Carvin Bx250 User manual

The BX250/MB Series MicroBass Amplifiers offer classic natural bass tone

with unprecedented tonal control and extended headroom. The BX250 Head

and Combo amps deliver 200w at 8 ohms and 250w at 4ohms.

Four discrete Class A input stages produce the harmonic basis for the preamp

right from the input jack. It begins with a boutique flat response, then we add

extensive tone control allowing you to carve out your signature sound. Harmonic

content increases as you turn up the DRIVE control producing rich harmonics

at maximum settings. The CLASS-D output and lightweight switch-mode power

supply use far less energy from the wall and produces less heat.

Light weight, solid design, bullet-proof construction and a list of indispensable

features make sure the BX/MB amps will be your choice for years to come.

 •DiscreteCLASSAinputstages

 •PreampDRIVEandMASTERvolumecontrols

 •2midsweepsemi-parametricEQ,BASSandTREBLE

 •CONTOURpre-shapecontrol

 •SingleknobCOMPRESSOR

 •DIRECTOUTbalancedXLRwithLEVEL,PRE/POSTandGROUND/LIFT

 •MUTEswitchallowssilenttuningorheadphonepractice

 •TUNER/PHONESoutputjackindependentofMUTEswitch

 •TWEETERDIMswitchallowscontrolofspeakerbrightness(combo)

 •CLASS-Damplifierrunscoolwhileconsuminglesspower

 •Solidmetalshaftcontrolswithpanelmountedthreadedmetalbushings

 •CircuitboardsareMILSPEC,doublesided,FR-4glassepoxy

 •Energyefficientworldwidepowersupplyaccepts90-250VAC,50-60Hz

 •Compactandlightweight.

GETTING STARTED

1.WithPOWERoff,connectaninstrumenttotheINPUTjack.Ifyouhavethe

BX250head,alsoconnectaspeakertoaspeakeroutjack.(4ohmsorhigher)

2.SettheDRIVEandMASTERvolumeto“0”andsettheACTIVEINPUTswitch

for your type of bass.

3.Setthefourtonecontrolstotheircenter“0”positionandtheCONTOURto

FLAT.Thisisthe“FLAT”settingfortheamp.

4.Now,turntheampON.Turnupthevolumeonyourbassguitar.Gradually

increasetheMASTERcontroltothedesiredlevel.Ifnosoundisheardturn

downtheMASTER,checktheMUTEswitch,speakerconnections,andthe

POWER(blue)/PROTECT(red)LED.

5. Increasing the DRIVE control will add harmonic richness to your sound.

TurninguptheDRIVEalsoincreasesvolume.Re-adjusttheMASTERvolume

after adjusting the DRIVE.

6.Adjustthetonecontrolstoyourliking.Keepinmindthatturningupatone

control isn’t always the answer. Sometimes turning down one of the MID

controls will get you the sound you want.

7.Needmorevolume?Thereisalimittotheamountofvolumeaspeakercan

produce and driving a speaker beyond it’s limit can damage it. Even though

these are powerful amplifiers, adding another speaker is the only way for

substantially more output. Doubling your speakers increases your acoustic

output by a factor of four.

Have fun exploring the features and sounds of your BX/MB amp. Take the

timewithyournewamptorealizeit’sfullpotential.

RECEIVING INSPECTION—read before getting started

INSPECTYOURUNITFORDAMAGEwhichmayhaveoccurredduringshipping.Ifdamage

isfound,pleasenotifytheshippingcompanyandCARVINimmediately.

SAVETHECARTON&ALLPACKINGMATERIALS.Intheeventyouhavetore-shipyour

unit, always use the original carton and packing material. This will provide the best possible

protectionduringshipment.CARVINandtheshippingcompanyarenotliableforanydamage

caused by improper packing.

SAVEYOURINVOICE.Itwillberequiredforwarrantyserviceifneededinthefuture.

SHIPMENTSHORTAGE.Ifyoufinditemsmissing,theymayhavebeenshippedseparately.

Pleaseallowseveraldaysfortherestofyourordertoarrivebeforeinquiring.

RECORDTHESERIALNUMBERontheenclosedwarrantycardforyourrecords.Keepyour

portion of the card and return the portion with your name and comments to us.

