McIntosh MC-60 User manual

INSTRUCTIONMANUAL
MclNTOSHMODELMC-60
60WATTPOWERAMPLIFIER
TypeA-121
SerialNo.5F846andabove
MclNTOSHLABORATORY,INC.
2ChambersSt.Binghamton,N.Y.
U.S.A.

ELECTRICALANDMECHANICALSPECIFICATIONS
SpecificationsfortheMclntoshModelMC-60AudioAmplifier
PowerSupply
PowerConsumption
PowerOutput
InputLevel
FrequencyRange
HarmonicDistortion
IntermodulationDistortion
ImpulseDistortion
NoiseandHumLevel
DampingFactor
InputImpedance
OutputImpedance
PhaseShift
TubeComplement
AuxiliaryEquipmentConnection
Size
Weight
Finish
117/125volts,50/60cycles
280wattsat60wattsoutput
155wattsatzerosignaloutput
60wattscontinuous
Input#1,0.5 voltsto30volts,withgaincontrol
Input#2,2.5 volts(forusewithMclntoshAudio
CompensatorsandPre-Amps)
20to30,000cycles± .1dbat60wattsoutput
16to60,000cycles± .5dbat60wattsoutput
1.0to100,000cycles± 1.0dbat30wattsoutput
Lessthan0.5%at60wattsoutputorless,20
to20,000cycles.
Lessthan0.5%instantaneouspeakpowerisbe-
low120watts
Negligible
90dbormorebelowratedoutput
12orbetterfor4,8,and16ohmoutput,16
for600ohms
0.5 megfor0.5 voltinputand0.13megfor
2.5 voltinput,20cyclesto40KC
4,8,16,83(70.7volts)and600ohms(600ohm
isbalancedtoground)
±8°20-20.000cycles
Rectifier:
Pre-Amp:
PhaseInverter:
VoltageAmp:
Driver:
Output:
2-5U4GB
12AX7
12AU7
12BH7
12AX7
2KT-88/6550
DesignedtopowerC-4,C-8andotherMclntosh
pre-amplifiers
14"x 10"x 8"high,chassistypeconstruction
46poundsnet
ChromeandBlack

DESCRIPTION
TheMclntoshModelMC-60isa 60watthighfidelitypoweramplifierdesignedforhome
entertainmentsystemsandprofessionalapplicationswherehighpoweranddistortionfree
performanceisrequired.TheModelMC-60,likeallotherMclntoshpoweramplifiers,uses
theexclusiveMclntoshhighefficiecnyoutputcircuitandbifilaroutputtransformertoobtain
thehighstandardofperformancefoundinthisamplifier.Someofthemoreimportantchar-
acteristicsoftheamplifierare;lessthan0.5%harmonicdistortionatanypoweroutputupto
60wattsandatanyfrequencyintheaudiospectrum,20to20,000cps;lessthan0.5%inter-
modulationdistortionforallpowerlevelsupto120instantaneouspeakwatts;andnoiseand
humlevel90dbormorebelowtheratedoutputlevel.
TheMC-60hastwohighimpedanceinputsandmaybeoperatedfromanysignalsource
delivering0.5 voltsormore,ordirectlyfroma MclntoshAudioCompensatororPre-Ampli-
fier.Outputimpedanceof4,8 and16ohmsareprovidedfordirectconnectiontoloud-
speakers.Additionaloutputsfor83ohms(70.7volts)and600ohmsareprovidedforuse
withmultiplespeakersystems,lines,etc.
INSTALLATION
Location
TheMC-60shouldbelocatedina well-ventilatedarea.Iftheamplifierishousedina
cabinetorotherenclosure,holesmustbeprovidedforaircirculation.
InputConnections
1.Whena MclntoshAudioCompensatororPre-Amplifierofthenon-selfpoweredtype
isusedwiththeMC-60,plugthepre-amplifier'soutput-powercordintothe"PRE-AMP
INPUT"receptacleontheMC-60andturnthe"GAIN"controlfullycounterclockwise.This
receptaclesuppliestherequiredplateandfilamentpowertothepre-amplifierequipmentas
wellasprovidingthenecessaryaudioconnections.
Forpre-amplifierinstallation,adjustmentandoperationrefertothepre-amplifier's
instructionmanual.
2.Whenusinga self-poweredMclntoshAudioCompensatororPre-Amplifier,connect
theaudiooutputfromthepre-amplifiertotheinputoftheMC-60usingthecablesupplied
withthepre-amplifier.Turnthe"GAIN"controlfullycounterclockwise.
3. When a signal source of0.5 volts or more is used to drive the MC-60, such asthe
outputofa tuner,taperecorder,orotherpre-amplifiers,plugthesourceintothe"0.5 VOLT"
pinjackreceptacleorconnecttothe"0,5 VOLT"and"GND"screwterminals.Usethe
"GAIN"controltoobtainthedesiredoperatinglevel.
Ifdesired,thesignalsourcemaybewiredtoanoctalplugforinsertionintheoctal
"Pre-AmpInput"receptacle.Inthiscaseconnecttheinputleadtopin#5andtheground
leadtopin#1.Whenusingthisconnectionthesourcemustnothavea DCoutputcomponent.
OutputConnections
TheMC-60hasoutputimpedancesof4,8 and16ohmsavailableateitherthescrew
terminalconnectorortheoutputsocket.Inaddition,a 600ohmoutput(balancedtoground)
isavailableattheoutputsocket.Seeschematicdiagramforsocketconnections.
Itisimportantthattheloudspeakerorotherloadbeproperlymatchedtotheamplifier
ifbestperformanceistobeobtained.Becausemanyloudspeakersdonothavevoicecoilim-
pedancesexactlymatching 4,8 and16 ohms, the followingtable lists suggested connections
forthebestimpedancematching.
SpeakerImpedance
Connectto
3.2 to6.5 ohms
4ohms6.5 to13ohms 8ohms13to32ohms 16ohms

