McIntosh C-8S User manual

INSTALLATIONforC-8S
TheC-8SProfessionalAudioCompensatorwithStereoControlisa
completeC-8Compensatorwiththeadditionofa "STEREOMODESELECTOR
SWITCH,""STEREOBALANCE"andgangeddual"VOLUMECONTROLS".
ShippedwiththeC8saretwo6 footshieldedleadsandone3 footshield-
edlead.Thesewillbeusedininterconnectingthesystem.
TointerconnecttheC-8andC-8Sformonaural-stereoreproduction,
completethefollowingprocedure.UsetheC-8fortheleftchannel
andtheC-8Sfortherightchannel.
TheC-8Isfirstmodifiedasfollows:
1.)Theheavyinter-unitcableconnectingtheC-8tothepower
amplifierIsdisconnectedattheamplifierend.
2.)Witha pairofcuttingpliers,removepin#2fromtheoctalplug
oftheinter-unitcable.Ina monauralsystempin#2carriesthesignal
fromthepreamplifiertothepoweramplifier.Ina stereosystemthe
signalmustbeobtainedfromthemainoutputjackonthebackofC-8.
3.)Afterremovingpin#2theinter-unitcableIsreconnectedtothe
poweramplifier.
4.)OnC-8'swithserial#10600andabovetheinputmarked"MIC"can
besimplyconvertedtopreamplificationandequalizationfortapeheads
bycuttingonewireontheinputselectorswitch,(seefigureB.)
Onserialnumbersbelow10600theconversionmustbedoneatthefactory
Thecostoffactoryconversionis$5.00.Tapeheadscan,ofcourse,
beusedin"PHONO#1"onallC-8compensatorswithoutanyconversion.
Forpropertapeheadconnectionseethetopparagraphonpage4 ofthe
C-8Instructionmanual.
(A.)

Nowconnecttheprogramsourcesinthefollowingfashion:
1.)Plugoneendofthe3 footshieldedleadintothejackmarked
"MAINOUTPUT"locatedonthebackpaneloftheC-8.
2.)TheC-8"VOLUME"controlonthefrontpanelisturnedfully
clockwise.ThechangesinvolumewillbecontrolledbytheC-8Sganged
"VOLUME"control.
3.)Inserttheleftchannelphonocartridgeleadin"PHONO#2"onthe
C-8.
4.)Ifa tapedeckisusedforstereoplayback,insertleftchannel
leadinto"MIC"inputoftheC-8,serial#10600andabove,afterconver-
sionasinsectionA,step#4above.Thisinputisterminatedat100,000
ohms.N.A.R.B.tapeplaybackequalizationisachievedbydepressingthe
BassCompensationswitchlabeled"950",adjustingthe"BASS"tonecontrol
to- 1,andadjustingthe"TREBLE"tonecontrolto-2.5.
Ifa stereotapeplaybackwithpreamplifiersisused,insertthe
leftoutputinthechannelmarked"TAPE".
NextinterconnecttheC-8S:
1.)Plugtheheavyinter-unitcablefromtheC-8Sintheoctalsocket
marked"Pre-Amp"ontherightpoweramplifier.
2.)Thelooseendofthe3'shieldedlead(sectionB,step#1)from
theC-8"MAINOUTPUT"ispluggedintothe"LEFTSTEREOIN"ontheC-8S.
3.)Interconnectbymeansofoneofthe6'shieldedcablesbetween
thejackmarked"LEFTSTEREOOUT"ontheC-8Sandthe"0.5VOLT"input
oftheleftpoweramplifier.
4.)Interconnectbymeansoftheotherofthe6'shieldedcablesbetween
the"MAINOUTPUT"ontheC-8Sandthe"0.5VOLT"inputontheright
poweramplifier.
5.)PlugtheA.C.cordfromtheC-8intooneoftheauxiliaryA.C.
receptaclesontheC-8S.
6.)TheA.C.cordsfrombothpoweramplifierscannow"bepluggedinto
theauxiliaryA.C.plugsontheirrespectivepreamplifiers.Theon-off
switchonthevolumecontroloftheC-8Snowcontrolsturningonthe
entiresystem.
(c.)
(B.)
-2-

