Please read this manual before operating the unit!

TPInLB

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Table of Contents

Introduction 4

ImportantSafetyInstructions 5

1.Operation 7

2.Modifyingfactorysettings 8

3.Specifications 12

4.Appendix1,Microphonevoltageslist 13

5.GrimmAudioLimitedWaranty 15

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Introduction

ThankyouforchoosingtheGrimmAudioMP1powersupplyfortubecondensormicrophones.TheMP1iseminentlyfittobeusedwithmoderntubemicrophones,butithasbeenespeciallydesignedtoreplacethetraditional(usuallypassive)powersuppliesthatorginallycamewiththenowuniqueandverycostlytubemicrophonesfromthefiftiesandsixties.Contrarytowhatmanybelieve,theseoldpowersuppliescanbeimprovedupon,bothwithregardtostability,noiselevelandlastbutnotleastsoundquality.Andthisisnotjustbecausetheelectrolyticsintheoldsup-pliestendtodryout,andcarboncompositeresistorshaveshotupinvalueorgonenoisy:evenifthesehavebeenreplacedwithmoderngoodqualitycomponents,theclassicalsupplyisstillnomatchfortheMP1.

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Important Safety Instructions

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Please follow these precautions when using this product:

1.Readtheseinstructions.

2.Keeptheseinstructions.

3.Heedallwarnings.

4.Followallinstructions.

5.Dangerousvoltageisinsidethisapparatus.Openingisonlyallowedbyqualifiedservicepersonnel.

6.Verifylinevoltagebeforeuse.

7.Donotdefeatthesafetypurposeofthepolarizedorgrounding-typeplug.Apolarizedplughastwobladeswithonewiderthantheother.Agrounding-typeplughastwobladesandathirdgroundingprong.Thewidebladeorthethirdprongareprovidedforyoursafety.Whentheprovidedplugdoesnotfitintoyouroutlet,con-sultanelectricianforreplacementoftheobsoleteoutlet.

8.Protectthepowercordfrombeingwalkedonorpinched,particularlyatplugs,conveniencereceptables,andthepointwheretheyexitfromtheapparatus.

9.Unplugthisapparatusduringlightningstormsorwhenunusedforlongperiodsoftime.

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10.Donotusethisapparatusnearwater.

11.Donotusethisapparatusoutside.

12.Donotexposetheapparatustodrippingorsplashing.Donotplaceobjectsfilledwithliquids(flowervases,drinkcans,coffeecups,etc)ontheapparatus.

13.Cleanonlywithadry,soft,non-fluffycloth.Donotsprayanyliquidcleanerontothecabinet,asthismayleadtodangerousshocks.Donotsprayanyliquidcleanerontothefaceplate,asthismaydamagethefrontpanel.

14.Installinaccordancewiththemanufacturer’sinstructions.

15.Donotinstallnearanyheatsourcessuchasradiators,heatregisters,stoves,orotherapparatus(includingamplifiers)thatproduceheat.Avoidexposuretodirectsunlight.

16.Useonlyattachmentsoraccessoriesspecifiedbythemanufacturer.

17.Useonlywithacart,stand,bracket,ortabledesignedforusewithprofessionalaudioormusicequipment.Inanyinstallation,makesurethatinjuryordamagewillnotresultfromcablespullingontheapparatusanditsmounting.Ifacartisused,useprecautionwhenmovingthecart/apparatuscombinationtoavoidinjuryfromtip-over.

18.Thisunitrunsslightlywarmwhenoperatednormally.Operateinanormalventi-latedarea.Ifthisproductwillbeinstalledinarack,makecertainthereissufficientairmovementwithintherack.

19.Referallservicingtoqualifiedservicepersonnel.Servicingisrequiredwhentheapparatushasbeendamagedinanyway,suchaswhenthepower-supplycordorplugisdamaged,liquidhasbeenspilledorobjectshavefallenintotheapparatus,theapparatushasbeenexposedtorainormoisture,doesnotoperatenormally,orhasbeendropped.

