The GA-20 was Gibson’s counterpart to the popular Fender Deluxe in the early 1950s. The preamp section on the GA-20 is comprised of a pair of 6SJ7 tubes while the power section uses a pair of the ever popular 6V6GT power tubes in a push/pull configuration. These amps have that smooth, natural breakup at relatively low volume that’s perfect for the house or studio. Go ahead and toss that overdrive pedal in the trash- you won’t even consider it after you hear the thick, luscious drive from this one.
This GA-20 is in excellent condition with only minor maintenance updates from my trusted tech Joseph Dorough of Great Dane Amplification. Joseph performed an expert and clean filter cap replacement and 3 prong cord installation. The rest of this amp is just how she came from Gibson’s Kalamazoo factory way back in the day. The original Jensen P12R is in great shape but I recommend swapping in a modern replacement so you can really enjoy the tone without worrying about blowing the fragile cone on these valuable old speakers. The Sylvania and GE 6V6GT power tubes are matched within one milliamp and test very strong. The preamp tubes are likely the original tubes as well. The rectifier tube is a GE 5Y3GT and is likely the one it originally came with. It’s very rare for amps like this one to retain the original leather strap but this one seems to be holding on strong. It’s clear from the condition that this amp was lightly played throughout the years.