I started to investigate the world of pre-CBS Fender amplifiers.
There was a lot more variety than I had ever experienced first-hand while playing in bands in the mid-to-late ‘60s.
The tube chart date code works like this: the first letter indicates the year and the second letter indicates the month.
So if your blackface amp has a date code stamp of OB, it was made in 1965/February.
I have presented my amps in rough chronological order by era.
In the early ‘60s, Jensen changed to more rugged ceramic magnet speakers.Fender adopted a two-letter date-coding system for its amplifiers.Starting in 1951, the tube chart of the amp (and sometimes the speakers and chassis) were stamped with two letters: Year/Month.I’ve done minor work on a few of the amps, like having original speakers reconed and changing out frayed power cords.Some of the amps in my collection have their original tubes, capacitors and speakers; on some they have been replaced.The first of the three digits tells us the last digit of the year (unfortunately not decade specific) and the last two numbers tell us the week.In the above example, the transformer was made in either 1966 or 1976, week 45.There are some exceptions and some overlap, but the general idea is this: Tweeds (early 50’s to very early 60s), Browns (1960 – 1962), Blondes (1962 – 1963), Blackface (1963 – 1967), and Silverface (1967 – 1981).Up until the end of the blackface era (1967), all amps left the factory with a tube chart that had a two letter date code stamped on it.Many silverface and some blackface amps have the exact week, month and year stamped insie the chassis.My first Fender amp was a 1965 blackface Deluxe, purchased new for 9 at The Music Manor in Ft. I couldn’t scrape together the extra to get the Deluxe Reverb upgrade, but I figured I didn’t need reverb anyway.