20.WARNING: Toreducetheriskoffireorelectricshock,donotexposethisappa-ratustorainormoisture.

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1. Operation

Upondelivery,anMP1isfactorysettothetypicalsupplyvoltagesofyourmicro-phonemodel.ThismicrophonetypeisindicatedatthebackoftheMP1.Ifthemicrophonefeaturesremotecontrolofitspolarpattern,thiscanbecontrolledwiththeoptionalknobonthefrontpaneloftheMP1.Thereisamulti-pinXLRcablecon-nectorsuppliedwiththeMP1.Youwillneedtoattachthisconnectortoyourownmicrophonecable(orletyourdealerdothat).Forwiringdata,refertothe‘specifica-tions’chapterofthismanual.PleasemakesureyoudoublecheckifyousolderedtherightwiretotherightXLRpin,yourmicrophonecangetdamagedifyoufailtodoso!

Ingeneral,weadvisetofirstconnectallcablesandthenturnontheMP1.Bydoingsooneavoidspotentialdamagetotheconnectors’plating.Itisgoodtoknowthatduetocharacteristicsofour‘shuntregulator’circuitrythepeakcurrentislimited,whichwilllengthenyourmicrophones’tubelife.

TheMP1isdeliveredwithadetachablefoot.Thiscanberemovedbygentlytwist-ingthefootcounterclockwise.Withoutfeet,twoMP1’scanbeconnectedtogethertoformastereo1U19”unit.AnMP1generatessomeheat.WhenusingastereosetofMP1’sina19”rack,itisadvisedtokeeponefreerackspacebelowandabovetoprovideoptimalcooling.

Technology

TheMP1featuresaspeciallydesigneddiscreteshunthigh-voltageregulatorfedfromacurrentsourcetomaximisesuppressionfrommainsinducedanomalies.Italsooffersverylownoise(typ.-96dBVor16uV20-20.000Hzunweighted).Moreimportantly,thisshuntsupplysoundsmorenaturalthanthemorecommonlyusedmodernseriesregulators,duetotheabsenseofelectrolyticcapacitorsattheout-put.

Itwouldhavebeenquickandeasytorelyonindustrystandardvoltageregulatorsfortheheatersupply.However,inquiteafewclassicalmicstheheatervoltageisalsousedtobiasthegridoftheamplifyingtubeinthemicrophone,implicatinganopengatewayfromheatersupplytothesensitiveinputofthemic’samplifyingstage.Wethereforechosetodesignacleanandultralownoisediscretevoltageregulatorfortheheatersupplyaswell.Itfeaturesaverylowdrifttoensuretheheatervoltagealwaysremainswithinspecs.

Boththehigh-voltageandtheheatersupplieshaveanextra‘crowbar’protectioncircuitthatwillswitchonincaseoneofthesuppliesbreaksdown.Thisisanextralineofdefencetoprotectthevaluabletubeinyourmicrophone.

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2. Modifiying factory settings

YourMP1isfactorysettothesupplyvoltagesofthemicrophonespecifiedinyourorder.IncaseyouneedtoadjusttheMP1tothesupplyvoltagesofadifferentmicrophone,therearevariousinternalsettingstofacilitatethis.Wehavetowarnyouhoweverthatselectingawrongvoltagewillveryprobablyleadtodamageofthe(sometimesveryexpensive)tube.Sounlessyouareanexperiencedengineerorlikelivingdangerously,wedonotadvisetochangethefactoryvoltagesettings!InanycaseGrimmAudiocannotacceptliabilityfordamagetomicrophones.Forthosepeoplethatstillwanttochangetheinternalsettings,pleasereadthefollowingin-structionscarefully.

