McIntosh C29 - User manual

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THEC 29SOLIDSTATESTEREOPREAMPLIFIER

VARIOUSREGULATORYAGENCIESREQUIRETHATWEBRINGTHEFOLLOWINGIN
FORMATIONTOYOURATTENTION.PLEASEREADITCAREFULLY.
WARNING:TOPREVENTFIREORSHOCK
HAZARD,DONOTEXPOSETHISUNITTO
RAINORMOISTURE.
TheMcintoshyouhavepurchasedisa C 29
Preamplifier.Ithasa serialnumberlocatedonthe
rearpanelofthechassis.Recordthatserialnumber
here:
Themodel,serialnumberandpurchasedateareim-
portanttoyouforanyfutureservice.Recordthepur-
chasedatehere:
Uponapplication,McintoshLaboratoryprovidesa
Three-YearServiceContract.YourMcintosh
authorizedServiceAgencycanexpediterepairs
whenyouprovidetheServiceContractwiththein-
strumentforrepair.Toassist,recordyourService
Contractnumberhere:
SerialNumber
PurchaseDate
ServiceContractNumber

YourC 29Preamplifierwill
giveyoumanyyearsofpleasantand
satisfactoryperformance.Ifyou
haveanyquestions,pleasecontact:
CUSTOMERSERVICE
McintoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903
Phone:[phone]
TakeAdvantageof3 years
ofContractService. . .
FillintheApplicationNOW.
Anapplicationfora THREEYEARSERVICECONTRACTisincludedwiththismanual.
Thetermsofthecontractare:
1.Mcintoshwillprovideallparts,
materialsandlaborneededtoreturnthe
measuredperformanceoftheinstru-
menttotheoriginalperformancelimits.
TheSERVICECONTRACTdoesnot
coveranyshippingcoststoandfrom
theauthorizedserviceagencyorthe
factory.
2.AnyMcintoshauthorizedserviceagen-
cywillrepairMcintoshinstrumentsat
normalservicerates.Toreceiveservice
underthetermsoftheSERVICECON-
TRACT,theSERVICECONTRACTCER-
TIFICATEmustbepresentedwhenthe
instrumentistakentotheserviceagen-
cy.
3.Alwayshaveservicedonebya Mcin-
toshauthorizedserviceagency.Ifthe
instrumentismodifiedordamaged,as
aresultofunauthorizedrepairtheSER-
VICECONTRACTwillbecancelled.
Damagebyimproperuseormishandl-
ingisnotcoveredbytheSERVICECON-
TRACT.
4.TheSERVICECONTRACTisissuedto
youastheoriginalpurchaser.Topro-
tectyoufrommisrepresentationthis
contractcannotbetransferredtoa se-
condowner.
5.ForyourprotectionMcintoshselects
onlydealerswhohavetechnicalcom-
petencetoguidepurchasersfairly,and
provideservicewhennecessary.To
receivetheSERVICECONTRACTyour
purchasemustbemadefroma Mcin-
toshfranchiseddealer.
6.Yourcompletelyfilledinapplicationfor
SERVICECONTRACTmustbepost-
markedwithin30daysofthedateof
purchaseoftheinstrument.
7.ToreceivetheSERVICECONTRACTall
informationontheapplicationmustbe
filledin.TheSERVICECONTRACTwill
beissuedwhenthecompletelyfilledin
applicationisreceivedatMcintosh
LaboratoryIncorporatedinBingham-
ton,NewYork.
Copyright1979© byMcintoshLaboratoryInc. 1
Contents
HOWTOINSTALL...2
HOWTOCONNECT...4
THEFRONTPANELCONTROLS
ANDHOWTOUSETHEM...8
TOPPANELCONTROLS...11
SPECIFICATIONS...12
FACILITIESANDFEATURES...13
TECHNICALDESCRIPTION...14
PERFORMANCECHARTS...15
BLOCKDIAGRAM...17
MCINTOSHTHREEYEARSERVICECONTRACT

ThePANLOCsystemofinstallingequipmentcon-
venientlyandsecurelyisa productofMcintosh
research.BydepressingthetwoPANLOCbuttons
onthefrontpanel,theinstrumentslidecanbelock-
edfirmlyinplaceoritcanbeunlockedsothatthe
chassiscanslideforward,givingyoueasyaccessto
thetopandrearpanels.
Thetrouble-freelifeofanelectronicinstrumentis
greatlyextendedbyprovidingsufficientventilation
topreventthebuildupofhighinternaltemperatures
thatcausedeterioration.Allowenoughclearanceso
thatcoolaircanenteratthebottomofthecabinet
andbeventedfromthetop.Withadequateventila-
tiontheinstrumentcanbemountedinanyposition.
Therecommendedminimumspaceforinstallation
is15inches(38.1cm)deep,17inches(43.2cm)wide,
and6 inches(15.2cm)high.
Toinstalltheinstrumentina Mcintoshcabinet,
followtheinstructionsthatareenclosedwiththe
cabinet.Foranyothertypeofinstallationfollow
theseinstructions:
1.OpenthecartonandremovethePANLOC
brackets,hardwarepackage,andmounting
templatefromthecarton.RemovetheC 29fromits
plasticbagandplaceitupsidedownontheshipping
pallet;unscrewthefourplasticfeetfromthebottom
ofthechassis.
2.Markthecabinetpanel.
Placethemountingtemplateinthepositiononthe
cabinetpanelwheretheinstrumentistobeinstall-
ed,andtapeitinplace.Thebrokenlinesthatrepre-
senttheoutlineoftherectangularcutoutalsorepre-
senttheoutsidedimensionsofthechassis.Make
suretheselinesclearshelves,partitions,orany
equipment.Withthetemplateinplace,firstmarkthe
sixA andB holesandthefoursmallholesthat
locatethecornersofthecutout.Then,jointhefour
cornermarkingswithpencillines,usingtheedgeof
thetemplateasa straightedge.
3.DrillHoles
Usea drillwitha 3/16inchbitheldperpendicularto
thepanelanddrillthesixA andB holes.Then,using
adrillbitslightlywiderthanthetipofyoursaw
blade,drilloneholeateachoftwodiagonallyop-
positecorners.Theholesshouldbarelytouchthein-
sideedgeofthepenciledoutline.Beforetakingthe
nextstep,makesurethatthesixA andB holeshave
beendrilled.
4.SawthePanelCutout
Sawcarefullyontheinsideofthepenciledlines.
Firstmakethetwolongcutsandthenthetwoshort
cuts.Aftertherectangularopeninghasbeencutout,
2

