McIntosh MR 7083 User manual

IMPORTANTSAFETYINSTRUCTIONS
THESEINSTRUCTIONSARETO
PROTECTYOUANDTHEMclNTOSH
INSTRUMENT.BESURETO
FAMILIARIZEYOURSELFWITHTHEM.
1.Readallinstructions- Readthesafetyand
operatinginstructionsbeforeoperatingthe
instrument.
2.RetainInstructions- Retainthesafetyand
operatinginstructionsforfuturereference.
3.Heedwarnings- Adheretowarningsand
operatinginstructions.
4.FollowInstructions- Followalloperatinganduse
instructions.
WARNING:TOREDUCERISKOFFIREOR
ELECTRICALSHOCK,DONOTEXPOSETHIS
INSTRUMENTTORAINORMOISTURE.
5.PowerSources- Connectthepowersupplyonlyto
thetypedescribedintheoperatinginstructionsor
asmarkedontheunit.
6.Power-CordProtection- Routepower-supplycords
sothattheyarenotlikelytobewalkedonor
pinchedbyitemsplaceduponoragainstthem,
payingparticularattentiontocordsatplugs,
conveniencereceptacles,andthepointwherethey
exitfromtheinstrument.
7.Ventilation- Locatetheinstrumentforproper
ventilation.Forexample,theinstrumentshould
notbeplacedona bed,sofa,rug,orsimilar
surfacethatmayblockventilationopenings;or,
placedina built-ininstallation,suchasa bookcase
orcabinet,thatmayimpedetheflowofair
throughtheventilationopenings.
8.Heat- Locatetheinstrumentawayfromheat
sourcessuchasradiators,heatregisters,stoves,or
otherappliance(includingamplifiers)thatproduce
heat.
9.WallorCabinetMounting- Mounttheinstrument
ina wallorcabinetonlyasdescribedinthe
ownersmanual.
10.WaterandMoisture- Donotusetheinstrument
nearwater- forexample,neara bathtub,
washbowl,kitchensink,laundrytub,ina wet
basement,orneara swimmingpool,etc.
11.Cleaning- Cleantheinstrumentbydustingwitha
drycloth.Cleanthepanelwitha clothmoistened
witha windowcleaner.
12.ObjectandLiquidEntry- Donotpermitobjectsto
fallandliquidstospillintotheinstrumentthrough
enclosureopenings.
13.NonusePeriods- Unplugthepowercordfromthe
ACpoweroutletwhenleftunusedfora long
periodoftime.
14.DamageRequiringService- Servicemustbe
performedbyqualifiedservicepersonnelwhen:
A.Thepowersupplycordortheplughasbeen
damaged;or
B.Objectshavefallen,orliquidhasbeenspilled
intotheinstrument;or
C.Theinstrumenthasbeenexposedtorain;or
D.Theinstrumentdoesnotappeartooperatenor-
mallyorexhibitsa markedchangeinperformance;
or
E.Theinstrumenthasbeendropped,orthe
enclosuredamaged.
15.Servicing- Donotattempttoservicebeyondthat
describedintheoperatinginstructions.Allother
serviceshouldbereferredtoqualifiedservice
personnel.
16.GroundingorPolarization- Donotdefeatthe
inherentdesignfeaturesofthepolarizedplug.
Non-polarizedlinecordadaptorswilldefeatthe
safetyprovidedbythepolarizedACplug.
17.CAUTION:TOPREVENTELECTRICALSHOCKDO
NOTUSETHIS(POLARIZED)PLUGWITHAN
EXTENSIONCORD,RECEPTACLEOROTHER
OUTLETUNLESSTHEBLADESCANBEFULLY
INSERTEDTOPREVENTBLADEEXPOSURE.
ATTENTION:POURPREVENIRLESCHOCS
ELECTRIQUESPASUTILISERCETTEFICHE
POLARISEEAVECUNPROLONGATEUR,UNEPRISE
DECOURANTOUUNEAUTRESORTIEDE
COURANT,SAUFSILESLAMESPEUVENTETRE
INSEREESA FONDSANSENLAISSERAUCUNEPAR-
TIEA DECOUVERT.

Thelightningflashwitharrowhead,withinan
equilateraltriangle,isintendedtoalerttheuserto
thepresenceofuninsulated"dangerousvoltage"
withintheproduct'senclosurethatmaybeof
sufficientmagnitudetoconstitutea riskofelectric
shocktopersons.
CAUTION:TOPREVENTTHERISKOFELECTRIC
SHOCK,DONOTREMOVECOVER(ORBACK).NO
USER-SERVICABLEPARTSINSIDE.REFERSERVICING
TOQUALIFIEDPERSONNEL.
Theexclamationpointwithinanequilateraltriangle
isintendedtoalerttheusertothepresenceof
importantoperatingandmaintenance(servicing)
instructionsintheliteratureaccompanyingthe
appliance.
Theserialnumber,purchasedate,andMclntosh
LaboratoryServiceContractnumberareimportantto
youforpossibleinsuranceclaimorfutureservice.
Recordthisinformationhere.
SerialNumber
PurchaseDate
ServiceContractNumber
Uponapplication,MclntoshLaboratory
providesa ServiceContracttotheoriginal
purchaser.YourMclntoshAuthorized
ServiceAgencycanexpediterepairswhen
youprovidetheServiceContractwiththe
instrumentforrepair.

