This Gibson amp model, and only this model, was blessed by Aspen Pittman in the several editions of his Tube Book. Mr. Pittman, who owns Groove Tubes and according to Tube Book, has a extensive collection of very fine vintage amps but the Gibson GA79RVT was the only Gibson amp to rate an 'Honorable Mention'. These are called stereo but they are more accurately 'dual mono'; there is no separate circuitry to distinguish Left from Right in the more typical meaning of the word 'stereo'. They all have on-board reverb and tremolo. Check your bank balance before bidding; all of these will likely go for $1,200 to $1,800.
Gibson Maestro GA78RVT; GA78 Auction Link a very rare 'Maestro' model:
Another - GA79RVT (#1) Auction Link
And another - GA79RVT (#2) Auction Link
Added November 4, 2007: Another GA79RVT GA79RVT (#3) Auction Link
These are rare amps; not many sold and fewer still around and very unusual to see three on eBay at the same time. cj
Gibson Maestro GA78RVT; GA78 Auction Link a very rare 'Maestro' model:
Another - GA79RVT (#1) Auction Link
And another - GA79RVT (#2) Auction Link
Added November 4, 2007: Another GA79RVT GA79RVT (#3) Auction Link
These are rare amps; not many sold and fewer still around and very unusual to see three on eBay at the same time. cj