Inappendix1alistcanbefoundofknownmicrophonetypeswiththeirfactoryadvicedsupplyvoltages.Shouldyourmicrophonenotbelisted,pleaseconsulttheoriginalmanufacturer.PleasealsocheckthisMP1manualonGrimmAudio’sweb-site,itmighthavehadanupdateofthemicrophonelist.Threepresethighvolt-ageareavailablefromtheMP1:120,145and210V.Thesearesetinternallyusingjumpersandnotbyexternalcontrols,toavoidcostlymistakeswhileamicrophoneisconnected.Atrimpotallowssome(+/-8%)adjustmentofthesevoltages.TheHTsupplyisinherentlyshort-circuitproofasitisashuntsupply.Asanextrasafetya“crowbarcircuit”willshutdownthecurrentsourceincasetheoutputvoltageex-ceedsthenominalvaluebymorethan12%duetomalfunctioning.However,GrimmAudiocannotacceptliabilityincaseofdamagetomicrophonesshouldeventheprotectioncircuitfail.

Fortheheatervoltagetwopresetvaluesareavailable:6.0and3.9V.Thesevaluesarechoseninconjunctiontowhatisprescribedformostclassicalmicrophones.Theytooaresetbyinternaljumpers.Athirdjumperpositionenablesatrimpotandallowstheheatervoltagetobesetatanydesiredvaluebetween3.6and7.0V.Inaddition,theoutputpolaritycanbereversedassomemicsrequirenegativeheatervoltage.Noiseisverylow:typ.<-120dBV(<1uV),animprovementofatleast30dBoverindustrystandardvoltageregulators.Theoutputisshort-circuitproof,thecurrentlimitsat0.5A.Asanextrasafetyacrowbarcircuithasbeenaddedtoprotectthemicagainstunforseenfailuresshouldtheheatervoltageexceedthenominalvalueby10%(incaseofthevariableheatervoltagesettingasecondtrim-potallowstheusertosetanappropriatethreshold).However,GrimmAudiocannotacceptliabilityincaseofdamagetomicrophonesshouldeventheprotectioncircuitfail.

Check the voltages output of your MP1

HowtheMP1isset,caneasilybemeasuredfromtheoutside:abluetestsocketallowsthemeasurementoftheheatervoltage,aredsocketgivesaccestotheHTdividedbij10(forsafetyreasons);ablacksocketpovidesagroundreference.These

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are2mmsocketssomultimetertestpinsfitdirectly.Pleasecheckthesevoltagesbeforeconnectingthemicrophone.Markthattheheatervoltagewillmeasureap-proximately0.1Vhigheratthissocketthanindicatedabove.Thisisonpurposetocompensateforcablevoltageloss.

Tominimizetheriskofaccidentaldamagetomicrophonesequipedwith3.9Vtubesbypluggingtheseintoa6VMP1supply,GrimmAudiohasdecidedtodeliverits3.9VversionwithanXLR6socketandthe6VversionwithanXLR7socket.Thefactorysetvoltageisindicatedontheback.Ofcourse,ifauserchoosestochangetheinternalvoltagesettings,theXLRpincountnolongergivestherightindication!Thisisoneofthereasonswedisencouragethechangeoffactorysettings.

TheMP1featuresarotaryswitchtoallowachoiceofpolarpatternonmicrophonesequippedwithsucharemotecontrolinput.ThecorrespondingpinontheXLR6orXLR7microphoneconnectorcanbevariedbetween0Vandthe120or145HTvolt-agesorbetween0VandHT+40V,dependingontheinternaljumpersetting.Forexample:ifHTissetto120V,itcanbevariedbetween0and120Vor0and160V.(The40Vover-voltageisnotavailableatthe210Vsettingastherearenomicro-phonesthatrequirethat).

Changing the internal settings

OpeninguptheMP1andchangingitsinternalpresetsortrimmingsisbestlefttoatrainedtechnician.Whenswitchedon,therearepotentiallydangerousvoltagesashighas300Vinside.GrimmAudiocannotacceptanyresponsabilityfordamagestoeitherpersons,ortheMP1itself,ortoanymicrophoneconnectedbyunwittinglychosenvoltagesorpolarities.

