Pots And Harnesses

This is a brief outline of the various pots and caps and wiring used by Gibson. This is not a complete summary but is a good start for the beginner. The basic companies Gibson used were IRC ,CTS , Central Lab. IRC used (615) code to begin the sequence of numbers on the pot case . Central Lab used ( 134 )and CTS used (137) codes.  The way to ready a pot code is as follows . There are several scenarios.

IRC always began with 615 xxxxx  354 . The x’s stood for stock numbers the last three numbers were the year and the week. here is example : 615 34657 334  this is a  IRC pots 1953 and the week is 34th week .

CTS  always started with 137 xxx or 137 xxxx  . The first x or first two were the year the last two x’s were the weeks.  Here is an example 137828     8 represents the year 1958 and week 28th week.  In second example :  1376828  68 represents 1968 and 28 the 28th week .

Central Lab always begins with 134 xxx or 134 xxxx. first example 134521 this dates the pot to 1955 and the 21st week . the second example 1346232 show a 1962 pot from the 32 week.

Remember this that pots can  pre-date a instrument year but never post date it . It was common to have pots 6 month earlier than an instrument but an exact cut off time is impossible to nail down. Usually the earlier the instrument the closer the pot dates are to the instrument manufacturing date. As the companies grew they bought more inventory and pots sometimes were mixed or lying around for a period of time before they were used. In the extreme instance of Fender Guitars in 1966 to cut costs Fender purchased enough pots to last the company for 5 years and so they are found in guitars from 1966-1971

Switches were made by the Switchcraft company and still are to this date . The early switches do not bear the company’s name. but by 1961 all switchcraft switches bear the company name stamped into the switch. Most were three way switches but they also had 5 way switches.

The caps are a very important part of the harness but i would need several full pages to dive into them and their variations . I Will list a few common ones but it is by no means a complete list. The earliest Gibson caps were made by Cornell Dublier or (cd). they were know as grey tigers ( the name found on many ) and were used in hollow bodies and solid body guitars. They were .022 @ 400v . by 1956 they has switched to the Sprague Company. The values were the same but the waxed paper grey tiger caps were now replaced by the Sprauge bumble bee it was black plastic shell with multi colored stripes and is probably the most recognized cap in the world for guitars. There were again a few exception but not many. In 1961 the Sprague caps changed again to the black case with two red stripes one  on each end and they were used up until around 1970.

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