[Gibson GA-20T Amp.]

only know about the 57 ga20t i have.not too loud but great tone when cranked

[Gibson GA-20T Amp.]

don't no where to get parts but i do own a 1957 ga20t.still has the original 12 inch jenson and wood trem foot switch.it was found in and attic and it looks as if it was drug behind the veh rather than puting it in.there is a local tube amp guru who put it back in playing condition for me.i know he found some tubes on the internet.this amp looks like #@!#*^#@! but man when it's fired up.i use a jump wire between both channels and roll both voulmns to about 8 plug in my 67 sg with p90s. it sound like a voice from heaven