McIntosh MQ 101 User manual

THEMclNTOSHMQ101ENVIRONMENTALEQUALIZER
Price$1.25

YourMQ101Environmental
Equalizerwillgiveyoumanyyears
ofpleasantandsatisfactory
performance.Ifyouhaveany
questionsconcerningtheoperation
ormaintenanceofthisinstrument,
pleasecontact:
CUSTOMERSERVICE
MclntoshLaboratoryInc.
2ChambersStreet
Binghamton,NewYork13903
Phone:[phone]
TakeAdvantageof3 years
ofFREEFactoryService...
FillIntheApplicationNOW.
MclntoshLaboratoryIncorporatedguaranteesthis
instrumenttobecapableofperformanceasadver-
tised.Wealsoguaranteethemechanicalandelec-
tricalworkmanshipandcomponentstobefreeof
defectsfora periodof90daysfromdateofpur-
chase.Ifsuchdefectsoccur,MclntoshLaboratory
oroneofitsauthorizedagencieswillrepairthe
defectatnocosttothepurchaser.Thisguarantee
doesnotextendtocomponentsdamagedbyim-
properusenordoesitextendtotransportationtoand
fromthefactoryorserviceagency.Thisguarantee
coverstheMQ101only,andnotitscabinet.
THREEYEARFACTORYSERVICECONTRACT
Anapplicationfora FREETHREEYEARFACTORY
SERVICECONTRACTisincludedwiththismanual.
Thetermsofthecontractare:
ForThreeYearsfromdateofpurchase—
1.Mclntoshwillprovideallparts,materialsand
laborneededtoreturnthemeasuredperformance
oftheinstrumenttotheoriginalperformance
limitsfreeofany charge.TheSERVICECON-
TRACTdoesnotcoverany shippingcoststoand
fromtheauthorizedserviceagencyorthefactory.
2.AnyMclntoshauthorizedserviceagencywillre-
pairallMclntoshinstrumentsatnormalservice
rates.Toreceivethefreeserviceundertheterms
oftheSERVICECONTRACT,theSERVICECON-
TRACTCERTIFICATEmustaccompanytheinstru-
mentwhentakentotheserviceagency.
3.Alwayshaveservicedonebya Mclntoshauthor-
izedserviceagency.Iftheinstrumentismodified
ordamaged,asa resultofunauthorizedrepairthe
SERVICECONTRACTwillbecancelled.Damage
byimproperuseormishandlingisnotcoveredby
theSERVICECONTRACT.
4.TheSERVICECONTRACTisissuedtoyouasthe
originalpurchaser.Toprotectyoufrommisrepre-
sentationthiscontractcannotbetransferredtoa
secondowner.
5.TheSERVICECONTRACTisgiventopurchasers
wholiveinthe50UnitedStatesorCanadaonly.
6.ForyourprotectionMclntoshselectsItsdealers
carefully.Onlyonedealerintenqualifiesfora
Mclntoshfranchise.ToreceivetheSERVICE
CONTRACTyourpurchasemustbemadefroma
Mclntoshfranchiseddealer.
7.YourcompletelyfilledInapplicationfora SERV-
ICECONTRACTmustbepostmarkedwithin30
daysofthedateofpurchaseoftheinstrument.
8.ToreceivetheSERVICECONTRACTallinforma-
tionontheapplicationmustbefilledin.The
SERVICECONTRACTwillbeissuedwhenthe
completelyfilledinapplicationIsreceivedat
MclntoshLaboratoryIncorporatedInBinghamton,
NewYork.Iftheapplicationisnotreceivedat
MclntoshLaboratory,onlytheserviceoffered
underthe90-dayguaranteewillapply.
Copyright© 1970byMclntoshLaboratory,Inc.
CONTENTS
GUARANTEE1
INSTALLATION2
HOWTOCONNECT3,4
USINGTHEFRONTPANELCONTROLS5
PERFORMANCELIMITS6
PERFORMANCECHARTS6
TECHNICALDESCRIPTION7,8
BLOCKDIAGRAM8
1
GUARANTEE

