On the lead channel if you have the "pull thick" engaged the tone controls are pretty well bypassed. Push the mid-tone control in and you should have full control. This is only applies to the lead channel. It has no effect on the clean channel.
See the Peavey website under archived manuals for a full description. The Peavey Amp Forum will post a wiring diagram if you ask.
See the Peavey website under archived manuals for a full description. The Peavey Amp Forum will post a wiring diagram if you ask.