This is one of the first guitar amplifiers produced by Gibson for the commercial market.
The various changes were made over the years to the E-150 amp. In 1937 the tweed case was enlarged and rounded on the left and right top edges, eliminating the need for the top four leather corner protectors (a transition model with the new circuit and the old cabinet has been reported, but these are either really rare or prototypical). Speaker size increased to a 12” field-coil with the Gibson name on the magnet cover.
A beefed up circuit employing seven tubes featured the relatively new 6L6 beam-power variety, in metal. The 5Z3 rectifier, 6C5 driver and 6F5 microphone channel preamp remained from the earlier model, but the twin triode 6N7 was replaced with two 6C5 triodes for the instrument and microphone channels.
Power ratings were given for the first time, a respectable 15 watts.
It appears this version ran for a number of years, as the picture and basic description from the late-’37 Catalog Y also showed up in catalogs Z from late '38 and AA from late ’39, plus AA supplements dated October 1, 1940, and May 20, 1941 (shown with the slant pickup on the instrument replacing the Charlie Christian-type of the earlier catalogs).
This Gibson E-150 amp was purchased by Steve Howe to partner his ES-150 guitar.
It featured an original Gibson "High Fidelity Ultra Sonic Reproducer"- a field coil 12" speaker. This was the premier amplifier of its day, as used by Charlie Christian.