Originally Posted by children of bodom
sorry I didnt clarify that, but the whole Channel B, so the second preamp is alot quieter.
Sorry to be a stickler, but you contradicted yourself here, so I still don't know what you mean. I think you mean the bottom preamp. But Channel B to me refers to the "lead" channel on both amp A and amp B. It's probably my fault because I think the output jacks on the back of the amp refer to amp 1 as "A" and amp 2 as "B" so my attempt to have you clarify probably made it worse.
Lets assume you mean the bottom preamp, or Amp 2. That's like the MKIII sound. You said your "channel B output knob doesn't work. If by that you mean that you can't control the volume of Amp 2, what did you expect? That it would magically be the same level as amp 1? :P
I'm kidding, but if that's the case, it's obvious where the problem is. To replace the pot you would either buy a new pot (exact same rating and taper) from an electronics supplier or call Boogie and get them to send/sell you one. Then you can adjust both amps to balance properly with eachother.
I wouldn't call it tube related just yet, although they do use a completely different set of tubes for each amp. The quickest free way to check if that's your problem is to swap all the tubes from amp 1 with the tubes from amp 2 and see if the output difference reverses itself.