Potentiometer Codes

Electric guitars can be dated by the coded date located on either the potentiometer sides or back. They should be used in conjunction with other identifying factors such as serial and model numbers to help to correctly identify your instrument. ’47 Brand Chicago Bears Infant Basic Team Logo Adjustable Hat – Navy Blue,Detroit Lions Crazy Horse Leather Belt – Brown,Women’s Buffalo Bills Black Cameo Knit Leggings Cheap Jerseys from china.Women’s Atlanta Falcons Klew Black Gradient Leggings,Women’s Seattle Seahawks Russell Wilson Nike Gray Game Jersey cheap nfl jerseys

Stamped on every potentiometer (volume and tone pots) is a six- or seven-digit source code that tells who made the pot, as well as the week and the year. The source dating code is an element of standardization that is administered by the Electronics Industries Alliance (EIA). The EIA assigns each manufacturer a three-digit code (there are some with one, two or four digits).

When dating an instrument by the ‘pot code’ keep two things in mind:

1:The potentiometers must be original to the piece (new solder, or a date code that is off by ten or more years is a good giveaway to spot replacement pots).

2:The pot code only indicates when the potentiometer was built. If the pot is an original to the guitar, it indicates a date before which the guitar could not have been built – so it’s always a good idea to have extra reference material around. For example, a pot code dated the 50th week of 1952 probably means the instrument may not have been finished until 1953.

Finally, a word of caution: This method applies only to American made pots and not all potentiometer manufacturers subscribed to the EIA source code date. If the code does not fit the criteria on this page, you will have to investigate further on the web to find
the manufacturer of that model pot to help  date your guitar.

If you have an instrument that you suspect predates WWII don’t be alarmed if you can’t use the pots to aid you in instrument  identification. Codes on pots didn’t start appearing until after WWII.

Codes have the following configuration mmmyww or mmmyyww

The first three digits mmm indicate the maker of the pot.
Among the most common are the following:

106 Allen-Bradley Corporation
134 Centralab
137 CTS, (Chicago Telephone Supply)
140 Clarostat
220 Jensen
304 Stackpole
328 Utah / Oxford
381 Bourns Networks
465 Oxford

The 4th digit y in a 6-digit mmmyww code corresponds to the last digit of the year of manufacture. Pot makers used a 6-digit code prior to 1961 and a 7-digit mmmyyww code from 1961 onwards. Some other companies however continued with a 6-digit mmmyww code.

The 4th and 5th digits yy in a 7-digit mmmyyww code correspond to the last 2 digits of the year of manufacture.

The final 2-digits ww in a 6-digit mmmyww code or a 7-digit mmmyyww code correspond to the week of the year in which the pot was made. Note: A series of numbers greater than 53 can not be a week dating code as it would be longer than the weeks in a year.


304-6320 was made by Stackpole in the 20th week of 1963

1377633 was made by CTS in the 33rd week of 1976

304731 was made by Stackpole in the 31st week of either 1947 or 1957