MusicMan...."Something" Bass Amp? Help me out.

PepsiFX357 · 2nd November 2011

I have a MusicMan bass amp that was left over at my house, some 12 years ago by a bassist. I've kept it for quite a while. It's in pretty bad shape as far as cosmetics go, but it sounds amazing with a guitar!

I opened it up not too long ago and found a dime sized capacitor that broke off near one of the tubes. Looking at the other Tube, I can pretty much tell where it needs to go, but there are no legs left on the cap to solder too.

Anyway, I can't for the life of me figure out what kind of amp it is. I'd like to find a schematic and repair/modify.

There is no front grill or knobs. Some of the printed panels on the back are missing, so there is hardly any markings to go by. It is a musicman, as indicated by the logo near the standby switch. It has 2 6L6GC tubes that look original.

It has two "NORMAL" Inputs to the left with | Bright/Switch Volume - Treble - Middle - Bass
Two "BASS" inputs with | Bright/Switch Volume - Treble - Middle - Bass Deep/Switch and Master volume.

There are some markings on the side of the chassis, when you pull it out that says 2-24-RT and 75 with an upside down T on top. It looks like someone wrote on the circuit board 1.13.82, so I'm assuming that is when it was made.

The only other indicators that I could give, is that there are 3 Texas Instrument TL072CP op amps on the board. I'm assuming they are a part of the Solid State preamp. AND 1 texas instruments MC1458P on, what looks like the power supply maybe? I'm assuming, since there are voltage regulators and diodes on that board.

That's all I've got.

I'm sure someone knows what this thing is.

Thanks,

Ben

nedorama · 3rd November 2011

could be their 100B combo, sounds like their 2100-b chassis schematic is what you'd want.

Music Man Amps - Online Music Man Guitar Amplifier Resource

I had a 410 65RD, which also had a solid state preamp and power tubes.

PepsiFX357 · 3rd November 2011

Sorry, I forgot to mention the most obvious part.

Its a head. Not a combo. lol

Bullseye · 3rd February 2012

Ha. I had that head years ago. It was great...

Padster · 9th March 2012

Sounds like a HD130 Bass head. Beautiful, warm sounding tubes, if you can get it working optimally. Played through one for many years and still regret selling it on. Workable as a guitar amp too. I think they made a later model with transistor drivers - so have a peek in the back to see the circuitry.
Can't help with the capacitor tho. You could try contacting Musicman who might be able to point you in the right direction for a replacement.

2nd November 2011	#1
PepsiFX357 Gear addict Joined: Oct 2007 Location: Near Atlanta Posts: 352 Thread Starter	MusicMan...."Something" Bass Amp? Help me out. I have a MusicMan bass amp that was left over at my house, some 12 years ago by a bassist. I've kept it for quite a while. It's in pretty bad shape as far as cosmetics go, but it sounds amazing with a guitar! I opened it up not too long ago and found a dime sized capacitor that broke off near one of the tubes. Looking at the other Tube, I can pretty much tell where it needs to go, but there are no legs left on the cap to solder too. Anyway, I can't for the life of me figure out what kind of amp it is. I'd like to find a schematic and repair/modify. There is no front grill or knobs. Some of the printed panels on the back are missing, so there is hardly any markings to go by. It is a musicman, as indicated by the logo near the standby switch. It has 2 6L6GC tubes that look original. It has two "NORMAL" Inputs to the left with \| Bright/Switch Volume - Treble - Middle - Bass Two "BASS" inputs with \| Bright/Switch Volume - Treble - Middle - Bass Deep/Switch and Master volume. There are some markings on the side of the chassis, when you pull it out that says 2-24-RT and 75 with an upside down T on top. It looks like someone wrote on the circuit board 1.13.82, so I'm assuming that is when it was made. The only other indicators that I could give, is that there are 3 Texas Instrument TL072CP op amps on the board. I'm assuming they are a part of the Solid State preamp. AND 1 texas instruments MC1458P on, what looks like the power supply maybe? I'm assuming, since there are voltage regulators and diodes on that board. That's all I've got. I'm sure someone knows what this thing is. Thanks, Ben __________________ "That kick sounded like a turd hitting a trash can." "Ahh the power of the Guitar Center salesman over the adolescent teen wanting to be a rock star. Poor SAP." www.bencookemusic.com

3rd November 2011	#2
nedorama Lives for gear Joined: Jan 2008 Posts: 1,242	could be their 100B combo, sounds like their 2100-b chassis schematic is what you'd want. Music Man Amps - Online Music Man Guitar Amplifier Resource I had a 410 65RD, which also had a solid state preamp and power tubes. __________________ nedorama Monkey Boy Studios Summit 2BA-221, TLA-50 mBox Pro 3, Pro Tools 10.1.3 Radial JDI x 2, ProD2, ProRMP '65 Bandmaster 2x12 combo with Dr. Z Brake Lite, '65 Showman, '74 Princeton, '77 Princeton Reverb, Dr. Z. Mini Z Head, Dr. Z 1x12 Cab, pedals, George L's cabling

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3rd February 2012	#4
Bullseye Sub-Dude Joined: Nov 2011 Location: Harlem, NYC Posts: 306 1 Review written	Ha. I had that head years ago. It was great...

9th March 2012	#5
Padster Gear interested Joined: Mar 2012 Location: London Posts: 1	Sounds like a HD130 Bass head. Beautiful, warm sounding tubes, if you can get it working optimally. Played through one for many years and still regret selling it on. Workable as a guitar amp too. I think they made a later model with transistor drivers - so have a peek in the back to see the circuitry. Can't help with the capacitor tho. You could try contacting Musicman who might be able to point you in the right direction for a replacement.