Telefunken 12AX7....without diamond

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Curt, May 3, 2005.


  1. Curt

    Curt Member

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    I just picked up a new unopened Telefunken 12AX7 from an old box of tubes in our metrology dept.
    The lettering is perfect. The question is that it doesn't have the diamond on the bottom of the tube like my other telefunken's have. It say's "Made in Western Germany" and has a QA Q1 on the side.

    Any idea why no diamond?
     
  2. Igneous

    Igneous Supporting Member

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    does it sound good?
     
  3. Blue Strat

    Blue Strat Member

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    Yes, it likely wasn't manufactured by Telefunken. Only an inspection of the internals by a trained eye will yield an answer to this. Photos?
     
  4. Curt

    Curt Member

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    Funny you should ask. A while back, I walked into our Metrology dept. and opened three drawers that looked like they hadn't been opened in ten years. It was like finding buried treasure. I asked the manager what he was going to do with all these "worthless old tubes". He said "he didn't really care what happend to them".
    He asked me if I wanted them. I said "yea, sure, I guess so."
    Brand new, never opened 12AX7, 5751's, Telefunkens, RCA's Mullards, Amperex, Siemens, GE's etc. Not to mention all the new EL84, and 34's and a lot more very valuable power tubes.
    A fellow 23 year old engineers saw me walk in to my office with the large box of tubes. He asked me "what are you going to with all that crap in the box?" I just smiled.
    Anyway..I saved a few tubes.. The rest are gone.
     
  5. drbob1

    drbob1 Silver Supporting Member

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    My sob story, the local tube guy got ill. I told him if he decided to close up shop, call me and I'd give him a fair price for his tubes. Couple of months later, stopped by again: oh yeah, some guys from the city had been by and bought all the useful tubes but I was welcome to the radio stuff that was left...:mad:

    Oh well. Congrats on your score!
     
  6. TheAmpNerd

    TheAmpNerd Member

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    Mike,

    I've come across some of the smooth plate telefunkens
    without the diamond on the bottom. The innards are
    identical to the other telefunkens that I have that are
    the same tube. : )
     
  7. Igneous

    Igneous Supporting Member

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    Ive seen mullard innards in a 'labeled' tele before
     
  8. Blue Strat

    Blue Strat Member

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    Yep, I've seen them too. Also RFTs in Tele "clothing".

    The one mentioned above is actually a Tele without the diamond. The getter is the giveaway.
     

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