@golem brought his 1967 GA-35 to me in January, barely running and sounding like crap. Then I told him to go watch Youtube videos on GA-35's - they all sound like crap. They were designed by hearing-impaired engineers. I am surprised these were in the Gibson catalog as long as they were. He gave me carte-blanche to redesign, with the desire to make it Fender Deluxe Reverb like. It ended up even better: a 1964 Deluxe Reverb, meets a 1957 Tweed Deluxe, meets a Fairchild inter-stage (it has a transformer inverter, which drives the power tubes). Channel 1 is more scooped like a FDR. Channel 2 is Tweed with lush spring reverb & vibrato. Replacing the 12AU7 driver (V6) with a 12AT7 you loose the vibrato, but gain really awesome harmonics from the inner-stage transformer. There is not much of the original circuit that is left, nor copying Fender, etc. It is more my own design than those it sets to emulate (I actually had to draw a schematic to ensure it could be repaired in the future). Replaced the speaker with an early 80's Pyledriver 12", new reverb transformer and tank. I used many of the original RCA 9-pin tubes and converted the output tubes from 7199 to 6V6. Although, it is set up to also use: 6L6, EL-34 & 6550s. This is probably the best single 12" combo amp I've ever heard. It really gives back to the player and is very pedal friendly. It is loud enough to be used with a drummer, but not ear splitting. The exterior came out nice as well (vinegar wash - black shoe polish finish!).