Pot codes: the earliest an instrument could have been built
Most electric guitars carry potentiometers stamped with a short number. It names the maker of the pot and the week it was made. The guitar cannot be older than its pots.
Six or seven digits. Spaces are ignored.
Reading
Type a code to see the maker, the year or years it allows, and the week.
Use this with a serial number. The decoder drops any reading earlier than the pot.
Makers on the list
Sort by any column. Select a code to carry it to the decoder.
| Note | Example | ||||
|---|---|---|---|---|---|
| 137 | CTS (Chicago Telephone Supply) | 1930s to present | Commonly reported | Very common on guitars. Commonly reported by collectors. | 137 52 05 |
| 304 | Centralab | 1930s to 1980s | Commonly reported | Commonly reported by collectors. | 304 59 12 |
| 134 | Stackpole | 1930s to 1980s | Reported, verify | Reported by collectors; verify against the EIA list. | 134 61 20 |
| 140 | Clarostat | 1930s to 1960s | Reported, verify | Reported by collectors; verify against the EIA list. | 140 58 07 |
| 328 | Switchcraft | 1930s to present | Reported, verify | Reported by collectors; verify against the EIA list. | 328 62 03 |
How to read the code
- 6 digits: manufacturer, then year digit, then week. The decade is not stored, so use the era of the instrument.
- 7 digits: manufacturer, then year, then week. Two-digit year.
Example: 137 52 05 reads as maker 137, year 52, week 5. With six digits the year is one digit, so 137 2 05 could be 1952 or 1962 or 1972, and the decoder lists each.
What it cannot tell you
A pot code gives the earliest the instrument could have been built. Pots were stocked and swapped, so it is a floor for the date, not proof. The manufacturer list is a partial subset and marked by confidence.
Pots get swapped in repairs, so a late code on an otherwise early guitar points to a repair, not a later build. The reverse is the useful case: a pot dated 1966 rules out a 1963 build. Read the full guide to dating by pots.