usea filetosquarethecornersandsmoothanyir-
regularitiesinthecutedges.
5.InstalltheMountingStrips
Inthehardwarepackageyouwillfindtwomounting
strips,four6-32x 1 1/4inchfillisterheadscrewsand
two4-40x 1 1/4inchinchflatheadscrews.Theseare
longenoughforanycabinetpanelthicknessupto
oneinch.
Startingattheright-handsideofthepanel,insert
a4-40x 1 1/4inchflatheadscrewintothecenter
holeinthepanel,markedB onthetemplate.Onthe
backofthepanel,aligna mountingstripwiththe
holesinthepanelandtightenthescrewuntilthe
screwheadispulledslightlyintothewood.
Repeatthisproceduretoattachthemounting
striptotheleftsideofthepanel.
6.AttachthePANLOCBrackets
Usingtwoofthe6-32x 1 1/4inchfillisterhead
screwsintheA holesoneachside,attachthe
PANLOCbracketstothecabinetpanel;theshort
flangeismountedagainstthefront(face)ofthe
cabinetpanel.Thescrewspassthroughthe
PANLOCbracketflange,thecabinetpanel,andthen
throughthemountingstripspreviouslymounted.
7.InstalltheInstrument
GuidetheACpowercordthroughthepanelopening
tothebackofthecabinet;then,slidetheinstrument
intotheopeningcarefullysothattherailsonthe
bottomofeachsideofthechassisengagethe
tracksonthemountingbrackets.Continuetoslide
theinstrumentintothecabinetuntilitisstoppedby
theadjustpositionlatches.Pressthelatchesin-
ward.Thispermitstheinstrumenttoslideintothe
cabinetuntilitsfrontpanelisflushwiththecabinet
panel.DepressthePANLOCbuttonsatthelowerleft
andrightcornersoftheinstrumentpaneltolockthe
unitfirmlyinthecabinet.DepressingthePANLOC
buttonsagainwillunlocktheinstrumentsothatit
canslideforwardtotheadjustposition.Ifyoupress
inwardontheadjustpositionlatchesyoucan
removetheinstrumentfromthecabinet.
3

HowtoConnect
Rearpanelinputjacksareprovidedfor2 stereo
highlevelsources(AUX1 andAUX2),a stereotuner
(TUNER),2 stereoturntables(PH1 andPH2),stereo
highimpedancemicrophones(MIC),and2 stereo
taperecorders(TAPE1 andTAPE2).
Rearpaneloutputjacksareprovidedtofeed2
stereotaperecorders(TAPE1 andTAPE2),a stereo
600 ohmunbalancedline(LINE)and2 stereo2.5volt
outputs(MAIN).
Frontpaneljacksprovideinputandoutput
facilitiesfora taperecorderusingthecircuitsofthe
rearpanelTAPE2 connections.Twoheadphone
jacksareprovidedwhicharefedbya stereo
amplifierintheC 29.
CONNECTINGAUX1 ANDAUX2
Connecttheleftchannelcablefromanyhighlevel
source(tuner,TVset,taperecorder,etc.)totheIN-
PUTAUX1 leftjack.Connecttherightchannelcable
totheINPUTAUX1 Rightjack.A secondhighlevel
sourcecanbeconnectedsimilarlytoINPUTAUX2.
CONNECTINGTURNTABLES
TheC 29hasshortingplugsinthephonoinputs.
Topreventunwantednoiseremovetheshorting
plugsonlyfrominputjacksthataretobeused.Con-
nectthecablefromtheleftchanneloftheturntable
intotheINPUTPHono1 leftjack.Connectthecable
fromtherightchanneloftheturntableintotheIN-
PUTPHono1 Rightjack.Fora secondturntable,
connectPHono2 inthesameway,afterremoving
theshortingplugs.
CONNECTINGMICROPHONES
Connectthecablesfromhighimpedance
microphonesdirectlyintheINPUTMICLeftand
Rightjacks.
CONNECTINGTAPERECORDERS
ToRecord:
Connecta cablefromtheOUTPUTTAPE1 Left
jacktothelefthighlevelinputofthetaperecorder.
Connecta cablefromtheOUTPUTTAPE1 Rightjack
totherighthighlevelinputofthetaperecorder.Con-
necta secondrecorderinthesamemannertothe
OUTPUTTAPE2 jacks.
ToPlayback/Monitor:
Connecta cablefromtheleftchanneloutputofa
taperecordertotheTAPEINPUT1 Leftjack.Con-
necta cablefromtherightchanneloutputofa tape
recordertotheTAPEINPUT1 Rightjack.Connecta
secondrecorderinthesamemannertotheTAPEIN-
PUT2 jacks.
FrontPanelTapeRecorderJacks:
Taperecorderinputsandoutputsareavailableat
theTAPEIN-OUTjacksonthefrontpaneljusttothe
leftoftheTAPEMONITORpushbuttons.These
jacksmakeconnectionstoTAPE2 facilitieswithout
havingtogototherearpanel.A metalshielded1/4
inchstereophoneplugisused.Connectionsaretip:
leftsignal,ring:rightsignal,andsleeve:common
ground.
4