BeforeopeningtheMP1,switchoffthemainspowerandremovethepowercord.Alsoremoveanyaudiocables.Wait30secondstoallowtheHTontheelectrolyt-icstoreachasafevalue(<40V).Removethe2screwsfromonesideofthecoveraswellasthe2screwoppositeofthemontheotherside.Carefullyslidethecoverbackwards,awayfromthewoodenfront.Theelectronicswillthenbecomevisible.

Anoverviewofsettingandtrimpotsofthepcbisgiveninfig.1onthenextpage.

High Tension (HT) settings

Jumpers7to10settheHT(highvoltagetothemicrophone)to120,145or210V.Thejunperontheleft-handrowsetsthevoltage,thejumperontheright-handrowsetsthecrowbarprotection.Theyshouldalwaysbechangedinpairs:bothinthe120Vposition,orbothinthe145Vposition,orbothinthe210Vposition.FailuretodosomayshuttheMP1down,orincriminatecorrectprotectionagainstover-voltage.

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Inaddition,J4mustbesettotheupperpositionwhen210VHTischosen.(Failuretodosowillstilloutput210Vbuttheshuntsupplywillnotbeabletofunctionop-timally,possiblydegradingsoundquality).

ChoosethelowerpositionforJ4ifyouwantawiderrangeof0-160Vavailableforpolarpatterncontrolinthe120VHTcase.Thiswillalsoworkforthe145VHT,resultingina0-184Vvariablevoltage,althoughnomicrophoneisknowntousthatneedsthissetting.

ThetrimpotallowssomeadjustmentoftheHToutputvoltage.Thecrowbarprotec-tionthresholdsremainfixed.Trimmingtheoutputvoltageclosetothetresholdvaluesisnotrecommendedasthisincreasestheriskofill-triggeredshutdown.ToresetacrowbaractionitsufficestoswitchoftheMP1,waitafewsecondsandswitchonagain.

Heater Voltage Settings

Thejumperssettingtheheatervoltagearelocatedtotherightinfig.1.

FirsttakealookatthetwojumpersJ2&J3intheright-handtopcorner.Theysettheheatervoltage’soutputpolarity:||ispositive.Changetheirorientationby90degrees:==isnegative.Checkwiththered(plus)probeofthemultimeterinsertedintothebluetestsocket(nomicconnectedyet!).

Fig1.VoltageadjustmentjumpersinsidetheMP1.

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Lowerinfig.1tworowsofheaders,andtwotrimpotscanbeseen.Theright-handrowsetsthevoltages,theleft-handrowchangestheaccordingcrowbarprotectionlevels.Again,thejumpersinbothrowsmustbemovedinunison,failuretodosomayshuttheMP1down,orincriminatecorrectprotectionagainstover-voltage.Bothjumpersaresettotheupperpositionif6,0Vheatervoltageisdesired.InthelowerpositiontheMP1delivers3.9Vheatervoltage;thevalueisintentionallychosenasdeviatingfromthenominal4.0VfoundinthedatasheetoftheAC701(+/-0.2Visallowed),asmanymanufacturersspecifyaslightlylowervalueforlongertubelifeorforthesubtlechangeinmicsoundreportedbysomeusers.However,iflongmiccableswiththinwiresarebeingused,thevoltageatthemicendofthecablemaybelowerthandesired,soiftheexactvalueisconsideredcriticaltheactualresult-ingvalueshouldbemeasuredatthemicrophoneitself.Normaltubemicrophonecablesof10metertypicallyshowa0.1Vlossatthemicrophone.Atthefactory,thevoltagesarethereforesettoslightlyabove6.1and4.0Vrespectively,whichcanbemeasuredatthemultimetersocketsonthebackoftheunit.