Contents
INTRODUCTION3
INSTALLATION4,5
HOWTOCONNECT6,7
CONNECTINGDIAGRAM8
FRONTPANELCONTROLS9,10
PERFORMANCELIMITS11
PERFORMANCECHARTS12
TECHNICALDESCRIPTION13,14
BLOCKDIAGRAM15
YourMR7083AM/FMDigitalTunerwillgiveyou
manyyearsofsatisfactoryperformance.Ifyouhave
anyquestions,pleasecontact,
CUSTOMERSERVICE
MclntoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903-9990
Phone:[phone]
TakeAdvantageof3 Yearsof
ContractService.. .
FillintheApplicationNOW.
MclNTOSHTHREEYEARSERVICECONTRACT
An application forA THREE YEARSERVICE CONTRACT is included with thismanual.
Thetermsofthecontractare:
1.Iftheinstrumentcoveredbythiscontract
becomesdefective,Mclntoshwillprovideallparts,
materials,andlaborneededtoreturnthe
measuredperformanceoftheinstrumenttothe
originalperformancelimitsfreeofanycharge.The
servicecontractdoesnotcoveranyshippingcosts
toandfromtheauthorizedserviceagencyorthe
factory.
2.AnyMclntoshauthorizedserviceagencywill
repairallMclntoshinstrumentsatnormalservice
rates.Toreceivethefreeserviceundertheterms
oftheservicecontract,theservicecontract
certificatemustaccompanytheinstrumentwhen
takentotheserviceagency.
3.Alwayshaveservicedonebya Mclntosh
authorizedserviceagency.Ifthe instrument is
modified or damaged as a result of unauthorized
repair the service contract will be cancelled.
Damagebyimproperuseormishandlingisnot
coveredbytheservicecontract.
4.Theservicecontractisissuedtoyouasthe
originalpurchaser.Toprotectyoufrom
misrepresentationthiscontractcannotbe
transferredtoa secondowner.
5.UnitsinoperationoutsidetheUnitedStatesand
CanadaarenotcoveredbytheMclntoshFactory
ServiceContract,irrespectiveoftheplaceof
purchase.NorareunitsacquiredoutsidetheUSA
andCanada,thepurchasersofwhichshould
consultwiththeirdealertoascertainwhat,ifany,
servicecontractorwarrantymaybeavailable
locally.
Copyright1991© byMclntoshLaboratoryInc.
2

TheMclntoshMR7083isa highqualityAM/FM
Tunerwhosedesignhasbeengovernedbyinsistence
onhighperformancewithlonglife,greatflexibility
andsensitivity.
Youwillderivethegreatestenjoymentandmost
satisfactionfromyourMR7083whenyouunderstand
itsoperationsandfunctions.Yourtimeinvestednow
willreturnaddedvaluetoyoubecauseyouwillget
thebestresultsfromyourMR7083.
Mclntoshhasearnedworldrenownforitstechno-
logicalcontributionsforimprovedsound.Whenyou
boughtMclntosh,youboughtnotonlyhightechno-
logy,youboughttechnologicalintegrityprovenby
time.TheMclntoshMR7083Tuneriscontinuing
evidenceofMclntoshtechnologicalsuperiorityand
integrity.
Musicreproducinginstrumentsthatcarrythe
Mclntoshnamehavealwaysbeendesignedfor
technologicalleadershipandtomaintainthe
Mclntoshreputationfordurability,longlife,andbest
sound.Mclntoshhashadtoearntheforemost
reputationforqualityperformance.Mclntoshhas
provideduser-orientedfacilitiesandappearance,and
Mclntoshdesignprovidesforeaseofmaintenanceor
repair.Thesefundamentalelementsareincorporated
intheMclntoshMR7083AM/FMTuner,theeasiest
tooperateyetwithextensiveusefulfeatures.
YourMclntoshMR7083,aboveallothers,will
deliverthebestsoundandthegreatesteaseofuse
witha highdegreeofflexibility.
SomeofthefeaturesthatsettheMR7083apart
fromtheordinaryare:
TheadvancedAM/FMtunerdesignoftheMR7083
displaysthestationfrequenciesdigitally.Stationsare
selectedeasilyinanyoneoftheseways:A.usethe
manualtuningknob,B.usetheSCANupordown
touchbuttons,C.usethepresetstationtouchbuttons
or,D.usetheSEARCHwhichwillpreviewthepreset
stationsfor5 secondseach.
ThesoundenhancingSPATIALaudioprocessor
provides an aural picturethat is more"stereo like"
inqualityanddimension.Onnoisy,weakFMsta-
tionsorAMstations,SPATIALprovidesreduced
noiseandretainsa broadstereo-likesound.
HighqualitytaperecordingsofFMbroadcastscan
bemadewithouttheinterferencethatstereotrans-
missionscancause.Carefullydesignedsuppression
circuitseliminatethepotentialforstereocarrier
noisewhenmaking"offtheair"taperecordings.
AuniquePhaseLockedLoopMultiplexdecoder
delivers STEREO FM with lowerdistortion,lower
noise,andbetterseparation.
ThemostusefulandflexibleAMantennasystem
willsuityourparticularinstallation.A low-impedance
loopstickwill,inmostlocalareas,provideAM
signalswhilerejectingnoiseandinterference.In
noisyAMlocations,anexternalnoisereducing,noise
canceling,shieldedloopwillprovideidealinput
signal.Ina remotelocation,a conventional'long
wire'antennacanbeused.
TheMR7083canberemotecontrolledfroma
MclntoshIRRemoteControlsystem.
Allinall,yourselectionoftheMR7083willbe
reinforcedbyyourday-to-dayuseofthissuperb
instrument.Goodlistening.
INTRODUCTION3