CONNECTIONSFORTUNERS,TURNTABLES,ANDTAPERECORDERS
5
TUNER
FMANTENNA
ACPOWERTO TUNERS,TAPE
RECORDERSAND
POWERAMPLIFIERS
ACPOWER TOTURNTABLES
TAPE
RECORDER
1
TAPE
RECORDER
2
MICROPHONES
TURNTABLE2
TURNTABLE1

Whena taperecorderispluggedintothefront
jacksallthefacilitiesnormallyassociatedwith
TAPE2 ontherearpanelareautomaticallytransfer-
redtothefrontpaneljacks.
CONNECTINGTOPOWERAMPLIFIERS
Connectthejackslabeled"OUTPUTSMAIN"to
theinputofa stereopoweramplifier.TheLeftMAIN
jackisconnectedtotheleftamplifierinputjack.The
RightMAINjackisconnectedtotherightamplifier
inputjack.
CablesaresuppliedtointerconnecttheC 29to
thepoweramplifier.Longercablescanbeusedif
needed.Thelengthofthecableislimitedbytheca-
pacitanceofthecable.Thetotalcablecapacitance
mustnotexceed1,000pF.Forinstance:cableswith
acapacityof25pFperfootmaybe40feetlong.13.5
pFperfootcablemaybe75feetlong.Theinputim-
pedanceoftheamplifiersshouldbe10kohmsor
greater.
AsecondpairofMAINOUTPUTjackshavebeen
suppliedtofeeda secondpoweramplifier.Inthe
eventitisdesiredtotaperecordafterthetone,filter,
andvolumecontrolsthesecondsetofOUTPUT
MAINjackscanbeconnectedtothetaperecorder
input.Thecontrolsarethenallavailabletocontrol
thesignalbeforerecording.Remember,anychange
inthesettingofthecontrolswillchangethepro-
gramtothetaperecorder.Sincetherecordingsignal
availableattheOUTPUTMAINismuchhigherthan
theoutputavailablefromtheOUTPUTTAPE1 or
TAPE2 jacks,itwillbeeasytoover-loadthetape
recorderinput.Inthismodeofoperation,itwillnot
bepossibletomonitorfromthetaperecorderviathe
TAPEMONITORpushbuttonswhilefeedingthe
recorderfromtheOUTPUTMAINjacks.Depressing
theTAPEMONITORpushbuttonwilldisconnectthe
programsourceandmaycausefeedbackoscilla-
tion.
SPEAKERCONTROLRELAY
TocontrolloudspeakersbyuseofSPEAKERS1
and2 pushbuttonsonthefrontpanelanaccessory
McintoshSPEAKERCONTROLRELAYisneeded.
PlugthespecialcablefromtheSPEAKERCONTROL
RELAYintotheC 29backpanelSPEAKERCON-
TROLRELAYreceptacle.Inadditiontoloudspeaker
connectionsandswitching,theSPEAKERCON-
TROLRELAYhastwoACpoweroutletsthatprovide
additionalcapacityof2400watts.Usetheseoutlets
tosupplyACpowertoamplifiersorothercom-
ponentswheneverthetotalloadtobeswitchedby
theC 29exceedsitsratingof600 watts.
CONNECTINGACPOWER
ThepreamplifierACpowercordispluggedintoa
120volt60 Hz walloutlet.
TherearetwotypesofACpoweroutletsonthe
backpanel:fourblackandtwogreen.
ThegreenACpoweroutletsareonatalltimes.
PlugtheACpowercablesfromtheturntableintothe
greenTURNTABLEpoweroutletsontherearpanel.
Theblackoutletsareswitchedonandoffwhenthe
preamplifieristurnedonoroff.Theseareintended
forpoweramplifiers,equalizersandotherac-
cessoriesupto600wattstotalcapacity.
ThePOWERONpushbuttonsharesACpower
controlwiththeACpowerswitchona turntable,
througha currentdetectingswitchcircuit.Onthe
rearpaneltheTURNTABLEAUTO/MANUALswitch
selectsthemodeofoperation.Whentheswitchisin
theAUTOpositionanda turntableispluggedinto
oneofthegreenACpoweroutlets,theACpowerto
thepreamplifierandtotheblackACpoweroutlets
canbecontrolledbytheturntableon/offswitch.
WhenACpowertotheturntableisturnedon,auto-
maticallythepreamplifierandtheswitchedblack
ACpoweroutletsareturnedon.Thesystemwillre-
mainonuntiltheturntableisturnedoff.ThePOWER
ONpushbuttoncontrolstheACpowerforany
sourceotherthantheturntable.
IntheMANUALpositiononlythePOWERON
pushbuttonwillturnACpoweronoroff.
Someturntableshaveelectroniccircuitsthat
drawcurrentallthetime.Tousetheseturntablesthe
AUTO/MANUALswitchmustbeintheMANUAL
position.WiththeAUTO/MANUALswitchinthe
MANUALposition,ACpowertothesystemwillbe
controlledbythefrontpanelPOWERpushbuttononly.
ThegreenACpoweroutletsareprotectedwitha
oneamperefuse.Anyincreaseinthevalueofthis
fusewillaffecttheprotectionofthesensingcircuit
andcancausedamage.
CONNECTINGPROGRAMSOURCEGROUNDS
AsingleGROUNDpostisprovidedtowhich
groundsforturntables,recordchangers,tapedecks,
etc.areconnected.Topreventhumpickup,theleft
andrightprogramcablesandthegroundwirefrom
thatsourceshouldbewoundortwistedtogether.
Makesurethegroundwiredoesnotmakeanycon-
nectiontotheshieldsoftheleftandrightprogram
cablesbetweenthesourceandtheinputofthe
preamplifier.
FUSES
A1.0AMPfuseprotectsthepreamplifiercircuits.
Thefusedoesnotprotectadditionalequipmentcon-
nectedtothebackpanelACoutlets.
ThegreenACpoweroutletsareprotectedwitha
oneamperefuse.Anyincreaseinthevalueofthis
fusewillaffecttheprotectionofthesensingcircuit
andcancausedamage.
6

