Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: Locrian99 on September 28, 2024, 01:11:06 am
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Hello,
I just picked up a 72 bassman 50. OT, choke both check out to the date stamp of Feb 17, 72. But the PT is stamped strangely and just wanting to double check its original. Stamped as followed
J022814
606 0572 7
CSA TEST
Thanks
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Hi Lochrian
022814 is a power transformer for BF and SF Bassman, from what I have read, based on 125P7D = 022814
The 125 number scheme is Leo's (pre CBS) and the 6 digit number is the CBS scheme.
Regards
Mirek
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Read in the link at the end
TRANSFORMER DATE CODES:
Another way to get a close estimate of when your amp was made is to read the codes on the transformers. Most post tweed Fenders had trannys manufactured by Schumacher.
They used a code like this: 606 – 645
The date is in the last three digits, after the 606 – . 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. Now if it’s a blackface amp, it’s a safe bet that 6 means 1966. If it’s a silverface amp, that 6 indicates 1976.
This code can be found on the power transformer, output transformer, choke, and reverb transformer. They are all usually within a few months of each other. Use the latest one to give you a good idea of when it was made. For example, if your silverface super reverb has transformer codes all from 1974, it was made in 1974! Let’s say the weeks are 27, 29, 33, 41. Based on the last number (45), it’s safe to say it was made in late 1974.
Many silverface and some blackface amps have the exact week, month and year stamped insie the chassis.
https://vintagefenderamprepair.com/blogs/information/fender-date-codes#:~:text=TRANSFORMER%20DATE%20CODES%3A&text=The%20date%20is%20in%20the,1966%20or%201976%2C%20week%2045.
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Whats throwing me off is the 3 digits after the 606 is 4. Thr choke for instance reads 501. Makes sense for an amp built feb 17th 72. 50th week of 71. Saying 0572 did they change the pt code to show the decade? And every example ive found looking online with the 4 digit code and the 7 just off to the side says 0572. This could work for feb 72 built amp if the 7 is representing the decade, just weird that every example coded this way is week 5 72.