Thetrouble-freelifeofanelectronicinstrumentis
greatlyextendedbyprovidingsufficientventilationto
preventthebuild-upofhighinternaltemperatures
thatcausedeterioration.Allowenoughclearanceso
thatcoolaircanenteratthebottomofthecabinet
andbeventedfromthetop.Withadequate
ventilationtheinstrumentcanbemountedinany
position.Therecommendedminimumspacefor
installationis15inches(38.1cm)deep,17inches
(43.2cm)wide,and6 inches(15.2cm)high.
TheMR7083maybeinstalledina Mclntosh
cabinetorcustominstalledinfurnitureofyour
choice.Alwaysprovideadequateventilation.Never
placeitaboveheatgeneratingcomponentssuchas
highpoweredamplifiers.Provide1½inches(3cm)of
spaceabovethepreamplifiersoasnottointerfere
witha coolingairflow.
CUSTOMINSTALLATION
ThePANLOCsystemofinstallingequipment
convenientlyandsecurelyisa productofMclntosh
research.ThePANLOCbuttonsonthefrontpanel
willlocktheunitfirmlyinplacewhentheyare
turnedapproximatelyonequarterturnclockwise.A
counterclockwiseturnofthePANLOCbuttons
unlocksthechassisfromitsmounting.
Toinstalltheinstrumentina Mclntoshcabinet,
followtheinstructionsthatareenclosedwiththe
cabinet.Foranyothertypeofinstallation,follow
theseinstructions:
1.UnpackfromCarton
OpenthecartonandremovethePANLOCbrackets,
hardwarepackage,andmountingtemplate.Remove
theinstrumentfromitsplasticbagandplaceit
upsidedownontheshippingpallet.Unscrewthe
fourplasticfeetfromthebottomofthechassis.
2.MarktheCabinetPanel
Tapethemountingtemplateinpositiononthe
cabinetpanelwheretheinstrumentistobe
installed.Thebrokenlinesthatrepresenttheoutline
oftherectangularcutoutalsorepresenttheoutside
dimensionsofthechassis.Makesuretheselines
clearshelves,partitions,oranyequipment.Withthe
templateinplace,firstmarkthesixA andB holes
andthefoursmallholesthatlocatethecornersof
thecutout.Then,jointhefourcornermarkingswith
pencillines,usingtheedgeofthetemplateasa
straightedge.
3.DrillHoles
Usea drillwitha 3/16inch(5mm)bitheld
perpendiculartothepanelanddrillthesixA andB
holes.Then,usinga drillbitslightlylargerthanthe
tipofyoursawblade,drilloneholeateachoftwo
diagonallyoppositecorners.Theholesshouldbarely
touchtheinsideedgeofthepenciledoutline.Before
takingthenextstep,makesurethatthesixA andB
holeshavebeendrilled.
4INSTALLATION
MOUNTINGTEMPLATE