Installation
Adequateventilationextendsthetrouble-freelife
ofelectronicinstruments.Itisgenerallyfoundthat
each10°centigrade(18°F)riseintemperaturere-
ducesthelifeofelectricalinsulationbyonehalf.
Adequateventilationisaninexpensiveandeffective
meansofpreventinginsulationbreakdownthatre-
sultsfromunnecessarilyhighoperatingtempera-
tures.Thedirectbenefitofadequateventilationis
longer,trouble-freelife.Allowatleast15inches
deepx 16½incheswidex 3½incheshighformount-
ingtheMQ 101.
TopreparetheMQ101forinstallationremovethe
plasticprotectivecovering.Turnitupsidedownso
thatitrestsonitstopontheshippingpallet.Remove
thetwoscrewsthatfastenthechassistothecabinet.
Afterthescrewshavebeenremovedslidethechassis
outofthecabinet.Next,placethemountingbrackets,
thepartsbagandthemountingtemplateathand.
ThePANLOCprofessionalmountingdesignelimi-
natestheneedforanyshelforbracket.TheMQ101
issupportedbyitsownmountingbrackets.
Thedesignofthemountingtemplateallowsyouto
positionorlocatethecutoutfromthefrontorrearof
thepaneltowhichtheinstrumentistobemounted.
Positiontheplasticmountingtemplateoverthearea
ofthemountingpaneltobecutoutforinstallation.
Ifthecutoutistobelocatedfromthefrontofthe
panel,beginatStep2.Ifthecutoutistobelocated
fromtherearofthepanel,beginhere.
1.Onthebackofthemountingpanel,scribea ver-
ticalcenterlinethroughtheexactcenterofthe
areainwhichthecutoutistobemade.
Placethetemplateagainstthebackofthepanel
andmatchthetemplatecenterlinewiththecenter-
lineonthemountingpanel.
Makesurethatthereisatleast¼ inchclearance
betweenthebottomofthedashedlineofthecut-
outareaonthetemplateandanyshelforbrace
belowtheproposedcutout.
Markthelocatingholes("C"holesonthe
mountingtemplate).
Drillthetwolocatingholes.Becertainthedrill
isperpendiculartothepanel.
Nowpositionthetemplateonthefrontofthe
panelbyaligningthe"C"locatingholesonthe
templatewiththedrillholes.
2.Ifthecutoutistobelocatedfromthefrontofthe
mountingpanel:
Withthetemplateinplaceagainstthefrontof
themountingpanel,markthe"A"and"B"drill
holesandthefoursmallholesthatidentifythe
cornersofthecutout.Jointhecornermarkswith
aline.Theedgeofthetemplatecanbeusedasa
straightedge.
Accuratelydrilltheholesoneachsideofthe
cutoutareawitha3/16inchdrill.
IMPORTANT:DRILLTHE6 HOLESBEFORE
MAKINGTHECUTOUT
Carefullycutouttherectangularopening.Becer-
taintosawontheINSIDEofthelines.
Securethemountingstripstotherearofthe
mountingpanelusingtwoscrewsfromthehardware
package.Insertthescrewsinthecenterholesofthe
cabinetpanel("B"holesonthetemplate)and
tighten.Thescrewheadshouldpullintothewood
slightly.(Usetwo¾ inchlongscrewsformounting
panelsupto½ inchthick,ortwo1¼inchlongscrews
forpanels½ inchthickandover.)
Attachthemountingbracketstothemounting
panelusingfourscrews.
Placethetemplateoverthemountingscrews.The
mountingscrewsshouldbecenteredinthe"A"and
"B"holesonthetemplate.Thesidesofthemount-
ingbracketsshouldmatchtheverticaldashlineson
thetemplate.Ifnecessary,loosenthescrewsand
pushthebracketsintoalignmentandretighten.
Insertthepowercordthroughthemountingpanel
opening.CarefullyslidetheMQ101intotheopening
sotherailsonthebottomoftheequipmentslidein
thetrackofthemountingbrackets.Slidetheinstru-
mentinuntilitsfrontpanelisagainstthemounting
panel.AtthebottomfrontcornersarethePANLOC
buttons.DepressingthePANLOCbuttonswilllock
theinstrumentfirmlyintheinstallation.Depressing
thePANLOCbuttonsa secondtime(aswitha ball-
pointpen)willreleasetheinstrument.Youcanthen
slidetheinstrumentforwardforeasyremoval.
2

CONNECTINGTOA PREAMPLIFIER/POWER
AMPLIFIERSYSTEM
TheMQ101isaddedtothecircuitbetweenthe
preamplifierandpoweramplifier.Connectshielded
cablesbetweentheMAINoutputsofthepreamplifier
andtheMAINinputsontheMQ101.Connect
shieldedcablesfromtheMAINoutputsoftheMQ101
totheinputsofthepoweramplifier.Thelengthofa
connectingcableislimitedbyitselectricalcapacit-
ance.Thetotalcapacityofeachcablemustnotbe
morethan1000pF.Forinstance:Cableswith25pF
perfootmaybe40feetlong.Theinputimpedanceof
thepoweramplifiershouldbe47,000ohmsormore.
ForbestsignaltonoiseratiowhenusingtheMQ
101betweena preamplifierandpoweramplifierthe
inputattenuatorswitchonthebackpanelofthe
MQ101shouldbeinthe0 dBposition.Whenused
withpreamplifiersthathavebasstrimcontrolsitis
recommendedthatthebasstrimcontrolsbesetin
theflatposition.
3