ConnecttheprogramsourceequipmenttotheC-8Sasfollows:
1.)PlugtherightchannelphonocartridgeleadintotheC-8Sinput
marked"PHONO#2".
2.)Connecttheoutputoftherightchanneltapeheadtotheinput
marked"TAPEHEAD".ForN.A.R.B.equalizationfroma tapehead,depress
thebasscompensationswitchlabeled"950",adjust"BASS"tonecontrol
to- 1,and"TREBLE"tonecontrolto- 2.5.
3.)Ifa taperecordedwithpreamplifiersisused,plugtheoutputof
therightchannelintotheinputmarked"TAPE".
4.)Ifa monauralcartridgeisused,plugitinto"PHONO#1".
5.)Connecta tuneroutputtoinputmarked"TUNER",
Thebalanceofthestereosystemwillbemaintainedinallmodesof
operationbyfollowingthesesystembalancinginstructions:
1.)Turninputselectorswitchesonbothpreamplifiersto"PHONO#2".
2.)Turnthestereo"MODE"selectorswitchto"MONRIGHT".
3.)Adjustthe"BALANCE,""BASS,"and"TREBLE"controlsto12o'clock.
4.)AdjusttheRECORDCOMPENSATOR"toRIAAsettings.
5.)Adjustthe"INPUTLEVELCONTROL"onbothcompensator"PHONO#2"
channelstotallyclockwise.A monauralrecordisusedforcorrectly
balancingthesystem.TurnupthevolumecontrolontheC-8S.Withthe
modeselectorswitchin"MONRIGHT"thesamesignalwillbeheardfrom
bothloudspeakers.
6.)Ifthesoundfromeachloudspeakerisnotofequalloudnessadjust
thecontrolmarked"GAIN"ononepoweramplifieruntilthesoundsfrom
theloudspeakersareofequalintensity.DonotusetheBalanceControl
forthisadjustment.
-3-
(E.)
(D.)

-4 -
7.)Withthemonauralrecordplaying,standona lineapproximately10
feetinfrontofandmidwaybetweentheloudspeakers.Themainsourceof
soundshouldappeartobedirectlyinfrontofyou.Ifthemusicsounds
aredividedtheloudspeakersareoutofphase.Correctthisbyreversing
theloudspeakerleadsononeloudspeakeronly.Thepoweramplifiersnow
areinphaseandbalanced.Donotchangethe"GAIN"controlonthe
poweramplifiersinanyofthefollowingsteps.
8.)Nextbalanceforequaltonequalityoneachsidebymovingthe
"MODE"switchbetween"STEREOLEFT"and"RIGHT".Comparethehigh
frequencyresponseoneachloudspeakerfirst.Adjustthe"TREBLE"'
tonecontrolononesideonlyuntilthesurfacenoisefromtherecord
oneachsideisofequalintensity.
9.)Nextmakea carefulcomparisonoflowfrequencyresponse.While
switchingbetween"STEREOLEFT"and"RIGHT11adjustthe"BASS"tone
controlononecompensatoruntilthebassoutputisequalfromboth
speakers.
10.)Removethemonauralrecord.Nextplaya stereorecord.Turnthe
C-8Svolumecontroluptoroomvolumeandadjustthe"BALANCE"control
forbalancedstereoresults.Thebalancecontrolisdesignedtoadjust
forunequalprogramsources,andmaintainbalanceofthesystemwhen
switchingbetween"STEREONORM"and"REV".
InstallationPrecautions:
Cautionmustbeexercisedintheinstallationtokeepthegroundleadfrom
eachchannelofthestereocartridgeorstereotapeheadsseparatetoprevent
groundloopsandhum.