4.SawthePanelCutout
Sawcarefullyontheinsideofthepenciledlines.
Firstmakethetwolongcutsandthenthetwoshort
cuts.Aftertherectangularopeninghasbeencutout,
usea filetosquarethecornersandsmoothany
irregularitiesinthecutedges.
5.InstalltheMountingStrips
Inthehardwarepackagearetwomountingstrips,
andtwo1-1/4"(31.8mm)blacklongscrewsthathave
aflathead.Usethesescrews,oneoneachend,to
fastenthemountingstrips.Theyareattached
throughthecenterhole,markedB onthetemplate.
Makesurethescrewheadsaredrawnflushor
slightlyintothewoodbeforeattachingthePanloc
brackets.
6.AttachthePANLOCBrackets
Inthehardwarepackagearetwosetsofscrews.For
panelslessthan1/2"(12.7mm)thick,usethe3/4"
(19.1mm)longscrews;forthickerpanels,usethe
1-1/4"(31.8mm)longscrews.
UsingtwoscrewsoftheproperlengthintheA
holesoneachside,attachthePANLOCbracketsto
thecabinetpanel;theshortflangeismounted
againstthefront(face)ofthecabinetpanel.The
screwspassthroughthePANLOCbracketflange,the
cabinetpanel,andthenthroughthemountingstrips
previouslymounted.
7.InstalltheInstrument
GuidetheACpowercordthroughthepanelopening
tothebackofthecabinet;then,slidetheinstrument
intotheopeningcarefullysothattherailsonthe
bottomofeachsideofthechassisengagethetracks
onthemountingbrackets.Continuetoslidethe
instrumentintothecabinetuntilthefrontpanelis
flushwiththecabinetpanel.TurnthePANLOC
buttonsatthelowerleftandrightcornersofthe
instrumentpanelclockwisetolocktheunitfirmlyin
thecabinet.TurnthePANLOCbuttons
counterclockwisetounlocktheinstrument.Itcan
thenslideoutwardtopermittheremoval.
INSTALLATION5

Foldoutthephotographsontheinsideoftheback
cover. They will assist youin connecting theMR 7083
toyoursystem.Thenumbersonthephotographsrefer
totheparagraphsthatfollow.
ThebackpaneloftheMR7083hasconnectors
labeledAUDIOOUTPUT,REMOTECONTROL,AM
antenna,75OHMFMantenna,SCOPEOUT,andAC
powerusedtointerconnectwithassociated
equipmentandtheACpowerline.Useshielded
cablestoconnecttheoutputsignaltoa preamplifier
orpoweramplifier.Tominimizethepossibilityof
hum,theshieldedcablesshouldbeofparallel
constructionorlooselytwistedtogetherandlocated
awayfromthespeakerconnectingcablesandAC
powercords.Becertaintousegoodqualityshielded
cablesforallinterconnections.Yourdealercan
adviseyouonthekindandlengthofcablesthatwill
bestsuityourinstallation.
1.AUDIOOUTPUT
UsetheFIXEDAUDIOOUTPUTjacksonthe
rearpaneltofeedprogramtoequipmentwhich
hasitsownvolumecontrol.Theoutputlevelisa
nominal1.2voltfor100%FMmodulation.The
lowoutputimpedancepermitslongaudiocables
tobeusedwithouta lossofhighfrequenciesdue
tocablecapacity.
2.VARIABLEOUTPUT
TheVARIABLEOUTPUTjacksareusedwhenyou
wishtoadjustthetuneroutputleveltomatch
otherprogramsources.Thelowoutput
impedancepermitslongaudiocablestobeused
withouta lossofhighfrequenciesduetocable
capacity.Theoutputleveliseasilyadjustedby
turningtheoutputlevelscrewwitha screwdriver.
3.REMOTECONTROL
TheREMOTECONTROLconnectorisdesigned
forusewiththeMclntoshinfraredremotecontrol
systems.Withthesesystems,youcan,froma
hand-heldremotecontrol,turnonthetunerand
thesystem,selectfromeightpreprogrammed
stationsoneitherFMorAM,searchsequentially
theprogrammedstationsonFMorAMandscan
theentireFMorAMband.
4.AMANTenna
AdjusttheAMloopstickforbestAMreception.
Donotleaveitpositionedagainstthebackpanel.
Todosowillreducethesignalreception.
InnoisyAMlocations,werecommendthatan
externalshieldedloopantennabeused.A
shieldedloopantennaismadefroma lengthof
singleconductorshieldedwire;microphonecable,
coaxialcable,etc.,arrangedina singleturnloop.
Forbestreception,orienttheloopvertically.It
maybeattachedaroundtheframeofa window
behinda curtain,onthebackoftheequipment
cabinet,orinsomesimilarway.Signalstrengthis
proportionaltothesizeoftheloop;thelargerthe
loop,thegreaterthereceivedsignal.
Topreparetheantennafromtheshielded
cable,strip¾ ofaninchofouterinsulationfrom
eachofthecableends.Fromoneend,completely
removetheexposed¾"ofshielding.Then
remove3/8ofaninchofinsulationfromthe
centerconductor.
Inserttheexposedcenterconductorintothe
AMANTpushconnector.Makesurethecutoff
shielddoesnotcomeincontactwithanything.
Ontheotherend,leavetheshieldintactand
strip% ofaninchofinsulationfromthecenter
conductor.Onthisendonly,twisttheexposed
centerconductorandtheshieldtogether.
Insertthetwistedshieldandcenterconductor
intotheground(GND)pushconnector.
5.FMANTenna
Theantennainputimpedanceis75ohms
designedtobefedbycoaxialantennacable.The
inputconnectorisa "TypeF"whichmateswith
cablecompanyfeedlinesandcoaxialcable.
Interferencerejectionandlowsignallossare
amongthebenefitsofcoaxialcable.
AnyoneoffourdifferentFMantennasystems
canbeusedwithyourMR7083.1)anoutdoorFM
antenna,2)anall-channel(UHF-VHF-FM)antenna,
3)a cableinputfromyourlocalcablecompany,
or4)theindoordipolesupplied.
A75-ohmoutdoorantennadesignedforFM
receptionisrecommendedforoptimum
performanceinallareas.Infringeareas,best
6HOWTOCONNECT