USAcustomersregisteronlineat:www.carvinaudio.com/pages/registration

SPECIFICATIONS:

OUTPUT POWER (all models)

8ohms, THD <1.0% 200w

4ohms, THD <1.0% 250w

Combo Speaker Configuration: MB10: 2-way; 10” LF / 1” NEO HF

(all models 8 ohms) MB15: 2-way; 15” LF / 1” NEO HF

MB12: 3-way; 12” LF / 6.5” NEO MID / 1” NEO HF

MB210: 2-way; 2x10” LF / 1” NEO HF

Input Impedance: >200K

Drive Control: Variesinputgainandharmoniccontent

Tone Controls: CONTOUR pre-shape

BASS 50Hz

2 semi-parametric MIDs: 50Hz-500Hz / 200Hz-2kHz

TREBLE 10kHz

AC Requirements: 90to250VAC50/60Hz

Power Requirements: 200VA

Dimensions

BX250 (HEAD):

3.7”Hx10”Wx7.25”D(93x254x184mm)

MB10:

18.5”Hx12.75”Wx11.5”D(470x324x280mm)

MB12:

18.5”Hx17”Wx12”D(470x432x305mm)

MB15:

18.5”Hx17”Wx12”D(470x432x305mm)

MB210:

24.5”Hx12.75”Wx11.5”D(622x324x292mm)

Weight : BX250 (HEAD):3.2lbs.(1.5kgs)

MB10:26.1lbs.(11.85kgs)

MB12:30.5lbs.(13.85kgs)

MB15:32.6lbs.(14.8kgs)

MB210:36lbs.(16.33kgs)

Warranty: Oneyearpartsandlabor

Optional Accessories: Extensionspeakercabs:115MBE1x15”,210MBE 2x10”

 Vinylcovers:CVMB10, CVMB12, CVMB15, CVMB210

MB15

MB10 MB12

BX250 HEAD

MB210

16262 WEST BERNARDO DR. SAN DIEGO, CA 92127

800-854-2235 CARVINAUDIO.COM

USER MANUAL

BX250 and MB series MicroBass Amplifiers

optional color shown

BX250/MB COMBO CONTROLS

1. INPUT JACK

The1/4”phonejackisahighimpedanceinstrumentinputdesignedto

handle both active and passive basses in connection with the ACTIVE

switch.

2. JEWEL LIGHT

BLUE = POWER ON/SYSTEM NORMAL

RED = STARTUP/MUTE/COMP/PROTECT

ThePOWERswitchturnsontheamplifier,andwhenthejewellightturns

BLUEtheampisreadyforuse.

The jewel light turns RED under different conditions. RED first appears at

POWERONforafewsecondswhiletheampstartsupandischeckedby

protectioncircuits.AsolidREDwillindicatetheMUTEswitchisengaged.

RED will FLASH as the COMPRESSOR is working. A solid RED (not

MUTEswitched)canalsoindicateaPROTECTmode,mostlikelyifthe

SPEAKEROUTPUTisshortedorifitisloadedbelowit’sminimumrating.

IfthepowerindicatorturnsOFF,orsolidRED(notmuted)whileplaying,

resettheampbyturningthePOWERswitchOFFforabout10seconds.

Checkanyexternalspeakerconnections.TurnthePOWERswitchbackON.

3. MUTE SWITCH

TheMUTEswitchturnsoffthesignaltotheamplifierandtheDIRECT

OUT.TheJEWELLIGHTchangestoREDtoindicatetheMUTEswitchis

on.TheMUTEswitchisidealforchangingbasses,silenttuningon-stage,

orheadphone-onlypractice.TheTUNER/PHONESoutputisnevermuted.

(BX250head:MUTE=in)

4. ACTIVE SWITCH

FliptheACTIVEswitchtotheDOWNpositionforstandardbasspickups.

If your bass uses a battery with an onboard active preamp, put the switch

intheUPposition.(BX250head:ACTIVE=in)

5. DI LEVEL (DIRECT OUT, PHONES)

TheDILEVELcontrolstheoutputleveloftheXLRDIRECTOUTandthe

1/4”PHONES/TUNERjack.TheDIlevelisnotaffectedbytheMASTER

level.UsePRE/POSTswitchtoselectiftheDRIVE,COMPRESSORand

TONEcontrolsaffectthissignal.

