Dating fender champ amps
It is stamped into the chrome chassis with a white letter “C” (for Champ) and the serial number, also in white.
As you can see from the photo below, the serial number of my amp is C 09556.
First, to get a general idea,there’s the appearance/style of the amp.
I would have to collect data for ALL the amp types, just to work out how many were made of mine.
Then I became aware of the amazing work Greg Gagliano had been doing since the 1990s - the summary of his latest results are here - and that his research stopped just before the Rivera-era. However for this range of amps at least, I reckon it's not just a policy of withholding company-confidential information. It's no criticism of Fender to suggest that they were too busy making great amps to keep records just so some amateur can use them thirty years later.
While doing research on Fender amps in general, and the Champ in particular, I came across the most amazing series of articles by Greg Gagliano on the subject. If you have any interest in vintage Fender tube amps, without question you’ve got to read them all.
The process that went into figuring all of this stuff out over 6 years and countless owners of vintage Fender amps is hands down an amazing story.