Tube Question, Tung-Sol 12AY7

Discussion in 'Amps and Cabs' started by HeavyCream, Aug 30, 2019.

  1. HeavyCream

    HeavyCream Member

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    I got a Frenzel FM-DP1 Preamp in the mail today, wasn’t supposed to arrive until Tuesday (score #1 :cool:). The first thing I always do is check the glass to see if the tube fairy left me a surprise.
    V2, Tung-Sol 12AY7!? (Score #2 :dude). What could possibly be in V1?...
    JJ :(. Oh well, can’t win em all.

    I’m thinking it’s from the 50’s. Square getter. The thing is, I’m not sure it’s really a Tung-Sol. I think it may have actually been made by GE. The “12AY7” lettering looks the same as my GE (not that that’s conclusive evidence). I’ve read GE made AY7s for a lot of other brands.

    There’s not much info on these. I did find a Tung-Sol labeled 12AX7 that looks very similar but the “12***” lettering was the type in a rectangular octagon (not sure that’s important).

    Anyway, I’m willing to bet dollars to donuts at least one of you guys can help me ID this little gem.


    [​IMG] [​IMG] [​IMG]
     
    Last edited: Aug 31, 2019
  2. HotBluePlates

    HotBluePlates Member

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    See how the rods supporting the grid are at 90-degree to the axis of the plate? While inconclusive on its own (a Hitachi in a recent thread had similar), I associate that structure with G.E., as possibly all of the U.S.-made tubes I've seen built like that were G.E. tubes.

    And they also had the stencil-like type number on the glass, as yours does. That's typically a G.E. feature.

    The nail in the coffin is the "pattern of dots" below the type number. Somewhere I have saved the method for translating that dot-pattern to date of manufacture. It was posted on this site by @Timbre Wolf and @DaveKS IIRC, who noted G.E. and CBS used a dot code (possibly Westinghouse, too?).

    Anyway, I'd be comfortable calling it a G.E. (I could probably find some of my own G.E. 12AY7s, to compare micas & getters to really put it to rest).
     
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  3. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    It looks like genuine Tung-Sol print... on a GE tube. That appears to me like a late-'50s GE JG12AY7. The dot etch isn't conclusive in itself, as HBP mentioned, because CBS and Westinghouse used their own dot coding. But the inside structure looks like GE.
     
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  4. Jeff West

    Jeff West Member

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    Yeah, T-S did manufacture their own 12AY7 versions, but large numbers of T-S branded in '50s and '60s were GE made. That one definitely is. Same for earlier box plate versions, grey and black- genuine T-S exist, but many are GE/Ken-Rad.

    @HotBluePlates, if you want GE dot decoding it's here, starting post #11:
    https://www.thegearpage.net/board/index.php?threads/can-someone-id-these-tubes.1759986/

    Without decoding, I'd estimate the one depicted above is late '50s or maybe 1960 or so.

    From a post in 2017 (recycling is easier than writing out again!) with some description of the manufacturing sequence of GE 12AY7s:

    "I think the GE manufacturing sequence included: black boxplates 1949-51, grey boxplates 1951/2-53, then '54-'56 they had small grey plates with a bent rectangular getter ring mounted on a very short stem and usually angled, then late '50s they had small grey plates and a rectangular getter on a longer rod and usually more horizontal. The GE "dots" system first appeared in 1952, and I don't think I've ever seen them on black box plates, but there are definitely grey box plates both with and without the GE sandblasted dots dating code. On the earliest grey box plates there's typically the distinctive GE sandblasted "12AY7" just without any dots, often with "Tung-Sol" or "RCA" screened right on top of it!"
    https://www.thegearpage.net/board/index.php?threads/nos-tung-sol-12ay7.1871799/#post-24995493 #9
     
    Last edited: Aug 31, 2019
  5. HeavyCream

    HeavyCream Member

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    Thank you guys :bow. I felt like it was probably GE but had a hard time making a positive ID. The volume of tube knowledge some of you guys have is astonishing. I’m very late to the party, just trying to learn all I can.

    There’s some great posts in that thread! Bookmarked. I’ll definitely try to decipher the dots later. Of course, Tung-Sol put their stamp right over them :confused:. Pretty sure I can make it out though. I have a couple other GEs I’d like to date as well. Pumped!
     
  6. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I’ll just add that Tung-Sol made the only long-plate 12AY7 that I know of.
     
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  7. Jeff West

    Jeff West Member

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    Yes, and those started around early 1960, maybe even 1959, still with rectangular getter arrangement.

    I really like 12AY7s in some amps where they're called for or suited for, and some of the GEs are really good IMO.
     
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  8. HotBluePlates

    HotBluePlates Member

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  9. mwhy

    mwhy Supporting Member

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    Hey HeavyCream,
    Congrats on the new Frenzel! How are you using it (i.e., recording, in front of a solid state amp, etc.)? Jim makes great gear!

    Marc
     
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  10. HeavyCream

    HeavyCream Member

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    Love it. Going do post a review soon. Been working her out pretty regularly the last couple days. I got it for home/recording.

    I’ve tried a couple different setups. Right now I’m going into a KT-66 power amp via the FX Return on my PV VKII. Sounds killer!
    I also have a 6v6 amp and an el34 amp with fx loops. Tried the 6v6 but not el34 yet.

    I love blending the F and M channels together. Two different sets of gain stages breaking up in parallel is a thing of beauty. The two channels compliment each other nicely.

    The M channel is awesome on its own. It definitely has the low gain classic Marshall thing going on. The F channel is darker than I expected. I haven’t spent as much time with it because M and F/M are so much fun.
     
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