Everyone's Favorite Game-Name That Tube!

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by homebrewer99, Feb 7, 2008.


  1. homebrewer99

    homebrewer99 Member

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    Hello All-

    I stumbled across a few unknown tubes and would love some help ID'ing them. Here they are...

    Unknown 6L6GC, USA made with octagonal logo:
    [​IMG]
    [​IMG]

    Unknown 12AX7s:
    [​IMG]
    [​IMG]

    Any help would be appreciated. Thanks for playing!!
     
  2. Swarty

    Swarty Member

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    The 6L6s are black plate RCAs. Just guesses on the preamp tubes, but I'll say the top left is RCA, top right is Tungsol, bottom left is EI and bottom right is Chinese.
     
  3. evacuated

    evacuated Member

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    The 12ax7's look like RCA on the left and possibly a Sylvania or a Raytheon on the right.
     
  4. Anywho

    Anywho Member

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    Westinghouse on the right.
     
  5. Blue Strat

    Blue Strat Member

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    Any etching on the glass of the 12AX7s? GEs would use stencil type lettering with a series of dots, RCAs would have "12AX7" inside a "flattened octagon" near the top.
     
  6. homebrewer99

    homebrewer99 Member

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    BlueStrat-

    No etching that I can see on the 12ax7s. One has a faint "12AX7" marking near the top of the tube in gray/black writing. I will look closer when I get back from work.

    To all:
    Thanks so much for the help!
     
  7. Bonenut

    Bonenut Member

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    Tung-Sol or Raytheon on the left, Sylvania or Raytheon on the right. Just a quick guess though. I'll have to compare those pics to the actual tubes later.
     
  8. Lonely Raven

    Lonely Raven Member

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    Those are some great photos! I tried to play this game with people a couple years ago, and nobody seemed willing. So I just wound up doing some neat photography.

    [​IMG]


    [​IMG]

    I think I can see some electrons moving in that second one! :)
     
  9. homebrewer99

    homebrewer99 Member

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    LonelyRaven-

    That second picture is incredible!! And yes, I am glad to have so many participants in my thread.

    As far as your tube ID, im gonna go out on a limb here and guess its a Telefunken...:)
     
  10. Blue Strat

    Blue Strat Member

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    Good guess, but keep in mind that Telefunken also bought and relabeled tubes from other companies like Mullard, RFT, etc.
     
  11. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I've seen others call those Westinghouse, too. I think Westinghouse re-labeled Sylvania-made tubes. What I'm saying is that the 12AX7 on the right is a Sylvania short gray-plate, with square-getter, made in 1957. Sylvania made a black plate version that I really enjoy, just the year before. And the next year ('58), they went to long gray-plate.

    The short gray-plate/square-getter Sylvania is an early-breakup 12AX7, somewhat like RFT's ECC83, but with better clarity. Note the pointy tip of the glass - that's another characteristic of Sylvania's mid-'50s short-plate 12AX7s. Also note that the plates look like those on a 5751. Its a fine tube.

    - Thom
     
  12. rockon1

    rockon1 Member

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    Yes like Thom said the one on the right is a rebranded Sylvania more than likely. Ive got about 30 of these some labeled Westinghouse. I think its unlikely Sylvania would relabel Westinghouse and besides the 12AX7 ecthing looks like other Sylvania's I have. Bob


    [​IMG]
     
  13. rockon1

    rockon1 Member

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    Or not... Been a while since Ive looked at my collection of these tubes. Iremember there being a condtradiction with these tubes. I also have estinghouse labeled ones that bear (from my understanding) a more 'Westinghouse" type of ecthings with small dots around the "12AX7".... Im wondering if perhaps Westinghouse acqiured the tooling for the tube later from Sylvania or something? confused still on this one. Bob


    [​IMG]
     
  14. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Got a photo of the tip of the glass, Bob? Is it elongated/pointy? Just curious...

    - T
     
  15. marty pollard

    marty pollard Member

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    Did Westinghouse make any of their own tubes or were they all rebrands?

    I ask because one of my favorite ax7s was my only Westinghouse until it started to hum but at the same time the two Sylvanias I tried were both too shrill for my tastes.

    I know it wasn't my imagination.
     
  16. Blue Strat

    Blue Strat Member

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    They definitely made some of their own until at least the early '60s. Their 6V6GT is unique.
     
  17. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Yes, Westinghouse did make some of their own tubes. I don't know if this 12AX7 was one of them, but if you've noted a definite sonic difference between the visually identical Sylvania and Westinghouse versions, then that would support the theory that Westinghouse really did make their own 12AX7.

    Bob - have you also noted a sonic difference between the Sylvania and Westinghouse versions?

    - Thom
     
  18. rockon1

    rockon1 Member

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    No not between these. I just A/B'd a few of each to refresh my memory and they all have the same basic characteristics-smooth rounded top end,early break up. The glass tips are all similar -elongated/pointy. From what I remember Westinghouse used dots around the etched 12AX7 ,yes? Thats the only difference between them visually and sonically as far as I can tell-The etchings look correct for each brand. Bob
     
  19. Free

    Free Member

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    [​IMG]


    LOL... I can see a quark!
     
  20. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    Yes, Westinghouse had the small dots (smaller than GE). From what you described, I'd say that Westinghouse re-branded the Sylvanias. The glass tip is unique enough to set these apart from other manufacturers. Of course, if Westinghouse purchased the Sylvania materials and machines, from 1958, that'd make sense too, but it is much less likely.

    Thanks for reporting back, Bob.

    - Thom
     

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