Mad Bean Pedals Dirtbag deluxe User manual

Dirtbag deluxe
11.2011madbeanpedals
Revised12.12.11–seepage5
PCBDimensions:3.2”Wx3.3”H

R1 2M2 R32 100k C1 100n C32 22uF D1 LED
R2 100k R33 16k C2 27pF C33 470n D2 1n914
R3 22k R34 16k C3 1n2 C34 47n D3,D4 1N4001
R4 100k R35 33k2 C4 47uF C35 1uF D5 8.2vZener
R5 47k R36 24k3 C5 22n C36 470n
R6 150R R37 470R C6 1uF C37 2u2 IC1 TL072
R7 100k R38 15k C7 220n C38 2u2 IC2 NE570
R8 200k R39 16k C8 10uF C39 1n IC3 TL072
R9 200k R40 15k C9 4u7 C40 1n IC4 ***
R10 68k R41 39k C10 1uF C41 240pF IC5 ***
R11 * R42 11k C11 2n7 C42 100n IC6 TL072
R12 * R43 1M5 C12 2n7 C43 100n IC7 TL062P
R13 24k R44 100k C13 1uF C45 100uF IC8 TL072
R14 51k R45 240k C14 33n** C46 100uF IC9 CD4047BCN
R15 16k R46 180k C15 1uF C48 10uF
R16 33k R47 330k C16 1uF C49 10uF Q1 2N5087
R17 33k R48 1k C17 10uF C50 100n
R18 11k R49 15k C18 220n CH/VB SPDT
R19 22k R50 3k3 C19 2n7
R20 820R R51 13k C20 2n7 BAL 5k
R21 1k** R52 910k C21 4u7 BIAS1 100k
R22 82k R53 910k C22 47n BIAS2 100k
R23 6k8 R54 120k C23 2n7 GAIN1 100k
R24 2k4 R55 7k5 C24 2n7 GAIN2 100k
R25 2k4 R56 27k C25 4u7
R26 100k R57 27k C26 4u7 BLEND 10kB
R27 100k R58 5k6 C27 3n9 DELAY 100kB
R28 39k R59 100k C28 1uF FDBK 10kA
R29 6k8 R60 100k C29 1uF LEVEL 1MA
R30 100k R61 100R C30 150pF MOD 100kB
R31 680k R62 7k5 C31 120pF
Resistors Resistors Caps Caps Diodes
ICs
Transistors
Switch
Trimmers
Pots
*R11,R12:68kifusingMN3005,47kifusingv3205
***IC4,IC5:MN3005orv3205

