Everyone knows that Gibson was a leader in the development of the electric guitar, but even though their amplifiers produce fantastic tone, Gibson amps have never commanded the high values of comparable vintage brands. Because of that, fantastic-sounding vintage Gibson amps are often overlooked.
Introduced in 1947, the GA-25 was Gibson's first post-WWII amplifier that broke from the designs of their earlier prewar amps. This short-lived model featured two mismatched speakers: an 8" and a 12." In 1948, it was replaced by the GA-30, which shared much of the same specs but updated cosmetics. While most GA-30s have three knobs (including individual volume controls for each channel), the early GA-30 as shown in the 1949 catalog featured two knobs like the GA-25. It also sports a bass "Tone Expander” switch which inserts or bypasses a low-frequency blocking capacitor in the negative feedback loop of the Instrument channel.
This circa-1948/49 Gibson GA-30 is the rare two-knob version. It was recently restored and improved by amplifier engineer Mike Crouchelli of Chelli Amplification in Durango, Colorado. When Mike first received the amp, it was mostly original, but the leatherette exterior had deteriorated and some of the 70+-year-old cabinet glue joints had separated. First, Mike removed the remaining bits of the covering and repaired the loose glue joints in the cabinet (which he was able to do while leaving all of the original cabinet pieces in tact). Second, Mike replaced the handle and recovered the cabinet in new brown leatherette covering. He was able to reuse the original grille cloth and logo. Next, he re-coned each of the original Jensen alnico speakers. Then, it was time to dig into the electronics! Mike replaced all of the power supply caps and tone caps, and he also checked all of the resistors and replaced any that were out of spec. Any tubes that were not functioning 100% were replaced with period-correct NOS tubes. Lastly, he replaced the power cord with a safe modern 3-prong cord. All of the original parts that were removed are included in the sale.
This 1948/49 Gibson GA-30 pumps out a modest 15 watts, which produces rich tone at lower volumes. The mismatched speakers offer an intriguing sense of balance, and it's interesting that this design has been lost with time. Thanks to Mike Crouchelli's meticulous restoration, it performs like a brand new amp, but its refined tone is unmistakably vintage.