OPTIONALSCR2 FOR
PUSHBUTTONSWITCHING
OFMAINANDREMOTE
SPEAKERS.
SECONDARY
SYSTEM
SPEAKERS
CONNECTIONSFORPOWERAMPLIFIERSANDLOUDSPEAKERS
7
POWERAMPLIFIER
MAINSPEAKERS
REMOTE
SPEAKERS
POWER
AMPLIFIER

TheFrontPanelControlsand
HowtoUseThem
BALANCEand
LOUDness
TheBALANCEand
LOUDnesscontrolsare
concentric.TheBAL-
ANCEcontrol(large
outerknob)adjustsfor
equalvolumeofeither
theleftorrightchan-
nels.Thevolumeofthechannelscanbevaried
relativetoeach.
left. . . turningthecontroltotheleftaccentsthe
leftchannelbyreducingtherightchanneloutput.
right. . . turningthecontroltotherightaccents
therightchannelbyreducingtheleftchannelout-
put.
LOUDness
UsetheLOUDnesscontrolforfullfrequency
rangelisteningateventhesoftestlisteninglevels.
TheLOUDnesscontrol(thesmallcenterknobofthe
concentriccontrol)provideslow-frequencyboostto
compensatefora hearingcharacteristicofthe
humanearatlowlisteninglevels.Theearbecomes
lesssensitivetolowfrequenciesasvolumeisreduc-
ed.Increasedloudnesscompensationistherefore
desirableatlowerlisteninglevels.Theloudness
controlbooststhelowfrequenciessothattheear
hearsapproximatelythesamemusicalbalanceasit
wouldathigherlisteninglevels.
FLAT:(Maximumcounterclockwiserotation)Full
volumewithflatfrequencyresponse.Theloudness
compensationisinoperativeinthisposition.
TurningthecontrolclockwisetowardMAX
reducesthelisteningvolume,andautomaticallyin-
creasesthecompensationbyboostingbass.
INPUTSELECTOR
ThesixpositionINPUTSELECTORcontrolsthein-
putprogram.WhentheINPUTSELECTORisturned
to:
AUX1:theoutputfromanyhighlevelprogram
sourcerequiringflatamplificationisconnectedto
thehighlevelinputstage.Sucha sourcecouldbe
anothertaperecorder,ora televisionset.
AUX2:sameasAUX1
TUNER:theoutputfromanyAM,FMorMPXFM
tunerisconnectedtothehighlevelinputstage.In
theTUNERpositiontheC 29hasflatamplification.
8

PHono1:theoutputofa magneticphonocar-
tridgepluggedintoPHono1 isconnectedtothelow
levelamplifyingstages.Theresponseofthese
stageshasbeenshapedtopreciselyconformto
revisedRIAAstandards.
PHono2:SameasPHono1
MIC:theoutputofanyhighimpedance
microphoneisconnectedtothelowlevelinput
stage.IntheMICpositiontheC 29hasflat
amplification.
MODESELECTOR
TheMODESELECTORfacilitatestheaccuratead-
justmentofa stereosystemforsomedifferences
causedbyroomacoustics,loudspeakerplacement
andtheothercomponentsusedinthesystem.
TheMODESELECTORswitchconnectsthepro-
gramtotheloudspeakerinsevenways:
LtoL andR:Connectstheleftprogramtoboth
loudspeakers.
loudspeakerandtherightprogramtotheright
loudspeaker.
MONO(L+ R):Addstheleftandrightprograms
togetherandconnectstobothloudspeakers.
L+ R toL:Connectstheleftplusrightprogramto
theleftloudspeakeronly.
L+ R toR:Connectstheleftplusrightprogramto
therightloudspeakeronly.
VOLUMECONTROL
TheVOLUMEcontrol
isa precisionstepcon-
trolmanufacturedfor
McintoshLaboratory.It
has32stepswitha 70
dBrange,plusvolume
off.Leftandrightchan-
neltrackingarewithin
1dB.Thisextremeaccuracyisobtainedthrough
specialelectronicallycontrolledresistanceelement
trimming.
RtoL andR:Connectstherightprogramtoboth
loudspeakers.
STEREOREV:Connectstheleftprogramtothe
rightloudspeakerandtherightprogramtotheleft
loudspeaker.
STEREO:Connectstheleftprogramtotheleft
BASS
Concentric,11posi-
tion,tonecontrolswit-
chesadjustthebass.
Theouterknobadjusts
therightchannelbass
response.Theinner
knobadjuststheleft
channelbassresponse.
Left:Adjuststhebassloudnessfromtheleftloud-
speaker.Clockwiserotationincreasesthebass
loudnesswhilecounterclockwiserotation
decreasesthebassloudness.Eachstepofthetone
controladjuststhebassloudnessabout4 dB.
Right:Hasthesameeffectonthesoundfromthe
rightloudspeaker.
TREBLE
Concentric,11position,tonecontrolswitchesad-
justthetreble.Theouterknobadjuststheright
9

