We’ll come back to this later in the “blackface chapter” below where we’ll demystify some of the hypes with the popular AA864.The AA165 is very rare and its circuit and tone is quite similar to the AA864.

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.

At the Fender factory they used old tube charts when new models came, probably because the tube layout was the same.

Determining production date by serial number and transformer codes is better, and you should also inspect the circuit to be completly sure.

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.

It was introduced in 1951, primarily targeted for bass guitar players and promoted as a bass amp for the Fender Precision Bass guitar, the first mass-produced electric bass guitar ever.

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.

The picture below shows a 1969 transition model amp.

Unfortunately the Bassman was one of the first amps that CBS laid their hands on after buying the company from Leo Fender.