Withthejumpersinthemidpositionbothtrimpotsbecomeactive.Thisallowstosetanydesiredheatervoltagebetween3.6and7.0V.Onecanusethisfortubemi-crophoneswithunusualheatervoltagerequirements,orincaseofverylongcablestoadjusttheheatervoltageatthemicrophonetoanexactvalue(e.g.5.8Vor3.8V).Thebestprocedureisasfollows.Firstdisconnectthemiccable.DecidewhatthevoltageVxshouldbewhichwouldsetoffthecrowbarprotection(asarule10%higherthanthedesiredworkingvoltage).Turntheprotectiontrim(left-handone)totallyanti-clockwiseuntilsoftclicksareheard.SwitchtheMP1on(nomicconnect-ed!).Adjusttheright-handtrimuntilVx+10%isreachedatthebluetestsocket;anti-clockwisewillincreasethevoltage.Nowslowlyturntheprotectiontrimclock-wiseuntilthecrowbarstepsin:aredledwillglow.Backtothevoltagetrim(R-H)again:do10clockwisehalf-turns(5fullrotations)tolowerthesettingofVout.Re-settheMP1byswitchingitoff,andafterafewsecondsonagain.NowtrimVouttothewantedVx(doNOTtouchtheprotectiontrimanymore)andmakesureyouhavesettherightHTaswell.SwitchtheMP1offagain,connectthemicrophone,switchon.Ifdesiredmeasuretheheatervoltageatthemicrophoneandmakefurthersmalladustmentsifnecessary.Thismakessenseforinstanceifoneuseslongercablesorcableswithoutathickerheaterwiring.Theheatervoltagecanbeadjustedtoanexacttargetvaluebymeasuringthevoltageinthetubemicrophoneitself.Needlesstosaythisadjustmentisbetterlefttoatrainedtechnician.

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3. Specifications

HighTensionvoltage:adjustable120/145/210V,with8%trim.VariableHighTensionvoltageforremotepolarpatterncontrol:HT+0V/HT+40V.Heatervoltage:adjustable6.0/3.9/3.6-7V

Voltagesfactorypresetformicrophonetype,indicatedontheback.4Vheatersup-plyMP1’sarefactoryshippedwitha6pinXLR,6VheatersupplyMP1’sarefactoryshippedwitha7pinXLR.

Maximumambienttemperatureforoperation:40°C.Lifeexpectancypowersupplyelectrolytics>45.000hours.Powersupplyvoltagerange+6%/-10%

Fuses:120V(USA): fuse500mA-T100V(Japan):fuse500mA-T230V(EU): fuse250mA-T

Weight:2.3kgDimensions:215x175x44mmPowerconsumption:20WWoodtypeoffront:Cherry

XLRpinning(ofboth6and7pinXLR’s):

Pin1:GNDPin2:Audio+Pin3:Audio–Pin4:HeaterPin5:HighTensionPin6:VariableHT(forremotepolarpatterncontrol)

TheXLRaudiooutputisinternallyhardwiredtothecorrespondingpinsofthemulti-pinXLR.

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4. Appendix 1, Microphone voltages list

AKGC12,C12VR:120V&6.3V,HT-var+0VpositionC24:120V&6.3V,HT-var+0Vposition(thismicrophoneisstereoandneedstwopowersuppliesandacablesplitter).(Telefunken)ElaM250,ElaM251,USversion:120V&6.3V(Telefunken)ElaM250,ElaM251,EUversion:120V&3.9VC12a:120V&5.2V,HT-var+0VpositionC28A,C29A,C30A,C60/CK28,C60/CK26:120V&3.9V:theMP1cannotbeusedwiththesemicrophonesbecausetheiroutputtransformerismountedinthesupply.

