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ID these tubes for me!

Discussion in 'Amp Tech Center' started by schmee, Oct 30, 2020.

  1. schmee

    schmee Doctor of Teleocity Silver Supporter

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    Still going through my tube stash and selling. I have some of these RCA branded 12AX7's. Made in Gr Brittain. They dont have the typical octagonal surround around the tube number, so I figure they are Mullard or Amperex or RFT ...? I have some long plate Mullards and Bugle boy. But nothing like these. I cant find any info on them. Any ideas?
    -short plate
    -Black plate
    -large 0 getter
    -The plates are a bit airfoil shaped which is also very weird. I made a sketch that's roughly the same.
    [​IMG]
     
  2. Wally

    Wally Telefied Ad Free Member

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    My WAG.....these are Cold war era rebranded tubes that circumvented the laws that did not allow direct purchase by U.S. companies of such items from the Soviet Union/Communist bloc. ???? I could be wrong, but those don’t look like a Made in Great Britain tube at first glance.
     
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  3. slider313

    slider313 Tele-Afflicted Silver Supporter

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    Those look like RFT made tubes to me.
     
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  4. radiocaster

    radiocaster Poster Extraordinaire

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    If so, they never made ECC83/12AX7 types in the Soviet Union, not even for export (except in the late 80s/early 90s, and those were never branded "RCA"), so they would have to be East German, Polish, Czechoslovak or Hungarian.
     
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  5. schmee

    schmee Doctor of Teleocity Silver Supporter

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    They say made in Great Britain on them.
     
  6. Wally

    Wally Telefied Ad Free Member

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    rebranding was commonly done in the Cold War era after U.S. production lagged behind the U.S. military’s needs. That tube looks like no English tube I have ever seen. But, as always, I could be incorrect. Are there any codes anywhere on the tube? fwiw, misleading printing on a tube is easily done, and such was done to do an end run around the import restrictions of those Cold War days.
    etched codes are another matter and are more believable.
    That said, I will plead ignorance 9n the identification of these tubes. They certainly do not look like any Russian tube from the era either, one of which was a sub for the 12AX7 as long as the heater filament voltage was 6 volts as opposed to 12 since the heater filaments in the Russian tube was internally wired in parallel.
     
  7. schmee

    schmee Doctor of Teleocity Silver Supporter

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    Yeah, I've never heard of rebranding "country of manufacture" though. Rebranding company logo or even tube number was common for a long time. Some even have two logos on them. Anyway, thanks for looking.
     
  8. schmee

    schmee Doctor of Teleocity Silver Supporter

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    WINNER! We have a winner. RFT they are. These tubes still have a trace of that yellow U shape visible amongst the RCA logo.
    Thanks Slider313 !
    RFT:
    [​IMG]
     
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  9. Jon Snell

    Jon Snell Tele-Holic

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    UK valves were always known by their UK identity back in the 60s and 70s when I used a lot of them; ECC83 never 12AX7 because that was for the North American market.
    Even Mazda, which relabled Brimar and Mullard valves used the UK icentity not the American.
    I have seen quite a lot of "Mullard" branded knockoffs on fleabay. Not to say they are not good at all, in fact some are superior to others.
     
  10. Wally

    Wally Telefied Ad Free Member

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    RFT...East Germany...part of the Soviet bloc. These tubes were illegal to import to the U.S., and these Rebranded tubes were brought through Great Britain to the US. in order to circumvent those laws.
    Supposedly these tubes have a good rep especially among Marshall players. Kind of pricey...
    http://www.nosvacuumtubes.net/product/rft-12ax7/
     
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  11. schmee

    schmee Doctor of Teleocity Silver Supporter

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    :eek: I better go raise my price!
     
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  12. Wally

    Wally Telefied Ad Free Member

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    lol...that is what I think when I see what is being asked for some of the tubes I have. However, I do not have the tube tester/s upon which I can base the justification for such pricing....other than actual amplifiers.
     
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