ModelMRMIOIMusicRecoveryModule
Introduction
TheMusicRecoveryModule(referredtoasMRM)isdesigned
toremovetheobjectionablenoisesheardwhenaphono
pickupmeets
a
scratchontherecordbeingplayed.
TheMRMisnotintendedtoremoveallnoisesassociatedwith
old,
wornorgenerallydirtyrecords.Sincethesenoisesoccur
inanalmostcontinuousmanner,theirdetectioncouldleadto
theremovalof
a
substantialproportionoftheoriginal
recording.
TheMRMcontains
a
highqualitystereopre-amplifierwith
magneticphonoinputs.ThisallowstheMRMtobesimplyand
directlyconnectedtotheamplifier'auxiliary'or'tuner'inputs.
Thescratchdetectioncircuitrecognisesthewholewaveformof
thescratchanddistinguishesitfromthepeaksoftherecorded
music.Inordertoallowthescratchdetectioncircuitsufficient
timetomakethedecisiontoremovethescratch,thechannels
areindividuallydelayedby
a
fewmiUi-secondswithoutlimiting
theaudiofrequencyrange.
Afterrecognisingthescratch,aspeciallydesignednetwork
isolatesthesignalforsufficienttimeforthescratchnoiseto
passoutofthedelayline.
Patentsappliedfor.
WARNING:Topreventfireorshockhazard,donotexposethis
appliancetorainormoisture.
Specifications
Input
Suitableforpickupcartridgeshavinganoutputof0.7to
2mV7cm/sec.
Inputimpedance
47kohm.
Frequencyresponse
±1.5dB
2OH2
to20kHz(includingequalisationnetworkfor
magneticcartridges).
Dynamicrange
Directmode:greaterthan100dB.
Viasuppressor:greaterthan80dB(typically85dB).
(Unweighted20Hzto20kHzref.to1kHzmaximumoutput.)
Distortion
At1kHzatnominaloutput:
Directmode:Typicallylessthan
0.01
%
T.H.D.
Viasuppressor:Typicallylessthan
0.1
%
T.H.D.
Channelbalance
Betterthan2dBat1kHz.
Nominaloutput
300mVRMS.
Output
For
1%
T.H.D.at1kHz:
Suppressor'in'2.5Vrms.
Suppressor'out'8Vrms.
Outputimpedance
3.3kohm.
Ratedloadimpedance
Greaterthan10kohm(shortcircuitprotected).
Powersupply
120V
AC,
50/60HZ7VA,or220/240V,AC50/60Hz7VA.
Dimensions
378mmx 298mmx 71mm(Wx D x H).
Shippingweight
3.7kg
(8.161b).
Garrard'spolicyisoneofcontinueddevelopmentand
thereforetheCompanyreservestherighttoalterspecifications
withoutnotice.
ForServiceandEnquiries:
GarrardEngineeringLimited,
SalesServiceDepartment,
KembreyStreet,
Swindon,
WiltshireSN26BP.
Telephone:Swindon(0793)41701
Or,in
U.S.A.:
PlesseyConsumerProducts,
GarrardDealerSalesDivision,
100CommercialStreet,
Plainview,NewYork11803.
Telephone:(516)938-8900
Connections
Connectingtothepowersupply
Thepowersupplyleadentersattherighthandsideoftherear
panel.
Important: Beforeconnectingtothepowersupplyensureby
thevoltageinstructionlabelonthebackpanelthattheMRMis
suitableforthesupplyvoltage.
1.
UnitedKingdomonly.A powersupplyplugisnotfittedand
asthecoloursofthewiresinthemainsleadof
the
MRM
maynotcorrespondtothecoloursidentifyingtheterminals
inyourpowersupplyplugproceed
as
follows:
TheBROWNwiremustbeconnectedtotheterminalinthe
plugmarkedV orcolouredred.
TheBLUEwiremustbeconnectedtotheterminalinthe
plugmarked'N'orcolouredblack.
Aseparateearthwireisnotrequired.
If
a
13amp(BS1363)plugis
used,
fit
a
3 ampor
5
ampfuse.
Foranyothertypeofplugprotectwitha5ampfuseorfuse
wireintheadaptorordistributorboard.
2.
Europeand
U.S.A.
A suitable
2
pinplugisprovidedfor
connectiontothepowersupply.
Connectionsattherearpanel
ConnectionsattherearpaneloftheMRMarebothRCAand
DINtypeinputandRCAtypeoutputsocketstoprovidethe
facilitytolinkuptoanyequipmentlikelytobeusedwithit.
Europeanversionsalsohave
a
DINtypeoutputsocket.
TheRCAconnectorsareidentifiedL (left)and
R
(right),sothat
asignalintothe
R
connectorappearsafterprocessingonthe
R
outputconnector.
Forconvenience,thepickupinputandtheamplifieroutput
connectionsareplacedateithersideofthesignalearth( -t )
terminalrespectively.
Itmaybefoundadvantageoustoconnect
a
leadbetweenthe
amplifierorrecordplayer
and
theMRMsignalearthterminals,
tominimisehum.
Audioconnectingleads(U.K.andEurope)
TheMRMissuppliedwithanaudioconnectingleadspecially
wiredwitha
5-pin
DINtypeplugatoneendand
RCA
type
J
