The next one or two numbers are the month where January is 1 and December is 12. Example: AB763 = second revision, July, 1963 AA1070 = First revision, October, 1970 Misc Dating Info: Silver face amps with the aluminum trimmed grilles are from 67 or 69.
The fist Master volume controls were first installed in 72.
So if you find pots from late 68 and transformers from early 69 you can be pretty sure your amp is a 1969.
Fender installed casters on some larger amps and cabs beginning in 72.
Kay Musical Instrument Company was a musical instrument manufacturer of the United States, in operation since the 1930s until the 1960s.
"Acoustic Showdown, Part 2: Isn't a Dreadnought a Battleship?
"Acoustic Showdown, Part 3: Six Plus Six Equals Twelve" 20th Century Guitar Magazine, September 1998, p 26 - 27.
"Showdown: Gibson ES-125TD vs Gibson ES-135." 20th Century Guitar Magazine, January 1998, pp 27 - 28.