Friday, July 2, 2010

How to read potentiometer codes.

You can sometimes get help in finding the age of a guitar by reading the potentiometer (volume and tone pots) codes. After World War II there usually is a six or seven digit number on the pot that tells you the company,year and week it was made. Although many guitar makers purchased pots in such bulk that pots are sometimes years older than the guitar,it can help to give a window of possibility.
106=  Allen-Bradley Corp.
134= CentraLab
137= CTS
140= Clarostat
220= Jensen
304= Stackpole
328= Utah/Oxford
381 = Bourns
465= Oxford
In a six number code the fourth number is the last number of the year and the fifth and sixth numbers the month. In a seven number code the fourth and fifth number indicate the year and the sixth and seventh,the month. Volume and tone pots do get replaced,of course,but these codes can help in cracking the sometimes baffling birth date of your guitar.
 
Here's one that indicates a CTS pot made in the 27th week of 1978

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