This makes things a little more interesting and difficult in playing the "dating game." And yet there is another variable to contend with as it appears that models that share chassis may also share the same serialization scheme.For instance, the Bandmaster Reverb and Super Reverb share the same chassis, and the Twin Reverb, Quad Reverb, Dual Showman Reverb, Vibrosonic Reverb, and Super Six all share the same chassis.
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.
We just don't have enough data to make any definitive conclusions yet. The author and his partners would like to thank those people who have sent us Fender amp information, especially James Werner, Tim Pershing, Gregg Hopkins at Vintage Amp Restoration, Jim Strahm and Matt Kesler at Midwestern Musical Co., and Tim Nelson at Mass Street Music.
We will be writing articles in the future with more fun factoids (yes, there's more! Also thanks to the many dealers at the various guitar shows that we visit for allowing us to make notes about the amps at their booths.
Our evidence is that we are finding some serial numbers duplicated between models.