I run a couple of websites making the schematics for these amps easily accessible.

As people download them, I'm hoping they'll respond to my request that they send me their amp's serial number for this project, and many do.

According to Tom Wheeler's excellent book about the Stratocaster, it may be that they had no factory after December 1984!

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For a while I also had automated searches running on e Bay for these 14 amp types - whenever one appeared for sale I would contact the seller, asking for the serial number.

9 out of 10 did - many thanks to them for their trouble and good will.

Advertisers and politicians make decisions based on smaller percentages!

I'm guessing amp-owners like to know when their amp was made, if it's old-ish.

If you've got one of the 14 amp models in this range you can get a rough idea of its date-of-manufacture from these tables.

For the batches labelled "date codes needed", I haven't got any loudspeaker or transformer date codes, or (gold dust) the 4-digit inkstamp on the metal chassis, which is usually only visible when out of the wooden cab.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.This means that these 2 amp types can only be treated together for dates or production quantities when, as in this study, the serial number is all we have to go on.(Fender did this chassis-sharing thing in earlier years, with the same implications for guessing quantities, as noted by Greg Gagaliano.) I estimate about 5500 were made in total.One run of Princeton Reverb II serial numbers seems to stretch from 1984 to 1986 with just a few from 1987, yes 1987, when some 220V models were still being shipped to Sweden and the UK.