EIA codes...learn to love them!

Sam Cogley

Last of the Time Lords
Subscriber
I see lots of "who made this tube?" or "I don't know who made these..." posts. While manufacturers made tubes for each other all the time, it's often easy to figure out who made a particular tube. GE's markings are very distinctive, but several manufacturers (most notably Tung-Sol) used an octagon very much like RCAs. In these cases, there's usually a three-digit number printed with the markings. (In some more rare instances, it's a four-digit code)

Amperex (US production) = 111
GE = 188
CBS/Hytron = 210
RCA = 274
Raytheon = 280
Sylvania = 312
Tung-Sol = 322
Western Electric = 336
Westinghouse = 337

If you find something odd, usually a quick Google search will turn up who that EIA code belongs to. Here's one page that's a good reference: http://www.triodeel.com/eiacode.htm

The codes aren't always present, but when they are, there's no need to wonder who made your tube!
 
Last edited:
I have a complete eia production source code booklet from 1961. Came in a Sams folder. Set 537 dated July 1961. That's how I finally managed to id the mysterious 789 code that appeared on so many of my beloved Eico's! lol
 
I don't have a scanner or I'd post the whole thing. If any of you guys would be willing...pm me. I'd love for this to be available to everyone.
 
I'd be happy to scan it. Shoot me a PM and I'll give you my address. Let me double-check my Sams box to make sure I don't have it first.

Who had the 789 code, BTW?
 
Last edited:
I have a few of the EIA lists ('57, '59) on my site already: http://www.audiophool.com/Techno.html - would be glad to add this one. I may have the '46 RMA list too... that was before they changed their name to EIA. And the EIA has a current site where you can enter an EIA code and they'll show the last company and previous companies that used it. Of COURSE there's a link on my site.
 
The EIA link doesn't do much. For instance, RCA's 274 comes back with "Harris Semiconductor" and nothing else.
 
I have several Tung-Sol 6SN7GT V-231's (IEA code 322) that are without a doubt Raytheons. To see one, go to ebay #200872964171. So know your tubes, and don't rely on just codes.
Regards,
Don
 
Last edited:
Appreciate the info. I have been stumped several times, looking at tubes with different stamps that look suspiciously similar. I wish there was a photo facts site for construction details on the more common tubes like the AX series and output power tubes. There are some very odd looking power triodes out there, turning up on ebay with minimal or no markings.
 
The EIA link doesn't do much. For instance, RCA's 274 comes back with "Harris Semiconductor" and nothing else.

Harris bought out GE's Semiconductor division, which had previously bought RCA's remains, in 1988. 280 is still Raytheon, 188 is still GE, 337 still Westinghouse, 312 is Sylvania from 1945-1977, Philips ECG after that. 322 is Wagner Electric, which merged with Tung-Sol in 1966. So yeah, not always straightforward.
 
Before WWII, and even immediately after, there were a LOT of smaller tube manufacturers. It makes tracking down the early stuff much harder.
 
+1 on the Sticky.

I made a big speaker driver manuf. code list awhile back and posted it in Speakers, but it scrolled off almost unnoticed. Considering how often this comes up, I think sticky is the way to go.
 
I don't have a scanner or I'd post the whole thing. If any of you guys would be willing...pm me. I'd love for this to be available to everyone.

I'll drop it back in the mail tomorrow. Thanks!

I have a few of the EIA lists ('57, '59) on my site already: http://www.audiophool.com/Techno.html - would be glad to add this one. I may have the '46 RMA list too... that was before they changed their name to EIA. And the EIA has a current site where you can enter an EIA code and they'll show the last company and previous companies that used it. Of COURSE there's a link on my site.

Thanks to guitbanger and Tom, the Sams 1961 EIA code list is now available: http://www.audiophool.com/Misc/EIAcodes1961.pdf
 
Back
Top Bottom