Date codes for Tung Sol Tubes

[jmcox00]

Does anyone know how to interpret Tung Sol tube dates codes? I believe I understand the reading of numerical codes (i.e., 3226441-3 would be as follows: with 322 being Tung Sol's id, then 64 would signify 1964 and 41 would be 41st week of that year. 3 . . .I'm not sure what that signifies). I have a date code tube that has a couple letters in the code . . . .322RC-3. On that one I can't guess. ????

[Dr Morbius]

I'd like to know myself.       Anybody?

[Audible Nectar]

My understanding is that once they got into the "letter codes" that it became a mystery, as the "decoder" sheets never got passed down. I have seen this question asked on audio forums before and this was the explanation given. Maybe someone out there has a better answer, but that's the best I can do as I know it.

[jmcox00]

Yep, I searched some other forums also and no one seems to know . . . .

[easyone]

I have several older Tung-Sol tubes and it was driving me crazy that "no one" seemed to know what the lettered date codes signified. I called a Tung-Sol technician at the Tung-Sol headquarters, and apparently Tung-Sol was bought out in 1967, and then changed hands a few more times since then. The lettered date codes - 322DR3 as an example - would have been before 1967, but that is all he knew about it. "The date codes were not handed down" is what he told me. The tube I am looking at right now is a 6SL7GT which started production in the early 1950's according to the technician. That means it is from somewhere between the early 50's and 1967. The 322 = Tung-Sol and the DR3 is the unknown date. Any guesses on the DR3? I would venture to guess the "D" is the year and the "R3" a more specific time of that particular year. 

 

I guess we will never know unless an old Tung-Sol employee reads one of the hundreds of posts on many different tube forums. C'est la vie!

[dirtmudd]

On 1/10/2018 at 3:14 PM, easyone said:

I have several older Tung-Sol tubes and it was driving me crazy that "no one" seemed to know what the lettered date codes signified. I called a Tung-Sol technician at the Tung-Sol headquarters, and apparently Tung-Sol was bought out in 1967, and then changed hands a few more times since then. The lettered date codes - 322DR3 as an example - would have been before 1967, but that is all he knew about it. "The date codes were not handed down" is what he told me. The tube I am looking at right now is a 6SL7GT which started production in the early 1950's according to the technician. That means it is from somewhere between the early 50's and 1967. The 322 = Tung-Sol and the DR3 is the unknown date. Any guesses on the DR3? I would venture to guess the "D" is the year and the "R3" a more specific time of that particular year. 

 

I guess we will never know unless an old Tung-Sol employee reads one of the hundreds of posts on many different tube forums. C'est la vie!

http://www.triodeel.com/eiacode.htm

 

https://www.tubemuseum.org/SearchResults.asp?Cat=30

 

http://www.tubemaze.info/deciphering-european-tube-date-codes/