Gibson's amplifiers have no public serial-to-year chart, and the company's own lookup is for instruments. The model carries the date instead — GA, BR, EH, GSS, THOR and G numbers with their versions — and EIA component codes give the second witness. On many combos the Jensen speaker, whose code is stamped under the magnet bell cover, is the only original dated part left.
Gibson entered amplification in the 1930s from Kalamazoo, and the early EH and BR numbers sit in this window with modest output and a single small speaker.
The GA numbers multiplied through the 1950s, and the same number was reused for different versions: the GA-40 appears as a first version (1952–54), a second version (1955–60) and then a GA-40T (1961–62).
The 1960s brought reverb-equipped GA models and the GSS and THOR solid-state lines. Model-era dating is the primary instrument, because the chassis numbers do not form a series.
Gibson reissued several classic designs at the end of the 1990s and in the 2000s as separate models, so a GA number alone does not prove a vintage amplifier.
12 Gibson (amps) models are catalogued with their production years, specs and safety notes.
Browse the models →No. Gibson has no public amp serial chart, so the model and its version carry the date, with EIA component codes as the second witness.
Jensen drivers use the usual maker-year-week form, but on many Gibsons the code is stamped under the magnet bell cover, which has to come off first.
Because it was replaced. On the documented GA-40 four pots agreed with the 1956 amplifier and the odd one read 1966.
Treat the reissues as separate models with their own windows, and check construction and components against the version they claim to be.
Compiled from 150 published sources — the source library.