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.
These 1965 codes begin with the letter "O." The code for the year 1966 is "P." However, someone in the factory apparently forgot to switch the stamper from "O" to "P" in January 1966.
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.
I turned to the Internet to do some more networking which resulted in a major turn of events as I met two individuals who have become instrumental partners in this project: Greg Huntington and Devin Riebe.
Greg is a long time Fender collector who is very knowledgeable not only in the details, but in the circuitry as well.
His particular area of expertise is in Fender amps made from about 1960 through 1967.
Devin runs Doc's Music in Springfield, Missouri and his interest lies in the woodie and tweed Fender amps made from 1946 through 1960.
Greg and Devin's experience meshed well with mine since I'm essentially the blackface/silverface amp guy (amps made between 19) in the group.
Additionally, Greg and Devin also had data that they had been collecting from Fender amps for years. Everything is confidential, we don't make record of who owns what amp in the database.
The factory realized its mistake in February because these amps have a "PB" date code in black ink.
Now, we obviously haven't looked at every amp made in January 1966 so this isn't set in stone.
If anyone has an amp with a "PA" stamp, please let us know.