We combined all of our information into a computerized database for this project and for the past 18 months have been slowly (sadly, very slowly) gathering information that we collect ourselves as well as from other people. What we need is the following: 1) Model name 2) Model number on the tube chart 3) Date code letters on the tube chart 4) Speaker codes (if speaker is original) 5) Transformer codes (if the amp doesn't have date codes on the tube chart) 6) Cosmetic features (flat/raised logo, tweed/tolex, blackface/silverface, rough/ smooth blond tolex, white/skirted knobs, TV-front/wide-panel, etc.) One very interesting and very important factoid has surfaced regarding the date code letters on the tube chart.In the fall of 1965, Fender switched from stamping these numbers in black ink, to dark green ink.
It is also advisable to add about 6 months to the date to allow for time these parts may have spent in storage.
If anyone has an amp with a "PA" stamp, please let us know.
Still, I wouldn't be too quick to just glance at that tube chart and accept an "OA" as a January 1965 amp.
Dating Fender Tube Amps by Serial Number, Part I by Greg Gagliano Copyright 1997, 20th Century Guitar Magazine. Well, we'll get to good parts, but first a little background information is in order.
After reading Teagle and Sprung's excellent Fender amp book, I took them up on their challenge that maybe someday someone will compile enough serial numbers so that Fender amps can be dated that way. I contacted several Fenders collectors and dealers who were kind enough to supply me with data.