channeltreblere-
sponse.Theinnerknob
adjuststheleftchannel
trebleresponse.
Left:Adjuststhetre-
bleloudnessfromthe
leftloudspeaker.Clock-
wiserotationincreases
thetrebleloudness
whilecounterclockwiserotationdecreasesthetre-
bleloudness.Eachstepofthetonecontroladjusts
thetrebleloudnessabout4 dB.
Right:Hasthesameeffectonthesoundfromthe
rightloudspeaker.
TAPEPUSHBUTTONS
IMPORTANT:WhentheC 29isoperatedwitheither
MONITORpushbuttonattheinposition,thepro-
gramheardwillbethatfromthetaperecordersonly.
Signalfromanyothersourcewillnotbeheardfrom
theloudspeakers.Tohearanyothersource,make
suretheMONITORpushbuttonsareOUT.
TheMONITORswitchesaremechanicallyin-
terlockedtopreventsimultaneousmonitoringfrom
twotaperecorders.Ifonebuttonisattheinposi-
tion,itmust bepushedagaintoreleaseittotheout
positionbeforetheotherbuttoncanbepushed.
TheC 29isdesignedsoitmaybeusedwithtwotape
recorders.Thefourleftpushbuttonscontrolthe
signaloutputoftheserecorders.Theypermitrecor-
dingstobemonitoredastheyarebeingrecorded,or
copyingoftapesfromonerecordertoanotherwhile
listeningtoa separateprogramortheplaybackof
eitherrecorder.
MONITORTAPE1 pushbuttonout:Theprogram
sourceasselectedbytheINPUTSELECTORisfed
tothepoweramplifiersandheardthroughthe
loudspeakers;pushbuttonin:Signalfroma tape
recorderpluggedintoINPUTSTAPE1 isfedtothe
poweramplifiersandheardthroughthe
loudspeakers.
MONITORTAPE2 pushbutton:Functionssimilarly
tomonitorTape1.Italsocontrolstheprogramfrom
ataperecorderpluggedintothefrontpanelTAPEIN
andOUTjacks.Whena taperecorderispluggedinto
thefrontjacksallthefacilitiesnormallyfedtoTAPE
2ontherearpanelareautomaticallytransferredto
thefrontpanel.Thetaperecorderpluggedintothe
TAPE2 INandOUTjacksontherearpanelis
automaticallydisconnected.
TAPECOPYT1T2pushbuttonin:connectsthe
outputfromtaperecorder1 totheinputoftape
recorder2 withoutaffectingtheprogrambeing
heardfromthespeakers.Inthispositiona copyof
theprogramontaperecorder1 canbemadeontape
recorder2.TomonitortheoriginaluseMONITOR
TAPE1 pushbuttonandtomonitorthecopyuse
MONITORTAPE2 pushbutton.
TAPECOPYT2T1pushbuttonin:connectsthe
outputfromtaperecorder2 totheinputoftape
recorder1 withoutaffectingtheprogrambeing
heardfromthespeakers.InthispositionA copyof
tapeprogramonrecorder2 canbemadeonrecorder
1.TomonitortheoriginaluseMONITORTAPE2
pushbuttonandtomonitorthecopyuseMONITOR
TAPE1 pushbutton.
LF-HFFILTERS
UsetheLF-HFFILTERSpushbuttontoreduceob-
jectionablelowandhighfrequencynoises(below50
Hzandabove7 kHz).Withthepushbuttonin,noise
isreduced;out:filtersaredisconnected.
SPEAKER1 and2
Speakerscanbeturnedonandoffwhenproperly
connectedwiththeaccessoryMcintoshSPEAKER
CONTROLRELAY.TheSPEAKER1 and2 pushbut-
tonscontroltheoperationofa SPEAKERCONTROL
RELAYwhenitispluggedintotheC 29rear
SPEAKERCONTROLRELAYsocket.
TheSPEAKERCONTROLRELAYcontrolsthe
audiototwopairsofstereoloudspeakers.TheAC
powertotwoACreceptaclesontheSPEAKERCON-
TROLRELAYiscontrolledbytheON-OFFcycleof
theC 29.ThetotalcapacityoftheSPEAKERCON-
TROLRELAYACpowerreceptaclesis2400watts.
POWERON
ThePOWERONpushbuttonsharesACpower
control,througha currentdetectingswitchcircuit,
withtheACpowerswitchona turntable.Ontherear
paneltheTURNTABLEAUTO/MANUALswitch
selectsthemodeofoperation.
WhentheswitchisintheAUTOpositionanda
turntableispluggedintooneofthegreenACpower
outlets,theACpowertothepreampandtotheblack
ACpoweroutletscanbecontrolledbytheturntable
on/offswitch.WhenACpowertotheturntableis
turnedon,automaticallythepreamplifierandthe
SWITCHEDblackACpoweroutletsareturnedon.
Thesystemwillremainonuntiltheturntableisturn-
edoff.ThePOWERONpushbuttonswitchparallels
theautomaticturntablepowercontrolfeature.The
POWERONpushbuttonisusedtoturnonandoff
powerwhentheturntableisnotused.ThePOWER
ONpushbuttonmustbeoutorofffortheturntable
tocontroltheACpower.
IntheMANUALpositiononlythePOWERON
pushbuttonwillturnthepreamplifierandblack
outletACpoweronandoff.
TAPERECORDERFRONTPANELCONNECTION
Inputandoutputfacilitiesareavailableatthe
TAPEIN-OUTjacksonthefrontpanel.Thesefront
10