resultswillbeobtainedwitha highlydirectional
FMantennausedwitha rotator.Adjusttheposi-
tionoftheantennauntilthebestreceptionis
obtained.
A75-ohmmatcheddipoleantennasupplied
withyourMR7083maybeusedinurbanorin
highsignalstrengthareas.Theflexibilityofthe
thinwireassemblypermitsittobeplacedunder
arug,tackedbehindthestereo,orplacedinany
otherconvenientlocation.Insomecases,itmay
benecessarytopositiontheantennaforbest
signalreception.Avoidlocatingthisantennanext
tootherwiresormetalobjects.Anindoor
antennamaynotproveeffectiveinhouseshaving
metalsidingormetalinsulation.
Althougha 75-ohmcoaxialfeedlineoffersthe
bestnoiseandmultipathrejection,many
antennasuse300-ohmtwinlead.Inthiscase,use
amatchingtransformer(balum)toconverta
300-ohmantennatothe75-ohminputimpedance
ofthetuner.
6.SCOPEOUTPUT
TheHorizontaloutputistheFMdetector
outputandprovidesfrequencydeviationoutput
forFMreception.TheVericaloutputisfrom
amplitudedetectorsandprovidessignalstrength
outputforbothFMandAM.Anoscilloscopemay
beconnectedforviewingFMmultipath,signal
strength,andotherwaveforms.
7.ACPOWER
PlugtheACpowercordintoa 120volt50/60Hz
walloutlet.Theplugbladesarepolarizedsobe
certaintheplugisfullyinsertedintheoutletto
preventbladeexposure.
CAUTION:TOPREVENTELECTRICSHOCK,DO
NOTUSETHE(POLARIZED)PLUGONTHISUNIT
WITHANEXTENSIONCORD,RECEPTACLE,OR
OTHEROUTLETUNLESSTHEBLADESCANBE
FULLYINSERTEDTOPREVENTBLADEEXPOSURE.
HOWTOCONNECT7

AMLOOPANTENNA
TOAC
POWERSOURCE
HIGHSENSITIVITY
AMLOOPSTICKANTENNA
VARIABLE
OUTPUT
ADJUSTMENT
TOMclNTOSH
INFRAREDREMOTE
CONTROLEQUIPMENT
OSCILLOSCOPE
ALTERNATECONNECTION
TOFIXEDLEVELOUTPUT
MclNTOSH
PREAMPLIFIER
8CONNECTINGDIAGRAM
75FM
ANTENNA