6. DRIVE CONTROL

The DRIVE control adjusts the input level to the CLASS A preamps. The

DRIVE control serves two purposes. The DRIVE can be used to adjust the

input sensitivity for the differences in bass pickups. The DRIVE will also

change the harmonic content of your sound. Turning the knob closer to

10 will create a more overdriven tone. The DRIVE will also change the

volumeoftheamplifier,useitincombinationwiththeMASTERcontrol

to achieve the desired volume.

7. CONTOUR CONTROL

TheCONTOURcontrolprovidesavariablemid-rangescoop.Whenthis

controlissetto“FLAT”thereisnochangetothemid-rangefrequencies.

As you turn the contour control clockwise, the mid range is scooped at

thecenterfrequency at 350Hz.Whenthe CONTOUR controlisset to

maximumthemid-rangeiscutby-15dBat500Hz.

8. BASS AND TREBLE TONE CONTROLS

TheBASSandTREBLE

controls are custom shaped tone controls designed to deliver punchy lows

andcrisphighsforavarietyofbasssounds.Whenacontrolisturnedto

the right it boosts the signal and when turned to the left cuts the signal.

TheaffectedfrequenciesfortheBASSstartat80Hzandcandeliveragreat

dealofvolume.Becarefulnottodistorttheoutputoroverpoweryour

speakers.TheaffectedfrequencyfortheTREBLEcontrolbeginsat5kHz

13 6 4 5 7 8 10 9 8 11

12 14 15 17 16 19 18

9. SEMI-PARAMETRIC MIS SWEEP TONE CONTROLS

(LO MID, HI MID & FREQ)

StartwiththeLOMIDsweep.TheFREQcontroldoesnotfunctionifthe

GAINcontrolissetinthecenter“0”position.Todemonstrate,turnthe

GAINtotherightforfullboost.NowplayyourbassandturntheFREQ

control from left to right and notice the how the added mids change

frequency.NowturntheGAINtothefullleftandturntheFREQcontrol

again and notice the mids disappear at different frequencies. Try this with

theHIMIDalso.Themidsweepsystemcontrolscanbeveryeffectiveto

fine tune your overall sound.

10. COMPRESSOR

The compressor reduces the volume of the incoming signal as it

reachesapresetmaximumlevel.AstheCOMPRESSORknobisturned

up (clockwise), the compressor reduces a percentage of peak signal.

Thispercentageiscalledthe“compressionratio”.Whentheknobisat

theOFFposition(fullcounter-clockwise)theratiois1:1,whereallofthe

input signal passes through the compressor without being affected. At

theMAXsetting,thecompressionratiois3:1.

The advantage of a compressor is to the reduce peaks and other sudden

loudparts(transients)ofyourplayingsoyoucanincreaseyouroverall

volume. For example, in slap bass playing the plucked notes can put out

peaks that would distort the amplifier at normal playing volumes. If the

amp’s volume was adjusted for these peaks, the rest of the notes would

betooquiettohearwiththeband.Whenthecompressorisadjustedto

wheretheJEWELLIGHTflashesREDforloudpeaks,theamplifiercanbe

played louder without distortion. It’s like having someone re-adjusting the

volume of the amplifier to help prevent distortion when the peaks occur.

11. MASTER VOLUME

UsetheMASTERtocontroltheoverallvolumeoftheamplifier.Reducethe

MASTERifyoursoundbecomesoverlydistorted.UsingtheCOMPRESSOR

will also help prevent distortion or overloading of your speakers.

12.

DIRECT OUTPUT XLR JACK (MUTED)

TheDIRECTOUTXLRjackprovidesabalancedindependentoutputstraight

fromtheinputjack(PRE)forgoingdirecttothemainPAorrecording

input. The output level is adjusted from the front panel DI LEVEL control.

ThisoutputiscontrolledbytheMUTEfunctionsoyoumaytuneyourbass

quietlywhileusingtheMUTE.TheDIRECTOUTsignalisnotaffectedby

the MASTER level. The DRIVE, TONEand COMPRESSOR controls do

notaffecttheDIRECTOUTwiththeswitchinPRE.TheXLRisprotected

againstPhantompower(DCvoltage)oncablescomingfromphantom

powered mixer inputs.

13.

DIRECT OUTPUT GROUND LIFT SWITCH

IfahumoccurswhenconnectingtheXLRtoamixer,tryusingthe

GNDLIFTswitch.TheGNDLIFTswitchliftsthegroundpin1oftheXLR

to100ohmsabovethechassisground.(BX250head:GND=out,LIFT=in)

14.