paneljacksmakeconnectionswithouthavingtoget
attherearpanel.Whenusingthefrontpaneljacks,
therearpanelTAPE2 facilitiesaredisconnected
automatically.A metalshielded1/4inchstereo
phonoplugisusedforbestshielding.Connections
followtheindustrystandardsandaretip:leftsignal,
ring:rightsignal,and,sleeve:commonground.
HEADPHONES
ThefrontpanelHEADPHONEjackhasbeen
designedtofeedlowimpedancedynamichead-
phones.Electrostaticheadphonesgenerallyrequire
higherpowerthandynamicheadphonesandare
connectedtotheoutputterminalsonthepower
amplifier.
PlugheadphonesintothefrontpanelHEAD-
PHONEjack.AdjustthefrontpanelVOLUMEcontrol
forcomfortableheadphonelistening.Additionaltop
panelHEADPHONELEVELcontrolsalsoadjustthe
loudnessoftheprogramwhenusingheadphones.
Seethesectionbelowfortoppanelcontrols.
AnamplifierintheC 29providesthepowerthat
feedsboththeHEADPHONEjacksonthefront
panelandtheLINEOUTPUTjacksontherearpanel.
TopPanelControls
Togainaccesstothetoppanelcontrolsdepress
thePANLOCbuttonsandpullthepreamplifieroutto
theadjustposition.Thecontrolsarenoweasily
operated.
HEADPHONE& LINEOUTPUT
Acontrolhasbeenprovidedineachchanneltoad-
justtheloudnessoftheprogramwhenusinghead-
phones.Thecontrolsadjusttheoutputineachchan-
neltotheHEADPHONEjackonlyanddonotaffect
theprogramloudnessfromtheloudspeakers.Toad-
justforcomfortableheadphonelisteningfirstadjust
theVOLUMEcontroltonormalroomloudness.
Then,whilewearingtheheadphones,adjustthe
HEADPHONELEVELcontrolstothedesiredloud-
nesslevel.
MAINOUTPUTLEVEL
Acontrolhasbeenprovidedineachchannelthat
adjuststheoutputofthepreamplifier.Usethese
controlstocompensateforminordifferencesin
roomeffects,loudspeakerefficiencyoramplifier
gain.
PANLOC
McintoshdevelopedPANLOCmountingbrings
professionalinstallationtechniquetostereo.
DepressingthePANLOCbuttonwillreleasethein-
strument.Itcanthenbepulledtowardyoutothe
"adjustment"position.Inthispositionthetoppanel
controlscanbeadjusted.
Beststereoperformanceisachievedwhenthe
stereosystemisproperlybalanced.Forproper
balanceeachchannelmustbeequalinloudness.
Usethetoppanellevelcontrolstobalancesystem
loudness.
ThisprocedurereservestheBALANCEcontrolto
adjustforanyunbalanceinthesourcematerial,the
record,etc.
Beforeattemptingtobalancethesystemmake
certainthefrontpanelcontrolsaresetproperly.
SettheMODESELECTORtoMONOandthe
BALANCEcontrolatthecenteror12o'clockposi-
tion.Turnthetonecontrolstothecenteror12
o'clockposition.TheHF- LFpushbuttonsshouldbe
intheOUTposition.
Withthetunerturnedon,turnuptheVOLUME
controlonthefrontpaneluntila comfortableroom
loudnessisreached.AdjustthetoppanelMAIN
OUTPUTLEVELcontrolsuntiltheloudnessfrom
eachloudspeakerisequal.
11

PERFORMANCELIMITSANDRATINGS
WepromiseyouthattheC 29youbuy,atthetime
ofyourpurchase,iscapableofperformanceatorex-
ceedingtheselimitsoryougetyourmoneyback.
McintoshPERFORMANCELIMITSarethemaximum
departurefromperformanceperfectionpermitted
fora Mcintoshinstrument.
FREQUENCYRESPONSE
+0 -0.5dB20Hzto20,000Hz
DISTORTION
.02%maximumatratedoutputlevel,20Hzto20,000
Hz
INPUTSENSITIVITYANDIMPEDANCE
Auxiliary,TUNER,TAPE1,TAPE2,0.25voltsat
100,000ohms;PHono1 andPHono2,2 millivolts
(1,000Hz)at47,000ohmsand65pF;MICrophone,2.5
millivoltsat10,000ohms
HUMANDNOISE
Auxiliary,TUNER,TAPE1,TAPE2,IHFA100dB,
unweighted90dBbelowratedoutput;PHono1,
PHono2 IHFA90dB,unweighted80dBbelow10
millivoltsinput,equivalenttolessthan1.0microvolt
attheinputterminals;MICrophone,1.5microvoltsat
theinputterminals.
OUTPUTLEVELANDIMPEDANCE
MAIN:2.5voltswithratedinput,lessthan100ohms
sourceimpedance,tooperateinto10,000ohmsor
greater
TAPE:0.25voltswithratedinput,lessthan200 ohms
sourceimpedance,tooperateinto10,000ohmsor
greater
HEADPHONE/LINE:0.75voltsinto8 ohmloador2.5
voltsinto600 ohmline,47ohmsourceimpedance,
levelcontrolsprovided
VOLTAGEAMPLIFICATIONINDECIBELS
Auxiliary,TUNER,TAPE1 andTAPE2
toMAINOutput20dB
toTAPEOutput0 dB
toHEADPHONE/LINEOutput30dB
PHono1 andPHono2 at1 kHz
toMAINOutput62dB
toTAPEOutput42dB
toHEADPHONE/LINEOutput72dB
MICrophone
toMAINOutput60dB
toTAPEOutput40dB
toHEADPHONE/LINEOutput70dB
SEMICONDUCTORCOMPLEMENT
9IntegratedCircuits
2Transistors
11SiliconDiodes
8LightEmittingDiodes(LED)
1SiliconControlledRectifier(SCR)
1DualLightDependentResistorNetwork(LDR)
POWERREQUIREMENT
120volts,50/60Hz,45watts
SIZE:FrontPanelmeasures16incheswide(40.6cm)
by5 7/16incheshigh(13.8cm).Chassismeasures14
3/4incheswide(37.5cm)by4 13/16incheshigh(12.2
cm)by13inchesdeep(30.0cm),includingPANLOC
shelfandbackpanelconnectors.Knobclearancere-
quiredis1 1/4inches(3.2cm)infrontofthemoun-
tingpanel.
FINISH:Frontpanelisanodizedgoldandblackwith
specialgold/tealnomenclatureillumination.
Chassisisblack.
MOUNTING:ExclusiveMcintoshdevelopedprofes-
sionalPANLOC
WEIGHT:19pounds(8.6kg)net,31pounds(14.1kg)
inshippingcarton
12
Specifications

