Identify the 12AX7's please!

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by rockon1, May 13, 2006.


  1. rockon1

    rockon1 Member

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    Just got these in a lot of tubes. Two on the left are black plates with rectangular getters that are very close to the mica. Not sure about them . The one on the right must be some kind of long plate Herleen Holland Amperex. It has a etch code of triangle 8 G on it. Any help is appreciated! Thanks Bob

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  2. rockon1

    rockon1 Member

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    Additional note. The black plates seem very similar to some Sylvanias I have. They arent quite as shiny and there are some slight differences in the rods and getter wire. Perhaps they are Sylvanias? From the code on the other I figure its a Herleen Holland Amperex made in 58?
     
  3. Jack Briggs

    Jack Briggs Member

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    The one on the left looks alot like a Raytheon, methinks;)
     
  4. rockon1

    rockon1 Member

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    All my Raytheons have round getters and a funny looking lifted part of the mica on the top piece of mica.
     
  5. Sparky6string

    Sparky6string Member

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    Were there long plate Amperex's? I have one like that and always figured it was a Philips.
     
  6. rockon1

    rockon1 Member

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    Its my (limited!) understanding that Philips was Mullard,Amperex,Valvo.Hers an interesting link.

    http://www.tube-classics.de/TC/Tubes/Valvo/Phlipscode.htm
     
  7. Sparky6string

    Sparky6string Member

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    They were all seperate brands though. A 12ax7 from Mullard was most likely manufactured at the Blackburn Lancashire plant for instance. Amperex and those branded Philips were most likely made in the Herleen Holland plant. Really I'm just asking if there were any long plate 12ax7's branded Amperex that were made in the Herleen plant.
     
  8. rockon1

    rockon1 Member

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    Got ya. Hmmm...I think Ive seen long plate Holland Bugle Boys for sale. Oh well perhaps those in the know will come along!
     
  9. Jeff West

    Jeff West Member

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    Yes, long plate 12AX7s (and 12AU7s) were made at the Heerlen plant from at least 1953 until early 1959 (when they switched to short plates). Unlike (some) Blackburn longplates, none of the Heerlen 17mm versions had halo getters.

    That particular one would be coded "mC6", if the code is still visible above the factory/date code. Those are one of my favorites for Marshalls.

    The raised mica and halo getter on the long blackplate Raytheons also started in '59, before that they had square getters on a raised single support rod, although Raytheon also rebranded Sylvanias and a few others in the '50s. I can't really see enough in those photos for positive ID of the others, but Sylvania would be a good hypothesis.
     
  10. Jeff West

    Jeff West Member

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    Yes, "angst46" always seems to be looking for and selling longplate Heerlen 12AX7s.

    It might have been a Bugle Boy in N. American market, but these identical tubes were also sold as Hammond, Miniwatt, Silvertone, Zenith, Philips, Rogers brands among many others, in various countries. You don't actually see them very often as "Mullards", more commonly the other way around in mid-late '50s (i.e., Blackburn made longplate with Amperex/Bugle Boy logo), but I'm sure there are some of those too.

    Jeff W.
     
  11. rockon1

    rockon1 Member

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    This Amperex has a "D"? getter with a funny flat piece of metal attached to the "d" side of the getter going across with the bar.No other code except the triangle 8 G on it visible.
     
  12. Jack Briggs

    Jack Briggs Member

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    I've got 2 Raytheons and they have horseshoe getters!:AOK
     
  13. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I would go with Sylvania on the two left tubes.

    I have a "Raytheon"-labeled tube that looks identical, but it may be a Sylvania as well. The real test is in the performance, and since you've got the halo-getter black-plate Raytheons to compare, Bob, I'd see (hear!) if the mystery black-plates break up noticeably less than the halo-getter Raytheons, at the same gain settings - if so, they're likely Sylvanias.

    I like those old black-plate Sylvanias as one of the most accurate and clean sounding 12AX7s I know.

    - T
     

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