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How To Date Pots?
Posted: Mon Nov 23, 2015 1:49 pm
by spongebob
I've read a lot of 'basses for sale' ads when they mention the build date of the bass, and also the age of the pots.
Out of interest, where can you do this? I know the Ric site gives the serial decoder, but is there anywhere where we can trace the age of other (numbered) parts?
Re: How To Date Pots?
Posted: Mon Nov 23, 2015 4:33 pm
by Kopfjaeger
Pot casings have a date code stamped on them. Different vintages have the date code either on the side of the case or on the backside.
Sepp
Re: How To Date Pots?
Posted: Mon Nov 23, 2015 9:27 pm
by clementc3
A helpful explanation is here:
http://www.guitarhq.com/pots.html
An excerpt:
How the Source-Date Code Works.
The source-date code on a pot is a 6 or 7 digit code impressed into the casing of the potentiometer. For speakers this code can be 5, 6, 7 or 8 digits long, and it's ink-stamped or paint-stamped on the "bell housing" of the speaker.
In either case, the code works the same. The first 3 digits on a pot, or the first 2, 3 or 4 digits on a speaker are the source or manufacturer code.
The remaining 3 or 4 digits are the date code. In 3 digit dates code, the 1st digit is the last digit of the year. On 4 digits date codes, the 1st and 2nd digits are the last two digits of the year. In either case, the remaining 2 digits are the week of manufacture (01 to 52). With this in mind, remember if the last two digits of the source-date code are greater than 52, you're not looking at the source-date code!
Here is an online "pot dater" - enter the code and it will tell you the manufacturer and date:
http://www.guitardaterproject.org/potcodereader.aspx
Re: How To Date Pots?
Posted: Tue Nov 24, 2015 6:46 am
by spongebob
Thanks guys.
I don't think I took a picture of the right number? My Luthier had it apart, so I wanted to photograph the internals -
Re: How To Date Pots?
Posted: Tue Nov 24, 2015 10:09 am
by clementc3
Your photo got most of the right number - I think the number you are looking for is the one that begins "137", which is the code for Chicago Telephone Supply (CTS), and a pretty common code (they must have made a lot of the pots that were used by instrument manufacturers).
I see three of the next (probably) four numbers, "734" - I think there is a fourth number underneath the yellow wire. My uninformed guess is that the pot was made by CTS in the forty-something-eth week of 1973. More knowledgeable forum members, please chime in!
Re: How To Date Pots?
Posted: Tue Nov 24, 2015 11:40 am
by aceonbass
Clement, you are correct. The four digit code after "137" is the date code. I suspect that the yellow vinyl insulated wire is not original though.
Re: How To Date Pots?
Posted: Tue Nov 24, 2015 1:42 pm
by spongebob
That's excellent info - many thanks chaps.
Re: How To Date Pots?
Posted: Tue Dec 01, 2015 10:51 am
by RickyBubba
I need to get out more often, didn't know they were MIM also!
Re: How To Date Pots?
Posted: Fri Dec 04, 2015 8:32 am
by spongebob
Everyday's a school-day!