Foldoutthephotographsontheinsideoftheback
cover. They will assist youin connecting theMR 7083
toyoursystem.Thenumbersonthephotographsrefer
totheparagraphsthatfollow.
BeforeoperatingyourMR7083AM/FMTuner,
familiarizeyourselfwiththecontrolsandwhatthey
do.Thelowerhalfofthefrontpanelistheoperating
controlcenter.Thefieldof6 touchbuttonsprovides
controlofACpower,AMorFM,andaudio
processingforstereo,mono,orspatialoperation.
The8 touchbuttonfieldcontrolsthe8 AMand8 FM
presetstations.Theremaining4 touchbuttons
providesearch,enter,andscanupanddown.The
knobisthemanualtuningcontrol.
Theupperhalfofthefrontpanelisthedisplay
area.Itshowstheoperatingstatus,digitallydisplays
thestationfrequencyandindicatesprecisetuningas
wellasstationsignalstrength.
A.SIGNAL(STRENGTH)INDICATOR
TheSIGNALindicatorisattherightofthe
stationdisplayarea.Thehorizontalrowofnine
LEDbarindicators,showstherelativestrengthof
anFMorAMstationbeingreceived.Thegreater
thenumberofbarsilluminated,thegreaterthe
receivedstation'ssignalstrength.
B.TUNINGINDICATOR
ThreeLEDs, twohorizontalarrowsand
acenterdot,locatedabovetheSIGNALindicator,
makeuptheTUNINGindicator.A stationis
preciselycenterchanneltunedwhenthecenter
dotLED,only,illuminates.
AllFMstereobroadcastswillcausetheFMMPX
barindicatortoilluminate.Itislocatedtotheleft
oftheSIGNALandTUNINGindicators.
C.STATIONFREQUENCYDISPLAY
The¾"highLEDdigitaldisplayofstationfre-
quencyonbothFMandAMprovidesa high
degreeofaccuracyandiseasytoread.The
MR7083tunesanddisplaysallFMfrequencies
88.0to108.0MHzandallAMfrequencies520to
1710kHz.
D.POWERON
TheredtouchbuttonturnstheACpoweronor
off.Whenthepoweristurnedonallindicators
illuminateandthetunerreturnstothelasttuned
stationwhichhasbeenretainedinthetuner's
electronicmemory.
E.MONO
TheMONOtouchbuttonswitchestheaudio
outputofthetunertoMONOandlightsthe
MONOindicatorinthedisplayarea.WheninFM
andtunedtoa stereobroadcast,theprogramwill
beheardasmonoandtheFMMPXindicatorwill
be off.
F.SPATIAL
TheSPATIALtouchbuttonconnectsa Mclntosh
audioprocessorwhichinfluencesbothfrequency
distributionandphaserelationshipstoprovide
enhancedspecialsounddistribution.Youwill
hearanenhancedsoundinbothAMandFM.It
operatesinbothmonoandstereo.Whenin
SPATIALtheLEDunderthetitleilluminates.
G.STEREO
TheSTEREOtouchbuttonprovidesautomatic,
FMstationactivated,stereo/monooperationand
lightstheLEDundertheSTEREOindicatorinthe
displayarea.
H.AM
TheAMtouchbuttonswitchestotheAM
circuitsofthetuner.Thestationdisplayareawill
showtheAMstationfrequencyinkilohertz.
I.FM
TheFMtouchbuttonswitchestotheFMcircuits
ofthetuner.Thestationdisplayareawillshow
theFMstationfrequencyinmegahertz.
J.SEARCH
TheSEARCHtouchbuttoncausesthestations
heldinthememoryfortouchbuttons1 thru8 to
bepreviewedfor5 secondseach.A secondtouch
stopsSEARCH.
K.PRESETSTATIONSELECTINGTOUCHBUTTONS
Amomentarypressononeofthetouchbuttons
marked1 thru8 willrecallfromtheelectronic
memorythepresetFMorAMstationassignedto
thattouchbutton.Thecorrespondinggreen
indicatorabovethenumberedtouchbuttonwill
light.
L.ENTER
TheENTERtouchbuttonandanyoneofthe
eightmomentarytouchbuttonsisusedtoinserta
stationintotheelectronicmemory.EightFMand
eightAMstationscanbepreset.
Toentera stationinthememory,tunetothe
FRONTPANELCONTROLS9

desiredstationwitheitherthemanualtuningknob
orSCANtuning.PresstheENTERtouchbutton.Then,
within5 seconds,pressa touchbutton,1 through8,
andthestationtunedwillberecordedintheelec-
tronicmemory.
Thepresetmemorycircuitsaremaintainedbya
speciallonglifebatterypowersupply.Itwillretain
theinstructionsforyears.
M.SCAN
UsetheSCANtouchbuttonstoautomatically
tunetothenextstationeitherupordownthe
selectedbroadcastband.Thearrowbesidethe
touchbuttonindicatesthedirectionofscan.
N.TUNINGKNOB
Rotatethetuningknobuntilthecorrect
frequencyshowsinthedisplayarea.Manual
tuningisautomaticwhenyouturnthetuning
knob.
Astationiscorrectlytunedwhenonlythe
centerdotoftheTUNINGdisplaylights.Oneach
sideofthecenterdotarehorizontallydisplay
() arrows.Oneofthesewilllightasa station
isapproachedtoindicatetuningaboveorbelow
thecenterfrequencyoftheFMstation.OnAM,
theTUNINGdisplayarrowsarenotlighted.
10FRONTPANELCONTROLS

