McIntosh C4 - User manual

INSTRUCTIO NMANUA L
MclNTOS HMODE LC- 4an dC-4 P
AUDI OCOMPENSATOR S
SerialNo.6600andabove
MclNTOSHLABORATORY,INC.
2ChambersSt.Binghamton,N.Y.
U.S.A.
5M-357-HPB

— 1—
INSTRUCTIONMANUAL
MclNTOSHMODELC-4andC-4P
AUDIOCOMPENSATORS
TheMcintoshAudioCompensatorisa completecontrolunitforprofessionalorhomeentertain-
mentsystems.TheAudioCompensatorsuppliesthenecessarygainandequalizationforusewithlowlevel
phonographcartridgesaswellasthehighoutputofradiotuners.
PowerSource
Output
InputSensitivityandImpedance
FrequencyResponse
HarmonicDistortion
HumandNoiseLevel
Size
Weight
ELECTRICALANDMECHANICALSPECIFICATIONS
C-4:AnyMcintoshpoweramplifier
C-4P:Self-Powered
Main:2.5voltswithratedinput
Tape:0.5voltswithratedinput
TapeandTuner:0.5V.,500K.Mic:5MV,100K
Phono1:5MV,100K
Phono2:5MV,variable6.8K-52K
SeeGraphs
Lessthan0.3%at2.5voltsoutput,20-20,000cycles
TapeandTuner:Betterthan80dbbelowoutput
MicandPhono:Lessthan2 microvoltsatinputterminals
(—115dbm)
C-4andC-4P:101/8"x 39/16"x 7½"
FrontPanel:11"x 4¼"(Knobsproject¾")
D8A:6"x47/8"x2¼"(PowersupplysectionofC-8P)
C-4:8 lbs. C-4P:11lbs.,6oz.
FRONTPANELCONTROLS
INPUTS
CONTROLAFFECTED
SelectorAll
VolumeAll
BassandTrebleToneAll
CompensationSwitchPhono
PURPOSE
Selectdesiredsoundsource.
Controlsoundlevel.
Continuouslyvariablecontroloflowandhighfrequencies.
Providefrequencycompensationforphonographrecordingsor
tapeheads.

—2 —
INSTALLATIONOFMODELC-4andC-4P
AUDIOCOMPENSATORS
TheC-4orC-4Pmaybeusedinitsowncabinetormaybeeasilymountedinanyequipmentcabinet
byusingthemountingtemplatessuppliedwiththismanual.
Aftertheseunitshavebeensecuredintheirdesiredlocation,proceedasfollows:
1.Connectspeakertooutputofpoweramplifier.
2.InsertpoweramplifierlinecordintooneoftheAuxiliaryA.C.receptaclesprovidedattherearchassis
oftheAudioCompensator.
3.C-4:Connectinter-unitcabletosocketlabeled"PRE-AMP.INPUT"onMcintoshpoweramplifiers.
AdjustgaincontrolfullycounterclockwisewithMC-30orMC-60.CAUTION:THEINTER-UNITCABLE
MUSTNOTBEREMOVEDFROMTHEC-4.
C-4P:InsertcableofD-8ApowersupplyintotheoctalsocketontheC-4P.Connectaudiocablepro-
videdbetweenRETMApinjacklabeled"MAINOUTPUT"onC-4Pand2.5Vinputofpoweramplifier.
(Socketlabeled"PRE-AMPINPUT"onMcintoshpoweramplifiers.Adjustgaincontrolfullycounterclock-
wisewithMC-30orMC-60.)
4.TheAudioCompensatoroutputis2.5voltswithratedinputsignalandthepoweramplifiershouldbe
adjustedforthisinputsensitivity.However,anyamplifierrequiringlessthan2.5voltsinputmaybeusedsince
thevolumecontrolontheAudioCompensatorislocatedattheoutput.Reducingthiscontrolwillnotincrease
eitherthedistortionornoiselevel.
5.TurnthevolumecontrolontheAudioCompensatorto"OFF."
6.InsertpowercordoftheAudioCompensatorintoa 117V.A.C.poweroutlet.
7.TurnthevolumecontrolontheAudioCompensatorclockwiseuntilthepowerswitchisactivated.
Allowthirtysecondsforwarm-up,thenadvancethevolumecontrolto"10."
8.C-4:Adjustthehumreducingpotentiometeronthepoweramplifierforminimumhum.
C-4P:Adjustthehumreducingpotentiometeronthepowersupplyforminimumhum.
Thisadjustmentwilloccuratoneendofrotation.TheC-4andC-4Phavea D.C.supplyforthe
tubeheatersandminimumhumwillbeachievedwhenthecorrectsideofthissupplyisgrounded.
9.TurnthevolumecontrolontheAudioCompensatortooff.
10.InsertinputsintheirproperjacksatthebackoftheAudioCompensator,andallA.C.powercords
intotheA.C.outletsprovided.
INPUTCONNECTINGPROCEDURE
TheinherenthumandnoisevoltagesappliedtotheinputoftheAudioCompensatorare—115DBM,
orlessthan2 microvolts.ToavoidloweringthesignaltohumratiooftheAudioCompensator,byadding
humvoltagestotheinput,extremecaremustbetakeninitsinstallation.Weofferthefollowingrecommenda-
tionsasa guidetoinstallation:
1.ConnectinputsofAudioCompensatorasoutlinedonthetablebelow:
INPUT(FORINPUT
CHANNEL2.5VOUTPUT)GAINIMPEDANCEUSE
TAPEAND
TUNER0.5V15db500K
MIC5MV53db100K
PHONO1 5MV53db100K
Variable
PHONO2 5MV53db6.8K-52K
RadioorTVTuners.Taperecorderswithself-containedequal-
izers.
Lowimpedancemicrophoneinconjunctionwithaninputtrans-
formersuchasMcintoshM-107.
Magneticphonographcartridges.Taperecorderwithoutself-
containedequalizers(tapeheads).
Magneticorconstantamplitudephonographcartridges.
Tapeheads.