WhatIsIt?
TheDirtBagDeluxe(basedontheEHXDeluxeMemoryMan™)allowsyoutobuildwhatisprobablythemostloved
bucketbrigadedelayofalltime.Itoffersaround550msofpureanalogdelaywiththeadditionofchorusorvibrato
modulation.TheDirtbagalsoincorporatesmodernaccoutrementsviatruebypassoperation,centerpinnegative9–
15vDCoperationandtheabilitytousedifferentversionofcurrentlyavailableBBDchips.
WARNING:Thisisanincrediblydifficultproject.Thisisnota“firsttime”buildbyanymeans.DonottakeontheDirtBag
unlessyoufeelconfidentinyourabilities,oryoumayendupwastingquiteabitoftimeandmoney!Thatsaid,ifyoutake
yourtimeandfollowtheinstructionscarefully,youshouldbeabletogettheDirtBagworkingwithrelativeease.
Developmentofthisprojecttookplaceoverseveralmonths,andshouldberelativelybugfreedespiteitscomplexity.
SpecialthankstoforummemberScruffieandFSBmemberDirkHendrikwhoprovidedinformationandfeedbackduring
thisprocess.
Controls
LevelThisadjuststheamountofgainattheinputstageofthecircuit.
Blend–Thiscontrolstheamountofdelaysignalmixedinwiththesignalfromtheinputstage.
Delay–TheoveralldelayproducedbythetwoseriesBBDdevices.Counterclockwiseisslapbackandfullclockwise
shouldyieldabout500–550msofdelay.
Fdbk–Thisistheamountofdelaysignalfedbacktotheinputofthedelaychain.Itcontrolsthenumberofdelayed
repeats,
Mod–Thissetstheoverallmodulationofthedelaysignal.Counterclockwiseisnomodulation.
CH/VB–StandsforChorus/Vibrato.ThisSPDTswitchsetsthetypeofmodulationusedbytheModcontrol.Chorus
producesaverypleasing,spatialspreadtothedelaysignal.Vibratoyieldsshorterpitchshiftingarounddelayednotes.At
lowModsettings,themodulationisbothsubtleandmusical.AthighModsettings,themodulationbecomesveryintense
andwillproducesomewild“seasick”typeeffects.
Notes
TheDirtBagDeluxecanbebuiltwiththreedifferenttypesofBBDdevices.ThefirstistheMN3005,whichwereusedin
thevintageDeluxeMemoryMan.SecondistheMN3205,whichhavelowercurrentconsumptionanddifferentpower
requirementsthantheMN3005.Finally,theDirtBagcanbebuiltwiththeCoolaudiopinforpincloneoftheMN3205:the
v3205.Thesearereadilyavailableandusedinanumberofmodernanalogdelaypedals.
ThebadnewsisthattheMN3005andMN3205arescarce;muchmorenowthanjustacoupleofyearsago.It’sagood
betthatifyoudonotalreadyhavesomeoftheseinyourpossession,thenyouwillhaveaverydifficulttimelocating
genuinechips.TherearemanycounterfeitandrelabeledchipsbeingsoldoneBayandelsewherethatpurporttobe
MN3005(or3205).Forthisreason,IrecommendnotbuyingthesefromunknownoroverseasvendorsoneBayunless
youhavegoodreasontobelievetheyaregenuine.YoumaybeabletogetsomethroughmembersoftheDIYcommunity
oraninternationalbrokerlikeUTSource.However,evenUTSourcehassentoutsomefakes(mostlikelyunknowingly)in
thepast.
ThegoodnewsisthatevenintheabsenceoftheMN3005andMN3205youcanstillbuildatotallyrighteousanalogdelay
withthev3205.Theseareeasytoget,andcanbepurchasedfromsmallbearorsimilarvendorsforabout$4.50each.
What’sthedifference?Dothedifferentchipssounddifferent?
Yes.Theysounddifferent;but,onlyaverylittlebit.Thebiggestdifferenceisn’treallyintheactualtechnologybehindthe
chips,butmorelikelyinthevoltagethatrunsthem.TheMN3005canberunoff15vandtheMN3205andv3205mustbe
poweredunder9vtooperateproperly.TheaddedheadroomallowedbyrunningboththeBBDandrestofthedelaycircuit
at15v(liketheDeluxeMemoryMan)canaccountforslightdifferencesintonalityandwarmthproducedbytheeffect.
However,thisdifferenceissubtleandwhateveraddedheadroomonegainsisalwaysmitigatedbythefactthatanalog
delay,atitscore,isasounddegradationdevice.Thepurposeofanalogdelayistodestroythepurityoftheinputsignalin
incrementalbitsovertime.Thatiswherethe“warmth”oftheeffectiscreated.
HavingbuiltmanyanalogdelayswithdifferentBBDdevicesIcanhonestlysayIlikethemall,andwouldhappilyuseany
versionIhadavailable.Therealmagicinanalogdelayishowyouinteractwithit.Findingtherightdelaytime,repeats,
blendandmodulationandplayingoffthosedynamicallyiswhereit’sat:it’snotinthebitsandpiecesinthebox.