WARNING:OutputplugswiredforMclntosh20W-2and50W-2amplifiersmustnotbe
usedwiththeMC-60withoutrewiringtheplug.
OutputconnectionsfortheMC-30arethesameasthosefortheMC-60.
PowerConnections
The MC-60 operatesfrom any110to130 volt 50-60 cycles power line. (When contin-
uoususeiscontemplatedon120to130linevoltsthetransformerprimaryshouldbore-con-
nectedusingthe125volttap.)
WhentheMC-60isusedwithMclntoshPre-Amplifierequipment,tuners,orother
associatedequipment,theMC-60powercordmaybepluggedintothereceptacleattherear
oftheseunits.WhenthusconnectedthepowerswitchoftheseunitscontrolstheMC-60.
GUARANTEE
Weguaranteetheperformanceofthisequipmentaridthemechanicalandelectrical
workmanshiptobefreeofdefectsfora periodof90days.Thisguaranteedoesnotextend
tocomponentsdamagedbyimproperusenordoesitextendtotransportationtoandfromthe
factory.
SERVICEINFORMATION
AllMclntoshequipmentisdesignedforlongtroublefreeoperation.Allcomponents
areofthehighestqualityandareconservativelyoperated.Iftroubledevelopstheamplifier
maybeservicedbyyourfranchiseddealer,a competentserviceman,orreturnedtothe
factory.Equipmentwillnotbeacceptedatthefactoryunlessfactoryreturnauthorization
isfirstreceived.Thefollowingchartofoperatingvoltagesandresistancesisofferedasa
guideforservicingtheunit.Allvoltagesandresistancesaremeasuredtochassisexcept
thosewithasterick{*).Thesearemeasuredtochassiswithpin#2ofeither5U4GBground-
ed.VoltagesaremeasuredwithhighimpedanceVTVMNOTE- UNITMUSTBETURNED
OFFWHENMEASURINGRESISTANCES.
VOLTAGEANDRESISTANCECHART
Tube
12AX7
(Input)
12AU7
12BH7
PinNo.
1
2
3
4& 5
6,7,8
9
1
2
3& a
4& 5
6
7
9
1
2
3& 8
4& 5
6
7
9
DCVolts
NoSignal
134
0
1.2
Fil
-
Fil
270
134
138
Fil
270
110
Fil
340
0
16
Fil
340
0
Fil
DCVolts
at60Wout
120
0
1.1
6.3 V.actopin9
-
-
235
120
126
6.3V actoPin9
235
100
_
290
0
14
6.3VactoPin9
290
0
-
ACVolts
at60Wout
1.5
.4
.4
-
-
-
11
1.5
0.6
-
11
0
_
148
11
0.32
148
11
-
Resistance
UnitOff
330K*
1M
3.3K
0to70
-
0to70
40*
330K*
18K
0to70
43K*
2.6M*
0to70
12K*
20OK
1.2K
0to70
12K*
200K
0to70