PERFORMANCEGUARANTEE
PerformanceLimitsarethemaximumdeviation
fromperfectionpermittedfora Mclntoshinstrument.
WepromiseyouthatyourMR7083mustbecapable
ofperformanceatorexceedingtheselimitsoryou
getyourmoneyback.Mclntoshistheonlymanufac-
turerthatmakesthisguarantee.
FMSECTION
USABLESENSITIVITY
11.25dBFwhichis1.0µVacross75ohms
50dBQUIETINGSENSITIVITY
Mono—15dBFwhichis1.6µVacross75ohms
Stereo—37dBFwhichis20µVacross75ohms
SIGNALTONOISERATIO
Mono—80dB
Stereo-75dB
FREQUENCYRESPONSE
Mono—+0,-1dBfrom20to15,000Hz
Stereo-+0,- 1dBfrom20to15,000Hz
HARMONICDISTORTION
Mono- 0.08% at 100Hz
0.08%at1000Hz
0.12%at10,000Hz
Stereo-0.08%at100Hz
0.08%at1000Hz
0.12%at10,000Hz*
INTERMODULATIONDISTORTION
Mono-0.08%
Stereo—0,12%
CAPTURERATIO
1.5dB
ALTERNATECHANNELSELECTIVITY
70dB
SPURIOUSRESPONSE
100dB
IMAGERESPONSE
80dB
STEREOSEPARATION
50dB
AMSECTION
SENSITIVITY
AM20µVexternalantennainput
(50ohmsourceinput)
SIGNALTONOISERATIO
50dBat30%modulation
60dBat100%modulation
HARMONICDISTORTION
0.5%maximumat30%modulation
FREQUENCYRESPONSE
50Hzto6000HzNRSC**
ADJACENTCHANNELSELECTIVITY
45dBminimumIHF
IMAGEREJECTION
78dBminimum
GENERALINFORMATION
AUDIOOUTPUT
Fixed:1.2VRMSat100%modulation
Variable:1.2mVto1.2Vat100%modulation
SEMICONDUCTORCOMPLEMENT
Transistors37
IntegratedCircuits28
Varactors8
LEDs53
Diodes74
POWERREQUIREMENT
120V50/60Hz10watts
MECHANICALINFORMATION
SIZE:
16-1/8incheswide(40.6cm)by5-7/16incheshigh
(13.8cm)by13inchesdeep(33cm),fromthe
mountingsurface,includingPANLOCshelfand
backpanelconnectors.Knobclearancerequiredis
1-1/4inches(3.2cm)infrontofthemountingpanel.
FINISH:
Frontpanelisglasswithspecialgold/tealnomen-
clatureilluminationandblackwithgoldanodized
aluminum.Chassisisblack.
MOUNTING:
ExclusiveMclntoshdevelopedprofessional
PANLOC
WEIGHT:
15½pounds(7.0kg)net,27½pounds(12.5kg)in
shippingcarton
*Spectrumanalyzerrequiredformeasurement
**NationalRadioSystemsCommitteeproposedspec,
forAMtuners,Dec.'89
PERFORMANCELIMITS11

FMPerformanceat98MHz
1kHzModulation
0102030405060708090100
AMPerformanceat1MHz
400Hz30%Modulation
-100 -90-80-70-60-50-40-30-20
FIELDSTRENGTHINdBV/M
FMFrequencyResponse
andStereoSeparation
FREQUENCYINHz
001k10k
FMSelectivity
10
0
-10
-20
-30
-40
-50
-60
-70
-80
•600-400-2000 200400600
AMSelectivity
10
0
-10
-20
-30
-40
-50
•60
-15-10-50 5 1015
FREQUENCYINkHz
12PERFORMANCECHARTS
RESPONSE
INdB
FREQUENCYINHz
1001k10k
20k 20
10
0
-10
-20
-30
-40
-50
-60
-70
AUDIO
OUTPUT
INdB
INPUTLEVELINdBf
10
0
-1 0
-20
-30
-40
-50
-60
-70
AUDIOOUTPUT
INdB
10
0
-10
-20
-30
-40
-50
-60
-70
AUDIO
OUTPUT
INdB
AMFrequencyResponse
NRSCRESPONSE
10
0
-10
-20
-30
-40
-50
AUDIOOUTPUT
INdB
NON-NRSCRESPONSE
20
20k
RESPONSE
INdB
NOISE
NOISEPLUSDISTORTION
OUTPUT
EITHERMONOORSTEREOOUTPUT
STEREONOISEPLUSDISTORTION
MONONOISEPLUSDISTORTION
NOISE
RESPONSE
SEPARATION
FREQUENCYINkHz

