AA763 was the first circuit that Fender used and didn't last long.
Soon after the circuit became the famous one, the AB763. Amps such as the Pro Reverb (AA or AB165, came out in late '64) and the Vibrolux Reverb (AA864, came out in late '64) are identical to AB763 circuits and are still considered the "good" ones.
Comes equipped with Celestion Speakers (V Type) for a more modern, punchy sound that breaks up nicely when pushed.
Reduced negative feedback lends a more "touch-sensitive" feel, quicker break up and added harmonic richness.
Due to its high power and clean tone this amp is often preferred by pedal steel, country, and jazz players in its unmodified state.
This was achieved by incorporation an "Ultralinear" design power transformer which has an additional set of taps on the primary windings that connect to the screen grids of the tubes, increasing the output and creating a more "hi-fi" sound.This amp is squeaky clean and painfully loud, both of which are magnified by the factory installed JBL D-120F speakers.These speakers are labelled "Fender Special Design" and feature a distinctive orange and black paint job with massive Alnico magnets.Numerous design changes followed, resulting in at least 13 revisions and variations on the 1176.Most units include the revision letter with the serial number.