The Vintage Guitar News and Views ,Greg's Guitars.

This month we will look at some of the Fender amp facts that may be of use to you in determining the date your amp may have been produced and the type or style circuit it has.

On American made vintage guitars and gear, the pots and speakers provide an excellent opportunity to date a piece of equipment by referencing their "source-date code".

The source-date code found on pots and speakers gives the manufacturer and date (roughly) when the components were made. It may have been some time before the part was installed at the factory, but it still provides a good approximation of when the gear was made. This is especially helpful on (less popular) gear that doesn`t have reliable serial#`s or other information to date them.

The source-date code will signify the earliest possible date that the instrument or amp could have been made. This isn't going to be exact, but it will give you a "ball-park" age. And remember, even the dates indicated by the pots aren't that exact. For example, if you buy a brand new CTS pot today, they are dated a month or two in advance! I don't know the reason for this, but it's worth mentioning.

The source-date codes are under the framework of the "Electronic Industries Association", which is a non-profit organization representing the manufacturers of electronic parts. The EIA source-date code is a numeric code, assigned and registered by the EIA. It can be stamped or marked on any product to identify the production source (vendor) and date of manufacturer. Source-date codes have been published by the EIA since 1924. The EIA can be contacted via mail: Electronics Industries Association, 2001 Pennsylvania Ave NW, Washington, D.C. 20006.

Consideration and exceptions:
• Source-date codes weren't an industry standard until after WWII. But I have seen them used on Stackpole pots on electric National guitars as early as 1935. The first time date-source codes were published was 1924, so I guess you could see them as early as the late 1920's.
• Most Fenders from 1966 to 1969 have 1966 dated CTS pots. Apparently CBS/Fender bought a large stock of pots in 1966 that lasted till 1969.
• On popular Fender models, the pot date can be very close to the actual date of the instrument. On less popular Fender instruments, such as LapSteels, pots can be as much as two years earlier than the actual date of the instrument.
• Gibson didn't start using pots with source-date codes till 1953 or 1954.

Originality.

Of course this all assumes the pot or speaker is original. You have to make that call. I would suggest checking the solder joints - are they clean? Are the wires of the right era (cloth insulation for older stuff)? If so, you can check the pot or speaker for the source-date code, and determine an approximate age from that.

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!

Also it's worth mentioning:

• Sometimes there is a space or hyphen between the manufacturer code and the year/week code.
• 3 digit date codes were used in the 1940's and 1950's. Stackpole for example converted from three to four digit date codes in late 1959.
• 4 digit date codes were used in the 1960's and later (this makes determining the year much simpler)
• On 3 digit date codes, you have to "guess" the decade of the pot or speaker. Usually this isn't too difficult.
Like with many mass produced items their is a certain amount of irregularities and although nothing can be positively absolute this system does provide a reasonable date and circuit for Fender amps.
Not meaning to be all inclusive by any means this article skims some of the facts about Fender amps and hopefully provides information and answers to some questions you may have , in a future installment we will discuss some modifications on Fender amps ( any amp actually) that you may be wanting to do and what modifications I believe you really do not need to do, of course this is just my vintage guitar (and amp) news and view. So untill next time ,may all your friends stay true ,all your days be memorable and all your riffs be killer.