CONNECTINGTOA RECEIVERUSING
TAPEMONITORJACKS
Connectshieldedcablesbetweenthetapeoutputs
onthereceiverandtheMAINinputsontheMQ101.
ConnectshieldedcablesfromtheMAINoutputsof
theMQ101tothetapemonitorinputsonthere-
ceiver.Thetaperecordercanbeconnectedtothe
tapemonitorfacilitiesontheMQ101inconventional
fashion.Thelengthofa connectingcableislimited
byitselectricalcapacitance.Thetotalcapacityof
eachcablemustnotbemorethan1000pF.Forin-
stance:Cableswith25pFperfootmaybe40feet
long.Theinputimpedanceofthepoweramplifier
shouldbe47,000ohmsormore.
Theinputattenuationswitchonthebackpanelof
theMQ101shouldbeinthe—12dBpositiontopre-
ventthephonocartridgeoutputfromoverloadingthe
MQ101atlowfrequencies.
PLEASENOTE—TOUSETHEMQ101THETAPE
MONITORSWITCHONTHERECEIVERMUSTBE
LEFTINTHE"IN"POSITION.
CONNECTINGTOA RECEIVERWITH"PREAMP
OUT/POWERAMPIN"FACILITIES
Connectshieldedcablesbetweenthepreamplifier
outputjacksandtheMAINinputsontheMQ101.
ConnectshieldedcablesbetweentheMAINoutputs
ontheMQ101andthepoweramplifierinputsonthe
receiver.Whenconnectedinthisfashionmakecer-
taintheinputattenuationswitchonthebackpanelof
theMQ101isinthe0 dBposition.
ACPOWEROUTLET
TheauxiliaryACpoweroutletcanbeusedtosup-
plypowertootherequipmentinthesystem.Theout-
letisnotswitchednorisitfusedintheMQ101.
ACPOWER
TheMQ101operateson117to130volts,50/60
Hz.Itwillbeturnedonandoffwhenitspowercordis
pluggedinoneoftheswitchedauxiliaryACpower
outletsintheprogramsource.
FUSE
TheMQ101usesa 0.5Ampfuse.TheauxiliaryAC
poweroutletisnotfused.
4

UsingtheFrontPanelControls
InMclntoshloudspeakersthecharacteristicsof
thespeakerenclosureandthecharacteristicsofthe
loudspeakermechanismshavebeencombinedto
producenearlyperfecttransientresponse.Thede-
signforexcellenttransientresponsehastocom-
promisethesystemlowfrequencyresponse.The
mosteffectivemeansofrecoveringa flatlowfre-
quencycharacteristicistheuseofanelectrically
equalizedspeakerinputsignal.TheMclntoshEn-
vironmentalEqualizerdoesthisjob.Conventionally
designedloudspeakersshouldnotbeusedwiththe
MQ101sinceitwilloverdrivethem,distortingthe
soundanddecreasingtheirusefullifeexpectancy.
Mclntoshloudspeakersshouldnotbeusedwithother
equalizerssincetheyaredesignedforotherapplica-
tionsandwillnotproducethelowintermodulation
characteristicandtheproperfrequencybalance
whichissoimportant toMclntoshsound.
Whena MclntoshEnvironmentalEqualizerisprop-
erlyconnectedinthestereosystemallprogramma-
terialatalloutputsexceptthetapeoutputwillbe
equalized.
TAPEMONITOR
TheTAPEMONITORisusedonlywhentheMQ101
hasbeenconnectedtothetapemonitorfacilitiesof
thesourceequipment.Thecontrolisusedinexactly
thesamefashionasthetapemonitorcontrolonthe
sourceequipment.
LOWFREQUENCY
Afivepositionconcentricswitchselectsfromfive
differentlowfrequencyequalizationcurves,inde-
pendently,ineachchannel.Theouterknobadjusts
therightchannelresponse.Thecenterknobadjusts
theleftchannelresponse.Uselowfrequencyequali-
zationtocompensatefortheplacementoftheloud-
speakerinyourroom.Position1 modifieslowfre-
quencyresponseleastandposition5 hasthegreat-
esteffectonlowfrequencies.
MIDFREQUENCY
Afivepositionswitchselectsfromfivedifferent
midfrequencyequalizationcurvesforbothchannels.
Usemidfrequencyequalizationtocompensateforthe
effectsofroomacousticsandfurnishingsonthemid
frequencies.Positionsoneandtwoselectcurvesthat
decreasetheamountofmidrangeloudnessand
positionsfourandfiveselectcurvesthatincreasethe
amountofmid-rangeloudness.Position3 iselectri-
callyflat.
HIGHFREQUENCY
Afivepositionswitchselectsfromfivedifferent
highfrequencyequalizationcurvesforbothchan-
nels.Positionsoneandtwoselectcurvesthatde-
creasethehighfrequencyloudnessandpositions
fourandfiveselectcurvesthatincreasethehigh
frequencyloudness.Position3 iselectricallyflat.
PANLOC
MclntoshdevelopedPANLOCmountingbringspro-
fessionalinstallationtechniquetostereo.Whenthe
MQ101hasbeeninstalledonPANLOCbrackets,
pressingthePANLOCbuttonslockstheequalizer
firmlyin.Depressingthebuttons(aswitha ballpoint
pen)releasestheinstrument.Theequalizercanthen
beslidforwardforeasyremoval.
5

