Up for sale, a 1958 Gibson GA-20 in collector-grade condition and in perfect working order. Featuring original two-tone cosmetics, a positively gleaming chrome faceplate, original Jensen P12R speaker, and a very original and professionally serviced circuit, this GA-20 is the perfect mid-size combo from the golden age of tube amplification. In many ways analogous to Fender's narrow panel tweed amps of the same era, the GA-20 features a four input design with a 6V6 power tube pair, 5Y3 rectifier, and dual triode (12AX7, etc) tubes in the preamp.
Offering distinctly different voicings between the single Microphone input and the three Instrument inputs, the GA-20 is at its most aggressive via the Mic channel. While this input does offer a modicum of clean headroom, it quickly overdrives with a sizzling, chewy sound that's extremely smooth. The Tone control has an absolutely massive sweep, actually adding a bit more gain when turned up. Maxing out both Volume and Tone knobs yields a ripping, cutting sound that interacts equally well with single coils and humbuckers. The Instrument inputs have more range in the clean signal, with a full-bodied and sweet sound that works well with a host of effects pedals. Turning down the Tone knob on this channel and pushing the Volume can achieve a very nice bark and a spitty quality almost akin to certain fuzz boxes, depending on the guitar being used, and once again diming everything out delivers plenty of richness and roar.
The point-to-point circuit has been professionally serviced, and the preamp retains a trio of original yellow Astrons, the same capacitors used in Fender's narrow panel tweed circuits, and a key component in the musical nature of those preamps. There are a couple modern Mojo tubular caps in the preamp, and the power supply has been recapped with high quality F&Ts. Both original transformers are intact, with the output transformer mounted to the speaker frame. The speaker is the original Jensen P12R which has an extremely clean dark blue/green frame, blue foil label on the magnet bell, and the original smooth cone. The date stamp on the edge of the frame translates to the 4th week of '58.
The original two-tone black and fawn covering is remarkably clean, especially considering the fragility of this material compared to a conventional tolex or even tweed. The chrome plating on the faceplate is extremely nice, and the amp retains all of its original black silkscreen graphics. The gold Gibson badge is fully intact on the amp's face, and the luggage-style handle is also present.