FacilitiesandFeatures
BASSCONTROLS
Separate11positionrotaryswitchesforeach
channel,+20dBto-20dBat20Hz
TREBLECONTROLS
Separate11positionrotaryswitchesforeach
channel,+ 18dBto- 18dBat20,000Hz
BALANCECONTROL
Naturalbalanceatcenterposition,attenuationof
leftorrightchannelbyrotatingcontrol
PRECISETRACKINGVOLUMECONTROL
Aprecisionstepvolumecontrolwithlefttoright
trackingaccuracywithin1 dBthroughitsentire
range.
SIXSOURCEINPUTSELECTOR
Auxiliary1 and2,TUNER,PHono1 and2,
Microphone
MODESELECTOR
Sevenpositions:Leftchannelonlytoboth
speakers,Rightchannelonlytobothspeakers,
StereoReverse,Stereo,Mono,L + R toleftspeaker
only,andL + R torightspeakeronly
TAPEMONITORSWITCHES
Twopushbuttonswitches.Eitheroftwotape
recorderscanbemonitoredbyselectingtheTAPE1
pushbuttonorTAPE2 pushbutton.Theyare
mechanicallyinterlockedtoacceptonlyone
pushbuttonattheINpositionatonetime.
TAPECOPYSWITCH
Twopushbuttonswitches.Eitheroftwotape
recorderscanbeconnectedtocopyfromtape
recorder1 totaperecorder2 orviceversa.Theyare
mechanicallyinterlockedtoacceptonlyone
pushbuttonattheINpositionatonetime.
LF- HFFILTERS
Reduceunwantedhighfrequencynoise(above7
kHz)andlowfrequencyrumbleetc.(below50Hz)at
12dBperoctaverate.
FRONTPANELTAPEJACKS
Allowsconnectiontoinputandoutputofa tape
recorderfromthefrontpanel.Insertingplugsinto
thefrontpaneljacksdisconnectstheTAPE2 cir-
cuitsfromtherearpanelandusestheTAPE2
facilitiesforthefrontpaneljacks.
HEADPHONEJACKS
Forlisteningwitheitherloworhighimpedance
dynamicstereoheadphones.Powertothesejacksis
suppliedbyanamplifierintheC 29.Headphone
listeningcanbeaccomplishedwithouttheuseofan
externalpoweramplifier.
SPEAKERSWITCHES
(Operateswithaccessoryspeakercontrolrelay)
Turntwosetsofspeakersonoroffwhenproperlyin-
terconnectedwiththeaccessorySPEAKERCON-
TROLRELAY.
MAINOUTPUTLEVELCONTROLS
Permitsthebalanceoftheentiresystemtobe
convenientlypreset.
HEADPHONE& LINEOUTPUTLEVELCONTROLS
AdjuststhelevelandbalanceoftheHEAD-
PHONE/LINEoutput.
13