PerformanceLimits
PERFORMANCEGUARANTEE—PerformanceLim-
itsarethemaximumdeviationfromperfectionper-
mittedfora Mclntoshinstrument.Wepromiseyou
thattheMQ101youbuymustbecapableofperform-
anceatorexceedingtheselimitsoryougetyour
moneyback.Mclntoshistheonlymanufacturerthat
makesthisguarantee.
FREQUENCYRESPONSE:0.5dBfrom20Hzto
20,000Hz
DISTORTION:0.1%atratedoutputlevel,20Hzto
20,000Hz
HUMANDNOISE:80dBbelowratedoutput(250
µV)
INPUTSENSITIVITYANDIMPEDANCE:Mainand
tapeinput2.5voltsat60,000ohmsforratedoutput
at 1000 Hz
INPUTATTENUATOR:Switched0 dB,-6dB,or
-12dB
OUTPUT:Main:2.5voltsinto47,000ohmsormore,
20to20,000Hz
Tape:2.5voltswithratedinput
EQUALIZATION:Lowfrequency:0 to+17dBat20
Hzin5 steps(0,+6,+9,+13,+17dBinpositions
1,2,3,4,5,respectively)
Midfrequency:-5to+5dBat4000Hzin5 equal
steps
Highfrequency:-4to+4dBat20,000Hzin5 equal
steps
POWERREQUIREMENT:120volts,50/60Hz,20
watts
MECHANICALINFORMATION
SIZE:Frontpanel:16incheswide(40.64cm)by
2-15/16incheshigh(7.46cm)
Chassis:15incheswide(38.1cm)by13inches
deep(33.02cm)includingPANLOCshelfandback
panelconnectors;KnobClearance:1½inches
(3.81cm)infrontofmountingpanel
FINISH:FrontPanelAnodizedgoldandblackwith
specialgoldtealpanelnomenclatureillumination.
CHASSIS:Chromeandblack
MOUNTING:MclntoshdevelopedprofessionalPAN-
LOC
WEIGHT:15pounds(6.80kg)net,19pounds(8.62
kg)inshippingcarton
6

