3 years later...(I haven't been on here for longer than that), according to the manual, 1-5 the mid control is like a normal mid, after that it adds gain and starts to accentuate the high mids more. This is only on the rhythm channel.
Pull the gain pot and set it relatively high. You will have to use the GEQ to shape the tone though as the boost is created by removing the pre distortion tone stack from the circuit.
If the tone stack is removed, why does the manual say to set treble and mid high and bass and presence low...
If that's the one I'm thinking of, it has Yellowjackets or Substitubes in it, those are adapters to allow EL84's to be used. The amp is meant to use 6L6's. Pull out the entire setup and use 6L6's (if you want). I used Substitubes on mine for a while. Went back to 6L6's.
Don't know if this will help but...
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CGsQFjAA&url=http%3A%2F%2Fhomepage.mac.com%2Fmesaboogie%2Fdot.html&ei=I1vCT8fGGMjJ6gHX9dCbCg&usg=AFQjCNEakkSdXBlB-Jqa5b9LpgXRmFtAWA
Are you kidding? I guess you never listened to Ozzy's "Speak of the Devil", Brad Gillis playing through 2 MKIIB's, separated by a stereo chorus. Absolutely killer rock tone!
It helped a *little* bit at wife volume, but I don't notice enough difference at band volume to say it's a must. I'd have left it alone if I had known the lack of difference. but that's just me...