I've got an AD30 head and it sounds awesome, especially with either a Les Paul Special w/ the P-90's or a Dan Armstrong running through it-sizzling but not generic-sounding. It was expensive though, so I guess you'd hope that it would do more than just look cool.
it's combo, but TC means twin channell, it has 2 independed pre-amps with independed controls and gain for each, what makes it different from any other amplifier that have just gain/overdrive on/off switch. it is equipped with 2 celestion vintage 30 12" speakers.
Frank Zappa plays on Orange at the June '71 Fillmore concert(s) (largely documented gigs - for instance on Lennon/Ono's "Sometime in New York City", the side with the jam with the Mothers.
I think this amp had a great palette in this setting. Zappa played that famous semi-hollow Gibson I never remember the model # of... KR has also been using a lot as of late...
----------------------------------------------------- Oh, give me the beat, boys, and free my soul I wanna get lost in your rock and roll and drift away
Yeah, that's the one, thanks! Zappa's was a "stereo" model AFAICR. He had distorsion or something on one channel and a clean feed on the other (in a live context).