IOW:don’tsweatit!Buildtheversionwiththepartsyoucangetandforgetaboutit.IfyoulikethewaytheMemoryMan
soundsthenyouwilllovetheDirtBagDeluxe.
IfyouplanonbuildingtheMN3005,youwillneedtoutilizeaRoadRageboard,orsimilarchargepumpdesign,tosupply
theboardwith15vDC(regulated)insteadof9v.PleaserefertotheRoadRagedocumentationontheProjectspageofthe
madbeanpedalswebsiteformoreinfo.YoushoulduseanLT1054chargepumpandanLM7815ACTorsimilarregulator
(theT0220typewhichprovidesupto1Aofcurrent).
REVISION(CRITICAL):Somebuildersofthev3205versionofthisprojecthaverunintodistortedrepeats.There
isasimplesolutiontothisissue.ReplaceR21(1k)with100kandC14(33n)withanother100kresistor.Thisforms
avoltagedividerwhicheliminatesoverloadingthelowerheadroomofthev3205.Theoriginal1k/33nformsalow
passfilterwithacornerfrequencyofabout4825kHz.Eventhoughthisfixeliminatesthisfilter,itseemsthatthe
lowoverheadofthev3205doesnotimpactthedelaytoneinasignificantway.FurthertestsalsofoundthatR10
couldbeomittedfromthecompressorportionoftheNE570,butthisisnotcritical.Asareminder,youwillwant
touse47kforbothR11&R12whenbuildingthev3205version.
Let’sBuildIt
TherearethreejumperstosetontheboardunderIC5dependingonwhichBBDyouareusing.Note
thatyoudon’twanttomixandmatchBBDs.YouneedtousetwoMN3005,twoMN3205ortwo
v3205devices.
MN3005
v3205(MN3205)
ThesejumpersconnecttheVDD,groundandVGGpinsofbothBBDstotheirpropersourcessimultaneously.The
MN3005takestheVDvoltageonpins1,groundonpin5andVGGisconnectedtogroundonpin8.Forthev3205,pin1
connectstoground,pin5connectstoapproximately8.2v(VD)setbyD5andVGGisabout14/15oftheVDvoltage
throughthevoltagedropoverD2.
NotethatifbuildingtheMN3005,youshouldomitD5fromtheboard.The8.2vZenerisonly
usedforthev3205/MN3205.YoushouldalsoomitD2andC17.
Aftersettingthejumpers,IrecommendpopulatingtheboardwithalltheresistorsINORDER.Thiswilllessenthechance
ofplacingthewrongvalueresistorinaplacethatcouldlatercauseproblems.Soldertheresistorsinplaceonthebottom
oftheboard.
NotethatfortheMN3005,R11&R12needtobe68k.Forthev3205/MN3205theyshouldbe
47k.
Ifyouwanttogotheextramileyoucantopsoldertheresistors,too.Thisisnotnecessaryfortheeffecttofunction
properlyprovidedyouhaveusedgoodtechniqueonthebottomside,butitdoeslenditselftoamoreprofessionallook.

