The next time you get into a Fender Bassman discussion you should narrow down exact which era, model and circuit you’re discussing. The tube charts are not very useful for determining the circuit model.A lof of blackface Bassman amps with AA864 tube charts are actually AA165’s, and a lot of AA165 charts are glued into AB165 amps.Production years 1964 -1967 “blackface” circuits AA864, AA165, AB165 1967 -1977 “silverface” circuits AA165, AB165, AA270, AA371, AA568, AC568, AA864 Tube layout AA864 Tube layout (Seen from behind, V1 is to the right side): V1 12ax7 = Preamp bass channel V2 12ax7 = 2’nd gain stage bass channel (and normal channel for AB165) V3 12ax7 = Preamp normal channel V4 12at7 = Phase inverter V5 6L6 = Power tube #1 V6 6L6 = Power tube #2 Summary The Fender Bassman is a legendary guitar amp known to both guitar and bass players.
so let's go back a bit to have a look at the history of Fender amps, at some famous users, and find out which are the best Fender amps you can find today!
During the different eras the Bassman amp came in many different shapes and configurations.
Few other models experienced so many changes in terms of looks and tone.
In later years, the EIA converted to a 4 digit date code so the year could be easily identified.
There are 2 acceptable methods of displaying the EIA date code, with or without a hyphen between the manufacture code and the year/week code.