Thanks for the help, but I have to disagree about the -20dB cut in the 300-500Hz range.  That's more opinion than actual fact.  As clean sounds go, I really like this Bandit.  However, I'm coming from the perspective of a jazz/fusion style.  Most jazz players prefer a sound that is closer to flat than rock, country or funk players like.  In fact, I prefer the response of the Peavey tone stack to most Fender circuits.  Peaveys seem more responsive.

I'm not likely to ever design or build my own amp.  I already have a full-time job, a wife and two bands.  I'm also not likely to radically mod this amp, because for my purposes it isn't necessary, and because it's not a platform that's worth tinkering with.  I appreciate your input, though.

Customer service at Peavey sent me the pdf. Believe it or not, the tone stack is BYPASSED when the amp is in lead mode.  That is so weird!  I've never seen a design like it.  The only tone control available to the lead channel is the Presence control.

My version doesn't have the "pull thick", or any pull function.  It has button for "bright" on the clean side, and a button for channel switching.

If you use pedals for distortion/overdrive sounds, then all you need is clean, warm with headroom and reliability.  Portability and compactness are helpful, but you have to decide where your priorities are, but I use the above for my primary criteria.  That said, there are MANY inexpensive older amps out there that fit all the above for me.  I've used (and continue to use) Yamaha G100II and G100III amps, both 2-12 and 1-12.  GREAT jazz amps, but can do all styles due to very flexible tone controls.  I also have had great luck with Peavey's Bandits.  I use a 2nd generation Transtube that I keep at church, and I just picked up a Bandit 75 for gigging (to replace my Fender HRDeVille 410 and my Peavey Classic 30, both of which's tubes worry me during gigs).

I recently acquired a Bandit 75 on eBay.  I've noticed that the passive tone controls (T,M,B), while very effective in clean mode, seem to have no effect whatsoever in lead mode.  The presence control is very effective in both modes.  I've pulled the circuit board from the chassis to do basic cleaning, and while in there I saw no evidence of any modifications to the circuit.  However, it doesn't make sense for Peavey to have designed in a tone stack bypass for the lead mode.
Does anyone have access to a pdf of this schematic?