EIA codes...learn to love them!

Discussion in 'Tube Audio' started by Sam Cogley, Jan 26, 2013.

  1. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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    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: Jan 27, 2013
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  2. bobabode

    bobabode AK Subscriber Subscriber

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    Thanks, Sam. :yes:
     
  3. GordonW

    GordonW Speakerfixer Subscriber

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  4. guitbanger

    guitbanger Active Member

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    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
     
  5. Kegger

    Kegger Anything can be S "MODed" Super Mod Subscriber

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    Good info, maybe we can make a sticky with this and add more good info..
     
  6. guitbanger

    guitbanger Active Member

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    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.
     
  7. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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    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: Jan 26, 2013
  8. Tom Bavis

    Tom Bavis Audiophool Subscriber

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    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.
     
  9. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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    The EIA link doesn't do much. For instance, RCA's 274 comes back with "Harris Semiconductor" and nothing else.
     
  10. griffithds

    griffithds Active Member

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    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: Jan 26, 2013
  11. goldleaf

    goldleaf Super Member

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    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.
     
  12. Tom Bavis

    Tom Bavis Audiophool Subscriber

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    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.
     
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  13. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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    Before WWII, and even immediately after, there were a LOT of smaller tube manufacturers. It makes tracking down the early stuff much harder.
     
  14. mech986

    mech986 Text ↓ optional Posts:>18,000 Subscriber

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    Thanks for this thread, agree it should be a sticky.
     
  15. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    +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.
     
  16. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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  17. Sam Cogley

    Sam Cogley Last of the Time Lords Subscriber

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

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

    Sam Cogley Last of the Time Lords Subscriber

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    Two years later, I think this thread needs a bump.
     
  19. toxcrusadr

    toxcrusadr AK Subscriber Subscriber

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    Yes, it should be a Sticky.
     
  20. Tom Bavis

    Tom Bavis Audiophool Subscriber

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    EIA site has disappeared, but I added a 1994 code list.
     

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