mxr M81 Manual

92503016739revA
M81 BASS PREAMP

SAMPLE SETTINGS
M81 BASS PREAMP
DESCRIPTION
• 3-BandEQwith
 sweepablemidrange
• Studio-qualityDirectOut
• ConstantHeadroomTechnology™
 forclean,crystalcleartone
DIRECTIONS
•Runacablefromyourbassto
theBassPreamp’sINPUTjack
andanothercablefromtheBass
Preamp’s1/4”OUTPUTjackto
youramplier.
•TheBassPreamp’sdefault
settingisDIRECTOUT‘ON’
Mode.TousetheDirectOut
function,runabalancedline(XLR
cable)fromtheBassPreamp’s
DIRECTOUTjacktoyourmixing
boardorPA.
•Setallcontrolstotheir12
o’clockposition.
•Turnthepedalonbydepressing
thefootswitch.
• RotateOUTPUTcontrol
clockwisetoincreaseoverall
volumeorcounterclockwiseto
decreaseit.
•RotateINPUTknobclockwise
toincreasePre-EQgainor
counterclockwisetodecreaseit.
•RotateBASSknobclockwise
toboostlowendfrequenciesor
counterclockwisetocutthem.
• UseMIDFREQcontroltoselect
midrangefrequencytobe
aectedbyMIDcontrol.
• RotateMIDcontrolclockwise
toboostmidrangeor
counterclockwisetocutit.
• RotateTREBLEcontrolclockwise
toboosthighendfrequenciesor
counterclockwisetocutthem.
• WiththeDIRECTOUT‘ON’,push
inthePRE/POSTswitchtoallow
yourDirectOutsignaltobe
aectedbyINPUT,EQand
OUTPUTcontrols.WhenPRE/
POSTswitchis‘out,’yourDirect
Outsignalwillbeunaectedby
thesecontrols.
BACK PICKUP FUNKCRUNCH
DUNLOP MANUFACTURING, INC.
P.O. BOX 846 BENICIA, CA 94510 U.S.A.
TEL: [phone] FAX: [phone]
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9
CONTROLS
OUTPUTknobcontrols
overallvolume
 GROUNDLIFTswitchengages
aDirectOutgroundlift
MIDFREQknobselects
midrangefrequencytobecut
orboostedbyMIDcontrol
 PRE/POSTswitchdetermines
whetherornottheDirectOut
signalisaectedbycontrol
settings
 INPUTknobcontrols
Pre-EQgain
 BASSknobcontrolshowmuch
lowendiscutorboosted
 MIDknobcontrolshowmuchof
midrangefreqiscutorboosted
 TREBLEknobcontrolshow
muchhighendiscutorboosted
FOOTSWITCHtoggleseecton/
bypass(blueLEDindicateson)
9
POWER
The MXR Bass Preamp is powered
by one 9-volt battery (remove
bottom plate to install), a 9-volt
AC adapter such as the Dunlop
ECB003/ECB003E, a DC Brick™
power supply, or phantom power.
SPECIFICATIONS
InputImpedance 2.2MΩ
1/4”OutputImpedance 300Ω,40Hz
BalancedOutputImpedance120Ω,40Hz
MaximummOutputLevel +22dBV
NoiseFloor*  -98dBV
THD  0.025%,1kHz
EQControls
 Bass  ±18dB,40Hz
 Mid  ±17dB,250Hzto1kHz
 Treble  ±18dB,4kHz
InputControl  PreEQ,±10dB
OutputControl PostEQ,+20dB,-50dB
Bypass**  True
    Hardwire
    Buer
CurrentDraw 8.25mA
PhantomPowerCurrentDraw 4.7mA
PowerSupply 9voltsDC
*A-weighted, all controls at mid position
**1/4” Output, Internally Selectable
• PushGROUNDLIFTbuttonin
toremovepossiblegroundloop
humwhenusingtheDirectOut.
DIRECT OUT AND BYPASS
TheBassPreamp’sdefault
settingisDirectOut‘ON’and
BUFFER1/4”OUTbypass‘ON.’
WithDirectOut‘ON,’Truebypass
isnotpossiblebecausetheinput
signalmuststayconnectedto
theinputbuerinordertosend
abypasssignaltotheDirect
Out.WithDirectOut‘ON,’the
BassPreampalsooers1/4”Out
Hardwirebypassandisselectedby
removingthepedal’sbottomplate
andbysettingswitchSW4tothe
down(‘OFF’)position.
PREAMP ONLY (TRUE BYPASS)
TheBassPreampcanbeused
withtheDIRECTOUT‘OFF’in
ordertoutilize1/4”Outtruebypass
switching.Toactivatetruebypass
switching,setSW4andSW5to
their“down”(‘OFF’)positions.(See
DiagramA).Thissettingdisables
theDIRECTOUTsignal.
Where should you put the Bass
Preamp in your effects chain?
Ifyou’reonlyusingtheBass
Preampforits1/4”Output,put
itatthebeginningofyourchain
ofeects.
WhenusingtheDIRECTOUT,
youhavetwooptions:
Tosendyourcleansignalto
thePAormixingconsole,putthe
BassPreampatthefrontofyour
chain.IfyouwantyourDIRECT
OUTsignalcoloredbyallofyour
othereects,puttheBassPreamp
attheendofyoureectschain.
PHANTOM POWER
TheBassPreampcanbepowered
throughitsDIRECTOUTfrom
equipmentthatprovidesphantom
power.Toutilizethephantom
poweroption,placetheBass
Preamp’sGROUNDLIFT
buttontotheoutposition.
(Diagram A)
DIRECT
OUT
BUFFER
1/4” OUT