PRE/POST SWITCH

ThePRE/POSTswitchaffectstheDIRECTOUTandPHONES/TUNER

signal.Whensetto“POST”,theDIRECTOUTandPHONES/TUNERsignals

areaffectedbytheDRIVE,COMPRESSOR,andTONEcontrols.Whenthe

switchissetto“PRE”thesecontrolsarebypassed.TheDILEVELadjusts

thelevelinbothpositions.(BX250head:PRE=out,POST=in)

15. PHONES/TUNER JACK (UNMUTED)

The PHONES/TUNERjackisastereo1/4”jack,designedforconnecting

a tuner or headphones. Volume is adjusted by the DI LEVEL control. This

outputisunaffectedbytheMUTEfunctionsoyoumaytuneorplayyour

bassquietlywhileusingtheMUTE.

To listen to headphones without hearing the other speakers, turn down the

MASTERorturnontheMUTEswitchandadjusttheheadphonevolume

withtheDILEVELcontrol.ThePRE/POSTswitchaffectsthisoutput.

16. TWEETER DIM SWITCH (MB COMBOS)

The TWEETER DIM switch allows the internal tweeter to be attenuated,

allowing control of the brightness of the built-in speaker. This will not

affectanyspeakerspluggedintotheEXTSPEAKERjack

17. SPEAKER OUTPUTS

TheMB10,MB12andMB15haveone1/4”extensionspeakeroutputcon-

nectorwhichisconnectedinparallelwiththeinternal8ohmspeakers.You

may connect another speaker with an impedance more than 8 ohms. The

BX250headhastwospeaker1/4”speakeroutputs. The total impedance

must not go below 4 ohms. If you go below the minimum speaker load, the

ampmayshutoffortheJEWELLIGHTmayturnRED.Toresettheamp,

turnoffthePOWERswitchandconnecttherecommendedload.

SPEAKER COMBINATIONS/OHMS:

One16 ohm speaker + one 8ohm(MBspkr.)=5.33ohms(OK)

One8ohm speaker + one 8ohm(MBspkr.)=4ohms(OK)

One4ohm speaker + one 8ohm(MBspkr.)=2.66ohms(NO)

Two 8ohmspeakers=4ohms(OKforBX250 head)

18.

POWER SWITCH

ThePOWERswitchturnstheampONorOFF.TheJEWELLIGHTwill

lightREDforapproximately2-4secondsafterthethePOWERswitchis

turnedon,thenchangetoBLUE.IfitstaysRED,checktheamp.

19. AC POWER JACK & FUSE

TheACPOWERJACKwillaccept90VACto250VAC,60Hzor50Hz.A

detachablepowercordissupplied(forEuropean230VuseaCEE-7plug

cordset).Plugthecordintoagrounded3prongpowersource.Noattempt

should ever be made to use the amp without the ground connected.

TheFUSEislocatedinternallyneartheACinput.Tocheckorreplace,

first remove the power cord and then the enclosure lid. The fuse type is

a250VSlowBlowratedat5A.

12 15 17 19 18

BX250 HEAD REAR PANEL

CAUTION

RISK OF ELECTRIC SHOCK

DO NOT OPEN

SAFETY INSTRUCTIONS (EUROPEAN)

The conductors in the AC power cord are colored in accordance with the following code.

GREEN & YELLOW—Earth BLUE—Neutral BROWN—Live

U.K. MAIN PLUG WARNING: A molded main plug that has been cut off from the cord is

unsafe. NEVER UNDER ANY CIRCUMSTANCES SHOULD YOU INSERT A DAMAGED

OR CUT MAIN PLUG INTO A POWER SOCKET.

IMPORTANT! FOR YOUR PROTECTION, PLEASE READ THE FOLLOWING:

WATERANDMOISTURE:Applianceshouldnotbeusednearwater(nearabathtub,washbowl,

kitchensink,laundrytub,inawetbasement,ornearaswimmingpool,etc).Careshouldbetaken

so that objects do not fall and liquids are not spilled into the enclosure through openings.

POWER SOURCES:  The product should be connected to a power supply only of the type

described in the operating instructions or as marked on the appliance.

GROUNDING OR POLARIZATION:  Precautions should be taken so that the grounding or

polarizationisnotdefeated.

POWERCORDPROTECTION:Powersupplycordsshouldberoutedsothattheyarenotlikely

to be walked on or pinched by items placed upon or against them, paying particular attention to

cordsatplugs,Theapplianceinletisthedisconnectdevice.Keepitreadilyaccesable.