Tube
12AX7
KT-88/6550
(Bothtube*)
5U4GB
(Bothtubes)
PinNo.
1
2
3
4& 5
6
7
a
9
1
2
3
4
5
6
7
8
1
2
3
4
5
6
7
8
DCVolts
NoSignal
435
-46
-45
Fil
435
-46
-45
Fil
0
Fil
435
435
-45
-
Fil
.8
-
440
-
375AC
-
375AC
-
440
DCVolts
at60Wout
365
-46
-45
6.3V actoPin9
36S
.46
-45
-
0
6.3V.actoPin7
365
365
-45
-
-
2.5
-
380
-
370AC
-
370AC
-
380
ACVolts
at60Wout
106
148
148
-
106
148
148
-
0
-
106
110
148
-
-
110
-
8.9(ripple)
370
370
Resistance
UnitOff
45*
1M
270K
0to70
45*
1M
27OK
0to70
-
0to70
45*
45*
270K
-
0to70
12
-
0*
-
15
-
15
-
0*
Pinsnotlistedareeitherfilaments,havenovoltageorarenotused.
U.S.PatentsNo.2.477,074;2,545,788;2,646.467;2,654,058otherspending.
MclNTOSHLABORATORY,INC.
2ChambersStreet
Binghamton,N.Y.,U.S.A.
InCanada:ManufacturedUnderLicensebyMcCurdyRadioIndustries,Ltd.
22FrontStreetWest,Toronto,Canada

OUTPUT
CONNECTIONS
USING
OCTAL
SOCKET
4ohms - pins 1 & 2 8ohms - pins 1 & 3 16ohms- pins 1 & 4
500/600
ohms
-
pins
7 & 8
(pin
6 is CT and
ground)
70.7
volts-
pins
5 & 6
(pin
6is
ground)
PRE-AMPLIFIER
INPUT
SOCKET
CONNECTIONS
-Ground
-
Pre-Amp
Input
(2.5V)
-Notused
-+360V at 3.5 mA
-
Pre-Amp
input
(0.5V)
-not used
7& 8 -
6.3V
at 1Amp
R1250KPOT(GAIN ADJ.) R2
100K
R327K
R41M
R5
3.3K
R6685%
R7
100K
R8
330K
R9
680K
R10
18K
1W
R11
2.2M
R1227K5% R1330K5% R14220K
R15
220K
R16330K
R1712K*2W R18
12K*
2W
R191.2K R2056K5%
R21 1M
R221M R23
100K
5%
R24 56K R25 56K
R2656K R27 56K R282201W R292201W
R30
1.3K
5%
R3110K10W R32 10K 2W R33250OHMPOT(HUM ADJ.)
*Matched to within 1%
CH1 Plate Choke CH2PlateChoke C1
.1mF,
200V
C2100mF,12V
C3 8mF, 250V
C4
.22mF,
400V
C5
,047mF,600V
C6
.047mF,
600V
C7
.22mF,
600V
C8
.22mF,600V
C9
.47mF,
200V
C10
.47mF,200V
C11
470mF,
500V
C12A
35mF,
500V
C12B
80mF,500V
C12C15mF,450V C13A35mF,500V
C13B80mF,500V C13C 15mF,450V
C14
8mF,
250V
SERIAL
NO
3FB46
AND
ABOVE
Pin 1
Pin 2
Pin 3 Pin 4 Pin 5 Pin 6
Pins

038-177
Be102002