MicrotechGefellCMV563:120V&6VUM57:120V&6V,HT-var+0VpositionUM92,UM75:120V&5.8V,HT-var+40VpositionM990:120V&5.8V

Neumann(Telefunken)KM(2)53,KM(2)54,KM(2)56,KM(2)64,KM(2)66,M50,M250:120V&3.9VM49,M249,M269:120V&3.9V,HT-var+0VpositionU67:210V&5.8VSM69,SM23:120V&3.9V,HT-var+0Vposition(thesemicrophonesarestereoandneedtwopowersuppliesandacablesplitter).U47,U48:thefilamentsupplyofthesemicrophonesisderivedfromtheHTsupply.PleasebuyourMP47insteadoftheMP1,becauseitisespeciallydesignedforthis.M147,M149,M150:thesemicrophonesarepartlysolidstate.Theyneed+and-70Vand32VandcannotbeusedwithanMP1.

Schoeps(Telefunken/Philips/Siemensequivalent)CV60,CM61:145V&-5.7VM200,M201:150V&-6.3VM221b:120V&3.9VM222:theMP1cannotbeusedwiththismicrophonebecausetheoutputcircuitryismountedinitspowersupply.

SonyC37A:theMP1cannotbeusedwiththismicrophonebecausetheoutputtransform-erismountedinitspowersupply.C800,C800G:Thesemicrophonesneed276VwhichtheMP1cannotdeliver.TheC800Galsoneedsanadditional6VforthePeltierelement.

Forpowersupplyvoltageinformationofother(contemporary)tubemicrophones,pleaseconsulttheoriginalmanufacturer.TheMP1willmostlikelysupportthem.

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Grimm Audio contact information

GrimmAudioCVStrijpsestraat945616GSEindhovenTheNetherlands+31(0)402131562Email:info@grimmaudio.comWebsite:http://www.grimmaudio.com

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5. Grimm Audio Limited Warranty

GrimmAudioCV(“GrimmAudio”)warrantsthisproducttobefreeofdefectsinma-terialandworkmanshipforaperiodofone(1)yearforpartsandforaperiodofone(1)yearforlaborfromthedateoforiginalpurchase.Thiswarrantyisenforcableonlybytheoriginalretailpurchaserandcannotbetransferredorassigned.

DuringthewarrantyperiodGrimmAudioshall,atitssoleandabsoluteoption,eitherrepairorreplacefreeofchargeanyproductthatprovestobedefectiveoninspectionbyGrimmAudiooritsauthorizedservicerepresentative.Inallcasesdisputesconcerningthiswarrantyshallberesolvedasprescribedbylaw.Toobtainwarrantyservice,thepurchasermustfirstcallorwriteGrimmAudioattheaddressandtelephonenumberprintedbelowtoobtaininstructionswheretosendtheunitforservice.Allenquiriesmustbeaccompaniedbyadescriptionoftheproblem.AllauthorizedreturnsmustbesenttoGrimmAudiooranauthorizedGrimmAudiorepairfacilitypostageprepaid,insuredandproperlypackaged.Proofofpurchasemustbepresentedintheformofabillofsaleorsomeotherpositiveproofthattheproductiswithinthewarrantyperiod.GrimmAudioreservestherighttoupdateanyunitreturnedforrepair.GrimmAudioreservestherighttochangeorimprovedesignoftheproductatanytimewithoutpriornotice.

Thiswarrantydoesnotcoverclaimsfordamageduetoabuse,neglect,alterationorattemptedrepairbyunauthorizedpersonnel,andislimitedtofailuresarisingdur-ingnormalusethatareduetodefectsinmaterialorworkmanshipintheproduct.

InnoeventwillGrimmAudiobeliableforincidental,consequential,indirectorotherdamagesresultingfromthebreachofanyexpressorimpliedwarranty,in-cluding,amongotherthings,damagetoproperty,damagebasedoninconvenienceoronlossofuseoftheproduct,and,totheextentpermittedbylaw,damagesforpersonalinjury.

©2011,GrimmAudioCV.AllrightsreservedReproductioninwholeorinpartisprohibited.Specificationssubjecttochangewithoutnotice.

Grimm Audio MP1 manual v1.0, 11/17/11