"Universal Amps" 20th Century Guitar Magazine, October 1998, p 28 - 31.
"Showdown: Ampeg Reverbojet vs Guild Maverick." 20th Century Guitar Magazine, June 1997, pp 21, 139.
Serial Number: There is no information readily available for dating Fender amps by serial number but there are people working on it. Circuit Code: In 1963 Fender stoped using model numbers to identify schematics and began using the model name and an assigned circuit number.
These circuit numbers which are located on the tube chart can be usefull for getting a rough date on an amp.
Next, (if applicable) look for the date code on the tube chart.
If your amp dosen’t have a date code, flip the amp upside-down and check the transformers, and speakers for their manufacturer codes.
The code follows the format: XXXYY ZZ where: XXX = a two or three (possibly four on newer amps) digit number indicating the manufacturer.
"Showdown: Gibson ES-175 vs Guild CE-100D vs Gretsch 6117." 20th Century Guitar Magazine, April 1997, pp 16 - 17."Leo's Legacy, Part 2: Music Man and G&L" 20th Century Guitar Magazine, February 1999, pp 22 - 26."Dating Fender Amps by Serial Number, Part III" 20th Century Guitar Magazine, March 1999, pp 122 - 127.Fender often used the same circuit for many years so this is not a very accurate method for amp dating.The code is simple, the first two letters are the revision, where AA is the first revision, AB is the second, etc.