-3-
2.TheAudioCompensatorandmagneticphonographcartridgesshouldbemountedatleasttwofeet
frompowertransformers.
3.Inter-unitcablesprovidea completegroundsystem.Alternategroundwirescreategroundloopswhich
willusuallyincreasehumlevel.
4.The12AX7tubesusedintheAudioCompensatorareheatedwithD.C.Thehumadjustcontrolon
thepowersourcefortheseunitsrequiresaninitialadjustmenttocorrectlybalancetheD.C.supply.Correct
adjustmentwilloccuratoneendofrotationandwillbeevidentbytheabsenceofhum.
5.GroundingtheturntablemotorframetotheAudioCompensatorchassisneartheinputjacksmayre-
ducethehumlevelonthephonographchannels.Donotusetheshieldonleadfromcartridgeforthisconnec-
tion.
AllchannelsoftheAudioCompensatorhaveaninputlevelcontrolwhichshouldbeusedtoreducesignal
inputinexcessoftheirratedvalue(seespecifications).Properadjustmentofthesecontrolswillallowswitch-
ingchannelswithouta changeinvolume.
Iftheinputsignalvoltageisunknownthelevelcontrolsmaybeadjustedasfollows:
1.Turnthelevelcontroloff(fullycounterclockwise).
2.Setthemainvolumecontrolat"7."
3.Adjustthegaincontrolfora reasonablyloudlisteninglevel.
4.Ifa highlyefficientspeakersystemisused,theleveladjustmentshouldbemadewiththevolumecon-
trolat"5."
TapeandTunerChannels:
Thesechannelseachhaveaninputimpedanceof500,000ohmsandsensitivityof0.5volts.Theflatfre-
quencyresponseofthesechannelsmaybemodifiedbytheTonecontrolsasdesired.
MicChannel:
Thischannelhasaninputimpedanceof100,000ohmsandsensitivityof5MV.Itisintendedtobeused
witha lowimpedancemicrophoneinconjunctionwitha suitableinputtransformer.Theflatfrequencyresponse
ofthischannelmaybemodifiedbytheTonecontrolsasdesired.
Phono1 Channel:
Thischannelhasaninputimpedanceof100,000ohmsandsensitivityof5MV.Itisfrequencycompen-
satedforusewithmagneticphonographcartridgesortapeheads.Thishighinputimpedanceissuitablefor
operationwiththeAudaxphonographcartridge,ortheinputimpedancemaybeloweredbyconnectinga re-
sistoracrosstheinputofthefollowingvalues:
DesiredImpedanceResistorAcrossInput
100KNone
50K(47K)100K
27K36K
12K15K
Phono2 Channel:
ThischannelisthesameasPhono1,exceptthata variableloadcontrolhasbeenprovidedwhichvaries
theinputimpedancefrom6.8Kto52K.Thiscontrolincorporatesa switchwhichisactivatedintheextreme
counterclockwiseposition.Inthispositiontheinputisterminatedforusewithconstantamplitudecartridges.
Thefollowingtablelistsrecommendedterminationforseveralcartridges:
ThesignalfromtapeheadsmaybeconnecteddirectlytooneofthephonochannelsandtheAudioCom-
pensatorusedforequalizationoftherecordedtape.TheCompensationswitchshouldbesetatposition"800,
10"fortapeequalization,andthetonecontrolsmaybeusedtovarythefrequencyresponseasdesired.
CARTRIDGE
Pickering(200Series)
PickeringFluxvalve
G.E.variablereluctance
Fairchild(inputtransformer not necessary)
ADJUST
LOADCONTROL
27K
47K
47K
47K
CARTRIDGE
E.S.L.withinputtransformer
FMtypecartridges—crystalorceramic
Audax—UsePhono1
Channel
ADJUST
LOADCONTROL
47K
CA(FMon
someunits)

