A little light Googling revealed serial numbers for a few other amps in the range - they seemed all mixed up together.
Then the terrible truth dawned on me: they WERE all mixed up; Fender had decided to change their 35-year-old system of serial numbering so that, starting in 1982, every amp had a unique number.
Remember, your amp is newer than the newest component.
For example, if you find pots from late ‘64 and transformers from early ’65, you can be pretty sure your amp is a 1965.
latest updates; small changes to a few amp batches dates, Dec 2015, Feb 2016, July 2016, Sep 2016, March 2017 small changes to 4 amp batches, Nov 2015 typos found, two edits, thanks Ben H, June 20 info updated, totals unchanged Oct 2014 really nifty table design Aug 2014 small data and totals updates Jan 2014 (info updated In 2002 I acquired a Princeton Reverb II. Fender don't part with that kind of information*, so as part of the website I developed for this amp's care and feeding, I put out a call for serial numbers.
Eventually, I thought, I'll get a rough idea what the highest and lowest s/ns were.
Subtract one from the other and I'll have a rough-cut figure for how many were made. PRII owners were kind enough to start sending their serial numbers in.
I was puzzled to see how some of them were separated by over 100,000.
The following chart, was originally printed in VG magazine, by Gerald Weber.
If you see any data that is not listed here or notice any errors, for 1970’s and earlier Fender amps, please send us an email and we will update the chart.
However it’s unlikely that the transformer found its way immediately into production, so it’s a pretty sure bet that the a 1975.
It could be that another transformer reads 606602 which would make that component a 1976 make, thus the earliest the amp could be is a 1976.
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.