To me, I always thought it had a "hot rodded" Bassman tone. The mid control works as a gain control after you go past 12. It's not a high gain amp. I would best descibe its gain, when mids are fairly dimed as "War Pigs" type tone.
I run P-90's on all my guitars. Very touch sensitive amp. Single channel, but tons of different tones by just rolling volume knob around. I'm mostly an "Americana" type guitar player..Just a touch of break-up..big gritty type open chords. HUGE reverb tank...Oil Tanker.
Hope this helps...There are a couple you-tube vids I've seen with BA's. Thanks for interest...Scott