—4 —
OUTPUTCONNECTIONS
Threeoutputsareprovided:onetapeandtwomainoutputs.
TheTapeoutputmaybeusedforrecordingtapefromanysourceconnectedtotheAudioCompensator.
TheSelectorswitchandCompensationswitchareeffectiveatthisoutput.AdjustmentoftheBassandTreble
tonecontrolsandVolumecontrolmaybemadeformonitoringandwillnotaffecttherecordedsignal.The
Tapeoutputdeliversa signalof0.5volts.
TheMainoutputsareavailableattheoctalsocketbetweenpins#1and#2(pin#1isground),and
attheRETMApinjacklabeled"MAINOUTPUT."Theinter-unitcableconnectingtheC-4toanyMcintosh
poweramplifierusestheoctalsocketoutput.Thepinjackoutputmaybeusedfordrivinga secondpower
amplifierifsodesired.
TheMainandTapeoutputjacksarefedfromcathodefollowers.Theinputimpedanceofdevicescon-
nectedtotheseoutputsshouldbe50,000ohmsorgreater,andthecapacitivereactanceofaudiocablescon-
nectingthesedevicesshouldnotbelessthan8,000ohmsat20,000cycles.Thisisthereactanceofa capacityof
1000mmf.Audiocablehavinga capacityof25mmfperfootmaybe40feetlong,13.5mmfperfootcablemay
be75feetlong.
VOLTAGEANDRESISTANCECHART
Resistancesmeasuredtogroundwithpin#4ofinter-unitcablesocketshortedtopin#1.D.C.voltages
measuredwithVTVMtogroundusingD-8Apowersupply.
GUARANTEE
Weguaranteetheperformanceofthisequipmentandthemechanicalandelectricalworkmanshiptobe
freeofseriousdefectsfora periodof90days.Thisguaranteedoesnotextendtocomponentsdamagedbyim-
properuse,nordoesitextendtotransportationtoandfromthefactory.
PINNO.
1
2
3
4
5
6
7
8
9
PINNO.
1
2
3
4
5
6
7
8
9
PINNO.
1
2
3
4
5
6
7
8
9
V1
D.C.VOLTS
96V
0
1.07
0
11.7
94V
0
1V
V2
D.C.VOLTS
185V
94V
97V
11.7
0
185
20
66
V3
D.C.VOLTS
110
0
.82
0
11.7
340V
34V
118V
RES.W
300K
0-100K
4.3K
400K
1M
1.8K
RES. W
120K
450K
360K
120K
1.1M
110K
RES. W
370K
105K
1K
10K
1.1M
105K
MclNTOSHLABORATORY,INC.
2ChambersSt.
Binghamton,N.Y.,U.S.A.
InCanadaManufacturedUnderLicenseby
McCURDYRADIOINDUSTRIESLIMITED
22FrontStreet,WestToronto,Canada

TYPICALINSTALLATION
AUDIOCOMPENSATORC-4
TYPICALINSTALLATION
AUDIOCOMPENSATORC-4P
(SELFPOWERED)
MODELMC30POWERAMPLIFIER TUNER
PHONO
5-11-55
PHONO
MODELMC30POWERAMPLIFIER TUNER
SPEAKERS
MODELD-8A
POWERSUPPLY
SPEAKERS
3-11-55
TAPE

—6 —
CONTROLCURVESFORMODELC-8
AUDIOCOMPENSATOR
MclNTOSHLABORATORY,INC.
NARTBTAPE
PLAYBACKCOMPENSATION
BASSSWITCH"950"DEPRESSED
BASSTONE-1
TREBLETONE-2.5
AURALCOMPENSATOR
(ALLCHANNELS)
(PHONOCHANNELSONLY)
(PHONOCHANNELSONLY)COMPENSATIONCONTROLS(MIC& PHONOCHANNELSONLY)
TONECONTROLS
(ALLCHANNELS)
RUMBLEFILTER
(MIC& PHONOCHANNELSONLY)

