Gibson GA40 Les Paul Amplifier Brown, 1952 – (No Longer Available)

Introduced in 1952 and built until 1954, Version 1 of the Gibson GA40 Les Paul amplifier was designed and built in-house at the Kalamazoo plant. It had two channels, with three ‘Instrument’ inputs on one channel and one ‘Microphone’ input on the other, and delivered 14 watts through a single Jensen P12Q 12 inch speaker.   Tremolo was offered from the very start.

The GA-40 Version 2  model was built from 1955 to 1960, with a new, less elaborate cabinet and ultimately many circuit changes.
Here we’re looking at a 1952 Version 1 example of the Gibson GA40 Les Paul Amplifier. The cabinet features a brown covering and basket-weave grille cloth fronted by large L P initials. To the right of the grille is the Les Paul signature, in the same script as the newly-introduced 1952 Les Paul guitar.

During 1952, 329 of these Version 1 amps were built out of a total of 3,621 over the three years of production.

This amp is in good condition and in good working order. There is expected wear and tear to the brown covering. The handle has been replaced, and for safety the AC power cord has been converted to a grounded 3-prong model. The single Jensen P12Q speaker and footswitch are original to this amplifier.

For tubes, this version of the  Gibson GA40 used 3x6Sj7, 1x6SN7 and 1x6V6 for the preamp section.   The power amp section had 2x6V6s and the rectifier was a single 5V4,  This arrangement produced 14 watts.

The GA-40 was Gibson’s longest-running, but not highest-production, amplifier. In 1960, the amp became the GA-40T – the T indicating the tremolo that had been there from the start. In 1962, with the end of Gibson’s contract with Les Paul, it became the GA-40T Mariner (inspired by NASA), and this was built until 1967.