Justbecarefulnottoapplytoomuchsolderorheattothepadsasthiswillresultinlargesolderbulbsorpotential
componentdamage.
Aftertheresistors,placealltheICsocketsandtrimpotsontheboardandsolderinplace.
Takealittlebreak…nokidding.
Finally,placetheremainingcomponents,thefilmandelectrolyticcaps,diodesandtransistorsandsoldertheminplace.
Expecttospend23hoursonthisprocess….therearealotofparts
Animportantnoteonsomecomponents:
ExtracareshouldbetakenwithC41,the240pFcapusedtosettheclocksignalonIC9.Youwanttouseascloseto
240pFaspossible.Notethatmanyceramiccapsmeasurewellundertheirstatedvalues.Ifyouhaveamultimeterthat
readscapacitance,measureafewoutandpickthebestone.Youcanalsoadddifferentvalueinparalleltogetcloseto
the240pFvalue(rememberparallelcapsresultinthesumoftheirindividualvalues).Ifyoudon’thaveacapacitance
meter,considerusingaSilverMicacaphereinsteadofceramic.YoucanalwayssocketC41andusewhatyouhaveon
hand.AfterbiasingtheBBDs(detailsbelow)youcangobackanddropdifferent240pFcapsintoseeiftheyincreasethe
delaytimeatall.
Similarly,beforesolderingthePCBmountedpotsmeasuretheresistancebetweenlugs3&1ofseveral100kBpotsand
picktheoneclosesttotheactual100kvalue.UsethisoneforyourDelaypot.Again,thiswillgiveyouthewidestrangeof
delaytime.
Nowthatyouhavethatsortedout,loadyourpotsandswitchonthePCBandsolderthemup.NotethatthisPCBallows
for16mmshortpinPCBmountedpotsunderneaththeboard,andasolderlugSPDTswitch(alsomountedunderthe
board).
Onelastthingbeforemovingontobiasing:D1isthe“overload”LED.ThisLEDwillgiveyouvisualfeedbackonthe
amountofsignalcomingoffthefirstcoupleofgainstagesoftheeffect.ThehighertheLevelpotisset,thebrighterthe
LEDblinks.Thiscanbesolderedinpace(justaboveC45)oryoucanrunwiresfromtheboardtotheLEDfordifferent
placementlocations.Ifyoudonotwishtousethe“overload”LED(it’smainlyavisualeffect)youcanomitR18,
C13,R19,Q1andR20fromthePCBalongwiththeLED.
Biasing
BiasingtheDirtbag foroperationisactuallyprettyeasyandcanbedonewithoutascope.Youwillneedtouseanaudio
probe.Beforeconnectingtheboardup,settheBIAS1,BIAS2andBALtrimmerstotheirmiddlepositions.SettheGAIN1
andGAIN2trimmersfullycounterclockwise.Finally,settheLevelsomewhereinthefirsthaveofitsrotation,Blendabout
¼up,Delayabouthalfwayup,ModfullycounterclockwiseandFdbktoaboutthemiddle.
Nowconnecttheinputfromyourguitar(orsignalgenerator),theoutputtoyourampandpoweruptheboardwithyour
powersupply(makesureyouhaveacommongroundconnection).Testtoseeifyouaregettingsignalthroughtheeffect.
Youmayormaynothearanydelayatthispoint.Youshouldbeabletohearvolumechangeswhenincreasingor
decreasingtheLevelcontrol.Ifyoudonotgetanysignalthrough,recheckyourconnectionsandmakesurethereareno
errorsinyourbuild.
Onceyouhaveverifiedthepassthroughsignal,disconnecttheoutputtoyourampandconnectyouraudioprobetothe
amp.Nowyouwillbeabletoprobetheaudiosignalontheboardwhereveryouplacetheprobetip.
Probepin3ofIC4whilesendingsomesignalthrough.AdjustBIAS1untilyougetthecleanestdelayedsignalpossible.
Repeatthesameprocesswithpin3ofIC5.AdjustBIAS2untilyougetthecleanestdelayedsignalpossible.Youshould
beabletoleavetheBALtrimmerinitsmiddleposition.
NowreconnecttheoutputfromthePCBtoyouramp.Youaredonewiththeaudioprobe.
Nowwewillsetthegaintrimmers.TurnyourFdbkpotallthewayup.Itmayormaynotselfoscillateatthispoint.Ifit
doesoscillate,youdonotneedtomakeanyadjustments.Ifitdoesnot,turnbothGAIN1andGAIN2incrementally
clockwise.Youwanttomakesmallchangessimultaneouslytothetrimmersuntiltherepeatsstarttoselfoscillate.Once
youreachthispoint,youarefinished.

Notethisisthe“layman’sway”ofbiasingtheDirtBaganditworksquitewell.Ifyouwishtouseascopetoprofessionally
configureitsoperationpleasetakethetimetoGooglethefactorysetupguidefortheDeluxeMemoryMan.Youshouldbe
abletofindinformationonboththeEHXwebsiteandsomeonFSB.
Wiring
ThisisthewiringfortheMN3205/v3205version.IfyouarebuildingtheMN3005version,youneedto
useaRoadRage(orsimilarchargepumpdesign)for15voperation.PleaserefertotheRoadRage
documentationforinformationonbuildingthechargepump.
Thegreencirclesindicategroundpads.Youdonothavetouseallofthem.Theyaretherefor
convenience.

DrillTemplate1590B
5.8”Wx6.8”H@borders
Thistemplateisapproximate.Pleasecheckcarefullybeforecommittingto
drillingyourenclosure
Licensing
TheusermayutilizeapurchasedDirtBagDeluxePCBfrommadbeanpedalsforDIY/noncommercial
purposes.YoumaynotusetheartworktosellyourownversionofthePCBdesignoraspartofa“kit”
orsimilarcommercialproduct.
www.madbeanpedals.com