Manufacturer
ALLEGRO
ALLIED
AMERICAN
RECORDING
SOCIETY*
ANGEL
ARIZONA
ATLANTIC*
AUDIOPHILE
BACHGUILD
BANNER*
BARTOK*
BOSTON*
BETHLEHEM
BLUENOTE*
CAEDMON*
CAPITOL
CAPITOL*
CANYON*
CAPITOL-CETRA*
COLOSSEUM*
CLASSIC
EDITIONS
CETRA-SORIA
COLUMBIA*
Speed
33
33
33
33
33
78
33
33
33
33
33
45
33
78
33
33
33
Compensafion
COL,LP
NAB
AES
ORTHO
NAB
ORTHO
COL,LP
629,16
ORTHO
AES
629,11
ORTHO
AES
AES
ORTHO
COL,LP
Manufacturer
COLUMBIA*
COLUMBIA*
CONCERTHALL*
CONTEMPORARY*
CORAL
COOK
DECCA*
DIAL
ELECTRA*
EMS*
EPIC*
ESOTERIC
EUROPEAN
FESTIVAL
FOLKWAYS*
GOOD
TIMEJAZZ
H.M.V.
HANDELSOC.
HAYDENSOC.
Speed
45
78
33
33
33
33
45
78
33
33
33
33
33
78
33
33
33
33
33
Compensation
NAB
COL,78
AES
NAB
ORTHO
COL,LP
629,16
AES
COL,LP
ORTHO
EUR,78
COL,LP
629,16
AES
ORTHO
COL,LP
Manufacturer
KAPP
KENDALL
LONDON*
LONDON*
LYRICHORD
MclNTOSH
MERCURY*
MGM*
MONTILLA*
NEWJAZZ
NOCTURNE
L'OISEAU-LYRE
NEWRECORDS
OCEANIC
OXFORD
OVERTONE
PACIFICJAZZ
PERIOD
PHILHARMONIA
POLYMUSIC
PRESTIGE
RIVERSIDE
ROMANY
Speed
33
33
33
78
33
33
33
45
78
33
45
78
33
33
33
33
33
33
33
33
Compensation
ORTHO
NAB
LON,LP
EUR, 78
NAB
ORTHO
AES
ORTHO
ORTHO
ORTHO
COL,LP
ORTHO
NAB
AES
NAB
ORTHO
Manufacturer
RACHMANINOFF
SOCIETY
RCAVICTOR
(OLD)
RCAVICTOR
(NewRIAA Curve)
REMINGTON
RENAISSANCE
SAVOY
STRADIVARI
TECHNICORD
TELEFUNKEN
TEMPO
TRANSRADIO
URANIA
VANGUARD
VOX*
WESTMINSTER
WALDEN
Speed
33
33
45
78
33
45
78
33
33
33
33
78
78
33
33
33
33
33
♦RIAA,ORTHO,
NewNARTB,
NewAES
uiedonrecordingi
modeilnce1955
Compentation
COL,LP
800,10
ORTHO
NAB
LON,LP
ORTHO
COL,LP
800,10
EUR, 78
NAB
COL, IP
ORTHO
COL,LP
ORTHO
ORTHO
RECORDCOMPENSATION
withthe
C-4EQUALIZERPRE-AMPLIFIER
TheMclNTOSHC-4Equalizercanbesettocompensatethere-
cordingcharacteristicusedbytherecordmanufacturer.Usethe
"Compensator"knobpositionindicatedonthischart.Makefurther
fineadjustmentoftonewiththe"Bass"and"Treble"controlsto
suityourindividualpreference.(Turningtotheleftof0 addsde-
emphasis;turningtotherightof0 addsemphasis.)

MountingInstructionsforModelsC-4,C-4P,C-8andC-8FAudioCompensators
1.Placetemplateinposition.
2.Drilllargeholesasillustrated.Centersareprovidedfor3/4",l",and1-1/4"drills.
3.Cutoutinnerrectanglewithkeyholesaw.
4.Drillcornermountingholes:5/32''drillfor#6machinescrew;1/16"drillfor#6wood
screw.
5.InsertC-4,C-4P,C-8orC-8Pthroughrectangularcut-outandfasteninpositionusing
woodormachinescrewsasdesired.
6.DrillmountingholesforModelD-8powersupplyandfasteninposition.Thepowersup-
plymaybemountedinanyposition,butshouldbeplacedatleasttwofeetfromtheunit
andphonographcartridges.