I've got one of these - the bass version (electronically they're identical units, just with different labels on the controls!
). I love it. Build quality is very solid, and easy to maintain/tinker with. It's simple all-valve circuitry throughout: the only solid state devices in there are the diodes.
They also appear to have been shipped with very good valves in: I got mine 2nd hand a year or so ago. When I opened it up, it still had its original Peavey-branded valves, thick with dust. When I put them on my AVO CT160 tester, they came up with over 2mA/V each side (Mullard's original spec is 1.6mA/V).
The EQ setup is rather curious. The first bank is basically similar to a classic Fender stack; the second is a straightforward bass/middle/treble cut and boost stack. I installed a bypass switch which removes the first stack from the signal path for extra 'wallop'.
I have schematics if you need 'em. Just PM me.