TechnicalDescription
DESIGNINGFORNATURALBASS
Researchprogramshaveonecommonadvantage
forthealertscientistandengineer.Thethousandsof
hoursofeffort,analysis,conjecture,andsynthesis
uncoveropportunitiestomakemeaningfulcontribu-
tions.Mostoftheseopportunitiesarediscoveredjust
wherelessermensawonlyproblems.Oneofthe
greatopportunitiesthattheMclntoshacousticsre-
searchteamuncoveredwasa designfornatural
soundofbassinstruments.
Whena bassdrumisstruck,themotionofthe
diaphragm(drumhead)pumpsa largevolumeofair.
Thereproductionofsucha soundimagerequires
themotionofthesamevolumeofairor,atleast,a
significantportionofit.Becausethedesignobjec-
tivesoflowdistortionandwidelydispersedradia-
tiondictatea maximumeffectiveconediameterof
10inchesthelowfrequencyloudspeakerhadtobe
designedwithlargeexcursion(backandforthmove-
ment)toachievetheairvolumemovementnecessary.
Ourdesignobjectivewasthedevelopmentofa low
frequencyloudspeakerwitha plusandminusone
halfinchconeexcursion.Evenwiththislargeex-
cursion,a straightlinerelationshipbetweendriving
forceandmovementhadtobemaintained.
Toachievethislinearrelationshipourengineers
employeda longvoicecoilwinding,a verylightedge
andcenteringsuspensionandanairspring.Theair
springisthenaturalresultofmountingthespeaker
ina relativelysmallairtightextremelyrigidbox.
Whentheconemovesinward,itreducesthevolume
ofairtherebyincreasingitspressure.Theincreased
airpressurereturnstheconetothecenterofits
travelwhentheelectricalsignalreturnstozerovalue.
Whentheconemovesoutward,thevolumeofairin-
creasesreducingtheairpressureinthebox.Theair
pressureintheroomcannowrestoretheconetoits
centerpositionwhentheelectricalsignalagain
reacheszero.Oneofthepropertiesofanairspring
isanalmostperfectlystraightlinerelationbetween
volumeandpressureforsuchsmallchangesinvol-
ume.Thisinsuresa lowlevelofdistortionatlow
frequenciesandalsoa lowlevelofintermodulation
distortion.
Thelinearairspringwascombinedwitha stiff
cone,a longvoicecoilwindinganda verylargeand
massivemagnetstructuretoachievealmostperfect
transientresponseforbassfrequencies.
Designengineers,inthepast,havenottakenad-
vantageofthisopportunitytoobtainexcellenttran-
sientresponsebecauseofthepricethatmustbe
paid.Thatpriceisa reductioninbassresponse.
Therearetwowaysaroundthisproblemoflossof
bass.Intheoldertechnologicalapproachtoloud-
speakersystemdesign,flatfrequencyresponsewas
obtainedbycompromisingthetransientresponse
usingmechanicalresonancesinthespeakerandits
enclosure.Thishasbeenthetraditionalsolutionwith
itsemphasisoncostreductionratherthanreproduc-
tionaccuracy.
Theothersolutionisthenewapproach.Torestore
thesystemtoa flatfrequencyresponsewhilepre-
servingnearlyperfecttransientresponse,anelec-
tricalsignalissuppliedhavinganexactlyopposite
curvetothecurveofthereductioninbassresponse.
Supplyingthiselectricalsignalintroducesan
equalizerintothissystem.Thecombinationofthe
loudspeakersystemandtheequalizerproducesboth
aflatresponseandanexcellenttransientcharacter-
istic,freeofringing,downto20Hz.
Asifthisadvantagewerenotenough,theequalizer
bringsaboutanotheradditionalimprovementtothe
system.Thepositionoftheloudspeakerintheroom
cansubstantiallyaltertheloudspeaker'ssoundbal-
ance.Theequalizercanbedesignedtocompensate
fordifferenttypesofroomsandfordifferentpositions
oftheloudspeakersintheserooms.
DESIGNINGFORDIFFERENTLISTENINGROOMS
Thepoweroutofa bassspeakeratverylowfre-
quenciesvariesoveran8 to1 range(9decibels)
dependingonwherethespeakerispositionedinthe
room.
Forexampleiftheloudspeakerenclosureissus-
pendedinthecenterofa large,soundabsorbing
room,a 20hertzsignalwillradiateequallyinalldi-
rectionsfromtheloudspeaker.Itwillberadiating
intoa sphere.
Iftheloudspeakerenclosureisthenloweredtothe
floorinthecenteroftheroomitwouldberadiating
intoa hemisphere.Thesignalstrikingthefloorwould
bereflectedupwardandthespeakerpoweroutput
willappeartodouble.
Iftheloudspeakeristhenmovedalongthefloorto
thecenterofthewallthepowerwilldoubleagain.
Theloudspeakeristhenradiatingintoonequarter
ofa sphere.
Thenbymovingtheloudspeakerintoa cornerof
theroomtheradiationisconcentratedintoone
eighthspherewithanotherapparentdoublingin
power.
7

Wehavedesignedfivecurvatureratesintheen-
vironmentalequalizer.Theyprovidetheelectrical
correctionnecessarytomakea speakersoundasit
wouldina cornerwhenit'smountedona wallorvice
versa.Forstereo,individualleftandrightcontrols
areprovidedtocorrectfordifferentpositionsofthe
speakersintheroom.
TheMQ101inadditiontothebasscorrectionalso
providescorrectionformidfrequencyandhighfre-
quencydifferencesinrooms.Someroomsarevery
heavilydrapedandfurnished.A roomofthissort
mayneedmidfrequencyandtrebleboosttomake
themusicsoundnaturallyalive.Otherroomsare
highlyreflectiveduetousingglassareas,smooth
hardwallsandconcreteortilefloors.Theopposite
correctionmayberequiredtorestorethemusicto
thenaturalconcerthallbalance.