TechnicalDescription
AUDIOSECTION
EachchanneloftheC 29hasfourbasicsections.
Theyare:phonoamplifier,highlevelamplifier,filter
amplifier,andheadphoneamplifier.
PHONOAMPLIFIER
Thephonoamplifierusesa hightechnologyin-
tegratedcircuitoperationalamplifier.Itsdifferential
inputstagehasbeenoptimizedforlownoiseand
lowdistortionperformance.Openloopgainofthis
integratedcircuitis100,000.Withhighopenloop
gaina largeamountofnegativefeedbackcanbeus-
edaroundthephonoamplifiertofurtherreduce
noiseanddistortion.Thefeedbacknetworkalsopro-
videsprecisionRIAA frequencycompensation.The
networkuses1%metalfilmresistorsand5%poly
filmcapacitors.Toachievelownoiseperformanceit
isessentialthatthefeedbacknetworkbeverylow
impedance.Asa consequence,thepreamplifier
mustbecapableofoperatingasa poweramplifierto
drivethisimpedance.Theactualpoweroutput
capabilityofthispreamplifierstageismorethan100
milliwatts,a greatmarginbeyondthatwhichisre-
quired.
Inputsensitivityofthephonoamplifieris2
millivolts.Thegainoftheamplifieris42dBat1000
Hz.Thephonoamplifierhasa verywidedynamic
range.At1000Hzthephonoinputcircuitwillaccept
100millivoltswithoutoverload,a voltagefargreater
thantheoutputofanycurrentmagneticphonocar-
tridge.Phonoinputoverloadthereforeisvirtuallyim-
possible.A signallevelof10millivoltsatthephono
inputat1000Hzwillproduce1.2voltsatthetape
output.Thetapeoutputhasa sourceimpedanceof
200ohms,designedtooperateintoa loadim-
pedanceof47,000ohmsorgreater.
HIGHLEVELAMPLIFIER
Attheinputtothehighlevelamplifierthesignal
passesthroughthemodeswitch,thenthroughthe
volumecontrolandtheloudnesscontrol.The
loudnesscontrolisindependentofthevolumecon-
trolpermittinganyamountofloudnesscompensa-
tiontobeintroducedregardlessofthepositionof
thevolumecontrol.Thelinearhighlevelamplifier
hasa gainof20dB.Thesametypeintegratedcircuit
operationalamplifierasusedinthephonoamplifier
isusedtominimizenoiseanddistortioninthehigh
levelamplifier.Thefeedbacklooparoundthis
amplifierusesfrequencyselectivebassandtreble
networkswithtwo11positionswitcheswhichallow
upto20dBofboostorcutat20Hzandupto18dB
ofboostorcutat20,000Hz.
FILTERAMPLIFIER
Thefilteramplfierservesthreefunctions:a high
frequencyfilter,a lowfrequencyfilteranda 20,000
Hzlowpassfilter.Eachchannelofthefilter
amplifieragainutilizesthesametypeoperational
amplifieraswasusedinthephonostageandhigh
levelamplifier.Theresistiveandcapacitive
elementsforma 12dBperoctaveactiveRCfilter.
Thehighfrequencyfilterisa 7,000Hzactivelow
passfilter.Thelowfrequencyfilterisa 50Hzactive
highpassfilter.Thefilteramplifieralsoformsa
20,000Hzactivelowpassfiltertoreducenoiseout-
sidetheusefulsoundspectrumwhileleavingthe
preamplifierresponseflatto20,000Hz.Thislow
passfilterisconnectedatalltimestoreducewide
bandnoiseyetmaintainingflatfrequencyresponse
to20,000Hz.Thenon-lineardistortionoftheactive
filterelementsintheC 29isverylowevenatcutoff
frequency.Thisisnotalwaysthecasewithpassive
filtersthatpresenttothedrivingsourcea verylow
impedanceatcutofffrequency.
HEADPHONEAMPLIFIER
Theintegratedcircuitheadphoneamplifieris
capableofdrivingtwopairsofdynamicheadphones
withlessthan.1%harmonicdistortion.Themax-
imumoutputoftheheadphoneamplifieris2.5volts
into50ohmsorgreater.Internalimpedanceofthe
headphoneamplifieris47ohms.Longshielded
cablescanbeusedwithoutadverselyaffectingthe
frequencyresponse.Theheadphonelevelcontrols
adjusttheoutputlevelandbalanceofthehead-
phoneamplifier.
TURNONDELAY
TheC 29hastransientfreeturnonandturnoff
characteristics.A lightdependentresistor,timecon-
trolled,connectstheoutputofthepreamplifierto
theoutputjacks.Thecontroltotheresistorisderiv-
edfroma longtimeconstantthatturnsonapprox-
imatelytwosecondsafterthepowerswitch.The
samecircuithasa shortturnofftimeconstant
whichturnsoffbeforethepreamplifier'smainpower
supplyhasa chancetodischarge.
AUTOTURNON
OntherearpanelaretwogreenACpoweroutlets
andanAUTO/MANUALslideswitch.PlugtheAC
powercablesfromtheturntableintothegreenturn-
tablepoweroutletsontherearpanel.Whenthe
switchisintheAUTOpositioncurrentthatisdrawn
bytheturntablewillbesensedandwillcausea relay
toclose.ThisrelaycontrolstheACpowertotheC 29
andtheblackACpoweroutlets.Whenthecurrent
drainceasesthepreamplifierandtheACpower
outletswillturnoff.Thecompletesystemcanbe
controlledfromtheturntableoffandonswitch.
14

FREQUENCYINHERTZ
15
PerformanceCharts
FREQUENCYINHERTZ
BASSANDTREBLECONTROLCHARACTERISTICS
FREQUENCYINHERTZ
PHONOEQUALIZATION(RIAA)ANDMICROPHONERESPONSE
LOWANDHIGHFREQUENCYFILTERCHARACTERISTICS
FREQUENCYINHERTZ
LOUDNESSCONTROLCHARACTERISTICS
HARMONICDISTORTIONATRATED OUTPUT
FREQUENCYINHERTZ

ThefrontpanelPOWERONpushbuttonmustbe
leftintheofforoutpositionforthisautomaticcon-
troltooperate.Whentherearpanelslideswitchisin
themanualposition,onlythefrontpanelpushbutton
hascontrol.
POWERSUPPLY
Tominimizehumpickupandthusimprovesignal
tonoiseratiotheC 29powertransformeristriple
shielded.Shieldingincludesa copperstrap,a
siliconsteelstrap,anda steeloutershell.The
transformeroutputvoltageisfedtoa fullwave
bridgerectifierwith3,000microfaradfilter
capacitorstoprovidethe+ 24voltsforpoweringthe
headphoneamplifierandtheplusvoltageregulator
and-24voltsfortheminusregulator.The±18
voltsneededforlowlevelandoperationalamplifier
stagesiscontrolledwithintegratedcircuitvoltage
regulators.
16

MCINTOSHLABORATORYINC.
2CHAMBERSST.,BINGHAMTON,N.Y.13903
039116
607-723-3512
Thecontinuousimprovementofitsproductsisthepolicyof
McintoshLaboratoryIncorporatedwhoreservetherightto
improvedesignwithoutnotice.
PrintedinU.S.A.