This model was also known as the Model 26 which was the same as the Princeton and Deluxe. Some of these models use a field-coil speaker, which has no permanent magnet. There were approx. 30 of these amps produced.

In 1950, the removable back paneling, which was originally a solid rectangle, had two holes cut in it, to let heat escape from the tubes.

Circa 1955/56, the choke was removed (Model 5C5). A standby switch was added for Model 5D5. Model 5E5 had the negative feedback loop removed, and 5E5-A had a fixed bias supply. The circuitry in this model was still linked with earlier models. In 1956, bass, treble, and presence controls were added. In 1957, a new nameplate was introduced.

The Brownface was Model 6G5. In late 1960, the tubes were changed and included preamp: 4 X 7025, 2 X 12AX7, power: 2 X 5881 (Model 6G5-A). This amp is almost identical to the Vibrasonic, except for the speaker, which was about $200 cheaper than the Vibrasonic.

The blackface Pro was the Model AA763 and featured a revised tremolo unit. This model faded out after the Pro Reverb amp was introduced. The Pro-Amp was on the cover of any Fender owner´s manual for amps.

This was the Model AA165.

In 1968, a change in the bias section occured (Model AB6686). In 1969, the cathode was brought back to ground (Model AA1069). In 1972, the output is increased to 45W by using a different rectifier, and increased voltage in the output stage. In 1976, a master volume knob is added and a pull distortion switch. In 1981, the Pro Reverb went back to the blackface. At this time the output was raised to 70W, the tubes were changed to: preamp: 4 X 7025, 2 X 12AT7, power: 2 X 6L6, and had twelve black knobs with a middle added to each channel.