Return to the Main Index. Sometimes there just isn't enough information on electric instruments and amps to allow them to be properely dated.
And many people ask me to try and determine the year of their old amplifier, or to help them with the year of their older off-brand electric guitar.
Since I primarily collect amps by Fender, and guitars by Gibson, Fender, Martin, National, Epiphone, Gretsch and Rickenbacker, I really can't help them with these other less popular brands. As you have probably noticed, there is plenty of information here to help date the brands that I am interested in.
But where does that leave everyone else? Well I'm not one to leave you out in the informational cold, so here's something that I use quite often in dating amplifiers and electric guitars.
It's called the "source-date code", and it can help determine the approximate age of an electric instrument by the date its components were manufactured. Source-Date Codes On American made vintage 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. 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!
It's worth mentioning since a lot of people rely on pot dates. That said, it's not uncommon for pot manufacturers to post date pots anywhere from a few weeks to as much as 18 months.
The standard today is no more than 18 months, but back in the s and s, who knows? Some large parts distributors would even return parts if the date code was "expired" and want "fresh" parts in return. This seems silly, as we're talking about electronic parts not eggs. But if you think about it, parts like electrolytic cacpacitors, this could be an issue.
Then the parts maker like CTS would have to eat the returned inventory, or sell it off to someone that didn't care about date codes, and probably at a discounted amount. What I'm saying is that pot and capacitory date codes are not a reliable indicator of guitar build dates.
Though they are one piece of the puzzle and something to consider, don't put too much faith into a pot date. 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. 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 The EIA can be contacted via mail: 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 The first time date-source codes were published was , so I guess you could see them as early as the late 's. Most Fenders from to have dated CTS pots.
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 or 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 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: Stackpole for example converted from three to four digit date codes in late On 3 digit date codes, you have to "guess" the decade of the pot or speaker. Usually this isn't too difficult. Pots used by Fender. The pots on the left and right are Stackpole pots manufacture Note the different position of the markings, even on pots from the same maker. The source-date code on a speaker.
In this case, the speaker is made by Rola in the 9th week of The decade, though not directly shown by the source-date code, was easily determined because this particular amp was only made during the s. Note the font style of the source-date code number always seems to be the same, for all speaker manufacturers.
Jensen speaker made in the 41st week of Here are the most common pot manufacturers the first 3 digits of the source-date code: