This is the acclaimed Peavey Musician 400B also known as the 400 series. 210 watts to blow your hearing out, and knock the chest.
This is the one that has two channels and 12 knobs. I have printed a manual with binder that has all the info on this model, including schematics.
I wish I had the 5 button foot switch that adds another level of feature fulfillment, but there are other ways to achieve the same without it.
You can run one channel into the other, and a couple other things in regard to that, and also has reverb, tremolo, and two kinds of distortion. This circuit is based off of the Peavey classic amp. Pretty cool.