SERVICING:Theusershouldnotattempttoservicetheappliancebeyondthatdescribedinthe

operating instructions. All other servicing should be referred to qualified service personnel.

FUSING:Ifyourunitisequippedwithafusereceptacle,replaceonlywiththesametypefuse.

Refer to replacement text on the unit for correct fuse type.

REFER SERVICING TO QUALIFIED SERVICE

PERSONNEL! THIS UNIT CONTAINS HIGH

VOLTAGE INSIDE!

CAUTION

RISK OF ELECTRIC SHOCK

This symbol is intended to

alert the user to the pres-

ence of uninsulated “dan-

gerous voltage” within the

product’s enclosure that

may be of sufficient magnitude to con-

stitute a risk of electric shock to persons.

This symbol is

intended to alert the

user to the presence

of important operating

andmaintenance(ser-

vicing)instructionsintheliterature

accompanying the appliance.

RISK OF ELECTRIC SHOCK

DO NOT OPEN

76-45301F 122716

LIMITED WARRANTY

YourCarvinproductisguaranteedagainstfailurefor1YEARunlessotherwisestated.

Carvin will service and supply all parts at no charge to the customer providing the

unitisunderwarranty.Shippingcostsaretheresponsibilityofthecustomer.CARVIN

DOESNOTPAYFORPARTSORSERVICINGOTHERTHANOUROWN.ACOPYOFTHE

ORIGINALINVOICEISREQUIREDTOVERIFYYOURWARRANTY.Carvinassumesno

responsibility for horn drivers or speakers damaged by this unit. This warranty does

notcover,andnoliabilityisassumed, for damage due to: natural disasters, acci-

dents, abuse, loss of parts, lack of reasonable care, incorrect use, or failure to follow

instructions.Thiswarrantyisinlieuofallotherwarranties,expressedorimplied.No

representativeorpersonisauthorizedtorepresentorassumeforCarvinanyliability

in connection with the sale or servicing of Carvin products.

CARVINSHALLNOTBE

LIABLEFORINCIDENTALORCONSEQUENTIALDAMAGES.

MAINTAINING YOUR EQUIPMENT

Avoid spilling liquids or allowing any other foreign matter inside the unit. The panel of

your unit can be wiped with a dry or slightly damp cloth in order to remove dust and bring

back the new look.

Aswithallprogear,avoidprolongeduseincausticenvironments(salt

air).Whenusedinsuchanenvironment,besuretheamplifierisadequatelyprotected.

SERVICE

IntheUSAgotowww.carvinaudio.com.

OutsidetheUSA,contactyourdealerorgotowww.carvinaudio.com and click on

“Dealers”foryournearestservicecenter.Includeawrittendescriptionoftheproblem

with serial number and date of purchase.

Helpful Hints

1) NO SOUND:

TheMUTEfunctionhasbeeninadvertentlyengaged.

Speakers have been improperly connected.

2) NO HIGH FREQUENCIES:(MB10,MB12,MB15,MB210andexternalcabinets)

TheTWEETERDIMswitchorHIGHFREQUENCYATTENUATIONcontrolissetloworOFF.

The HF driver is damaged from too much power or distortion.

3) AMP SEEMS VERY SENSITIVE TO INPUT SIGNALS:

The drive control is turned all the way up.

The active switch may need to be turned on.

4) DIR XLR HUM:

TryswitchingtherearGNDLIFTswitchINorOUT.

Check for noise from external effects or bad cabling.

5)POOR BASS FROM MULTIPLE ENCLOSURES:

Makesuretheexternalspeakerisinphasewiththeinternalspeaker.Checkthewiringofeachcabinetiscorrectforphase,reverse(+/-)ontheexternalcabinetifneeded.

6)FOR MAXIMUM OUTPUT:

To get more output, use multiple speakers or enclosures. Every time you double your speakers, your acoustic output goes up by a factor of four.

LoadtheamplifierdowntoitslowestminimumimpedanceformaximumRMSpower.Ifyougobelowtheminimumload,yourampwillshutoffandgointothe“protect”mode.To

reset, turn your amp off and connect the recommended load.

The BX Microbass is a small, yet powerful amplifier. As with any amplifier, make sure your speakers are suitable for the available wattage. Driving speakers with too much wattage