TUNINGSYSTEM
TheMR7083hasthreemodesoftuning,MANUAL,
SCAN,andPRESET.
IntheMANUALmode,twophotoelectricsensors
sensethedirectionanddegreethatthetuningknob
isrotatedandmovethetunedfrequency
accordingly.Thesmoothnessandeaseoftuning
providedbythissystemisa resultofonlylight
comingincontactwithsmallmetalveinsattachedto
thetuningshaft.Therefore,frictionisalmost
non-existentandflywheelactionissuperior.
Whena SCANpushbuttonispressed,a ramped
tuningvoltageisgenerated,increasinginvoltagefor
SCANup,decayingforSCANdown.Theramp
continuesuntilthezerocrossingofthedetector'sS
curveissensedattheinputofthecontroller.Itthen
stopsandmaintainsthatvoltagewithanynecessary
correctionadded.
Oncea stationhasbeentunedbyeitherthe
MANUAL or SCANmode , youmay ENTER it into
anyoftheeightmemorylocations.Simplypress
ENTER, then within 5 seconds,press the desired
STATIONbutton,1 through8.Thestationisthen
storedinthetuningcontroller'smemory.
Amomentarypressofa presetSTATION
pushbuttonwillinstantaneouslyrecallthestation
frommemory.A lithiumbatterymaintainsthe
memoryformorethan10years.Eachtimea
pushbuttonispressed,a mutepulsesuppressesany
noisethatmightoccurduringthetuningprocess.
Duringthescanmode,anoutputfromthecontroller
lowersthetunersensitivity.Thispreventsweaknoisy
stationsfrombeingcaptured.Ifonewishestolisten
toweakstations,theymaytunethemmanually.
FMTUNER
AtypeF connectorisprovidedontherearpanel
forconnectionofa 75ohmantennaorcablesystem.
FollowingtheantennamatchingcircuitisanRF
tunerofexceptionalperformance.Itusesa
DMOSFETRFamplifier,DoubleBalancedMixerand
4RFcircuitsthataretunedbymatchedvaractor
diodes.Theresultsarehighspuriousrejectionand
greatsensitivity.Thiscircuitryandhightuning
voltageeliminateRFintermodulationdistortion
causedbydiodenonlinearities.
TheFMIFsectionuses2 transistors,3 linearphase
piezoelectricfilters,and2 integratedcircuits.They
combinetoprovideover120dBofgainanda
selectivitygreaterthan70dB.Limiting,muting,signal
strengthdrive,andFMdetectionareallfunctionsof
thelastIFintegratedcircuit.
Aphaselockedloop(PLL)stereodecoder
integratedcircuitistheheartofthemultiplex
section.Ithasa highsignal-to-noiseratio,low
distortion,highchannelseparation,andhighSCA
rejection.ThePLLMPX1Celiminatesinductorsto
minimizedrift,providesintegrallampdriving
capabilityforstereoindication,andhastransientfree
mono/stereoswitching.
FollowingthePLLMPXdecoder,anLCtuneddual
notchfilter(19and38kHz)isusedtopreventtape
recorderbiasinterference.TheLCfilterisdriven
fromtheMPXoutputamplifierandisterminatedby
anoperationalamplifier.Thisprovidesthenecessary
filterinputandoutputimpedancesforproperphase
response.
AMTUNER
Thefirstelementintheinputsectionisa newLow
ImpedanceLoopstickAntenna.ItreceivesalltheAM
stationsandrejectsnoiseandotherinterference.A
JFET-Transistorcascodeamplifierfollows.This
amplifierprovidesexcellentsensitivityandspurious
responserejection.Italsohasa delayedAGCsystem
thatenhancestheoverloadperformancemargin.
Twovaractortunedcircuitsanda doublebalanced
mixerarenext.Thistypeofmixerhasexcellent
imageandIFrejection.
Themixer's450kHzoutputfeedsa matching
transformerforthewidebandlinearphase
piezoelectric4 elementlatticefilter,thentheIF
amplifier,anothertransformer,andfinallytheAM
detectors,filterandmutingcircuits.
Pushterminalsareprovidedforusewithan
externalAMantenna.Duetotheunusualdesignof
theAMRFinputsection,almostanytypeofantenna
canbeused.
AUDIOPROCESSOR
TheMR7083containsanaudioprocessorthat
looksatL + R andL - R informationand
ENHANCESthesoundbymodifyingthefrequency
andphaseresponse.
IfthetunerisintheMONOmode,andtunedto
anAMora weakFMstation,itprovidesa stereo
effect.Sincethisisdoneataudiofrequencies,it
doesnotdegradethesignal-to-noiseratio.When
receivinga strongFMstationinstereo,itENHANCES
apparentseparationgivinga widerstereoimage.
TECHNICALDESCRIPTION13

ANTENNAINPUTS
FM
TheMR7083isprovidedwitha 75ohmcoaxial
antennainput.Itisa standard"F"connectorthat
mateswithmostcommonantennaandcableservice
feedlines.Thistypeofinputcombineslowlosswith
interferencerejectingshielding.
Amatcheddipoleantennaisprovidedforaverage
reception.However,optimumperformanceis
obtainedwithanoutdoorhighlydirectionalbeam
antennaandrotator.
Althougha 75ohmcoaxialfeedlineoffersthebest
noiseandmultipathrejection,manyantennasuse
300ohmtwinlead.Ifthisisthecase,a matching
transformer(balum)canbeused.
AM
TheAMantennainputontheMR7083isunusual
inthatitwillacceptalmostanytypeofantenna.Ina
locationofmoderatesignalstrengthandlittle
interference(fewfluorescentlights,motors,TVsets,
etc.),thenewLowImpedanceLoopstickwillgive
goodperformance.Ina ruralarea,anoutdoor
long-wiremightbedesirable.However,thebest
over-allperformanceina weaksignalareacanbe
obtainedbyusinga shieldedloopantenna.
Theshieldedloopisa bi-directionalantenna.Its
maximumsignalpickupoccurswhenthestationlies
inthesameplaneastheloop.Minimumsignalis
perpendiculartotheloop.Thischaracteristiccanbe
usedtoadvantagebyarrangingtheloopsothatan
unwantedsignal,noiseorinterferingstation,isin
thepickupnull.
REMOTECONTROL
A15pinsubminiatureD connectorisprovidedon
therearpanelforinterfacingtheMR7083with
MclntoshIRremotecontrolsystems.
14TECHNICALDESCRIPTION

MR
7083
BLOCKDIAGRAM15

THELOCATIONOF
CONTROLS
Thenumbersandletterscorrespondtotheparagraphsonpages6,7,9 and10