Realistic EL34 tube ID

Discussion in 'Amps and Cabs' started by evildik, May 1, 2016.

  1. evildik

    evildik Member

    Messages:
    1,474
    Joined:
    Aug 14, 2010
    I picked up a grab bag of old EL34 tubes from CL this weekend. A couple of them are marked "Realistic". From what I know, they just re-branded tubes from other manufacturers. These say Made in Germany. Anyone have an idea of who might have really made them?

    There are also a couple of Sylvania's. Those say GT BRITAIN on them, but I'm pretty sure I've read that means they were really made in Japan. Any thoughts on those would be appreciated too.

    I don't have a tester, so I don't know if the EL34's are good yet, but I"ve installed the three RCA 12AX7's which were included and those seem to be fine. I'm hopeful that the EL34's are as well.
     
  2. Blix

    Blix Supporting Member

    Messages:
    21,058
    Joined:
    Mar 11, 2010
    Location:
    Stabekk, Norway
    Post some good close pictures, and I'm sure you'll get some answers.
     
  3. teefus

    teefus Silver Supporting Member

    Messages:
    8,015
    Joined:
    Mar 15, 2004
    i have some realistic branded el34's that are matsushitas. great tubes. post a pic.
     
  4. Dan40

    Dan40 Supporting Member

    Messages:
    773
    Joined:
    Jul 7, 2013
    Location:
    Richmond, Va
    Made in Germany is a good bet that the EL34's are RFT's. Do they have 2 rectangular holes on the face of the plate with large staple holes punched into each side of the plate? RFT will also have a dimple in the top of the glass.
     
    Timbre Wolf likes this.
  5. dsmc80

    dsmc80 Member

    Messages:
    3,435
    Joined:
    Oct 25, 2009
    Location:
    Ohio/LA/NYC
    You can't reliably use that information to ID the tubes. We need to see pictures of the construction; getters, plates, etc.
     
  6. evildik

    evildik Member

    Messages:
    1,474
    Joined:
    Aug 14, 2010
  7. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

    Messages:
    8,995
    Joined:
    Oct 14, 2005
    Location:
    Berkeley, CA
    The Realistics are RFT, as Dan40 deduced.

    - T
     
    Dan40 likes this.
  8. mc5nrg

    mc5nrg Supporting Member

    Messages:
    8,539
    Joined:
    Mar 15, 2004
    Location:
    DC, Philly, Asquared, Upper Michigan
    Don't forget the lifetime warranty on the preamp tubes.
     
    QRSS and Dan40 like this.
  9. Dan40

    Dan40 Supporting Member

    Messages:
    773
    Joined:
    Jul 7, 2013
    Location:
    Richmond, Va
    We need some front shots of the plate structure, getter assembly and base to tell for sure. Do your "GT Britain" tubes have an etched codes near the base that begin with a "b"? How about a small hole in the bottom of the plastic guide pin? This would indicate Blackburn (Mullard) construction or possibly another Phillips subsidiary if the code does not start with the "b".
     
  10. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

    Messages:
    8,995
    Joined:
    Oct 14, 2005
    Location:
    Berkeley, CA
    Actually, your earlier post nailed it. We can see the horizontal rectangle holes in the plates, and the telltale plate staple holes. Those Realistic EL34 were made by RFT, no doubt about it.

    - Thom
     
    Dan40 likes this.
  11. Dan40

    Dan40 Supporting Member

    Messages:
    773
    Joined:
    Jul 7, 2013
    Location:
    Richmond, Va
    I was curious about the bottom two pictures with "GT Britain" stamped on them. The mica and plate structure appear to be Mullard but it is hard to make out without better pics. Hopefully he will be able to spot a "b" code on them. Might have some nice xf2's there if they test out well.
     
  12. Jeff West

    Jeff West Member

    Messages:
    893
    Joined:
    Mar 26, 2003
    Location:
    Houston, TX
    Yes, the Sylvania is a Blackburn Xf2, from '70-'73, if the base is really black as it look, don't really need a "B" code to make that one. Sylvania-branded Xf2s are especially prevalent '70-'71, it seems. On an earlier viewing I thought I saw a '70s Matsushita 6CA7 in there too, in addition to the RFT.
     
    Last edited: May 2, 2016
  13. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

    Messages:
    8,995
    Joined:
    Oct 14, 2005
    Location:
    Berkeley, CA
    Thanks Jeff. That made my slowly-composed reply irrelevant ;-)

    I was going to question possible Matsushita origin... How is it that you've made the distinction between Matsushita and Mullard, without any codes?

    - Thom
     
  14. Jeff West

    Jeff West Member

    Messages:
    893
    Joined:
    Mar 26, 2003
    Location:
    Houston, TX
    If you can see inside the tube, no other 6CA7/EL34 looks exactly like an Xf2 in all details.

    Re: Matsushita made EL34s, the most commonly encountered versions often also branded as RCA, Westinghouse, etc. are from about 1969 thru the early/mid '70s, with black bases and single halos. They look quite Mullard-like, but the "at a glance" differentiating features of these are the two raised ridges that encircle the plates above and below the slots, not found on any British Mullard, and the "split seam" in the glass on the top. Should be aware, though, that, earlier versions of Matsushita 6CA7/EL34 totally lacked one or both of those features, depending on the vintage. They had other idiosyncrasies, though!

    I'm getting some pop-up thang interfering with the photos above, they come up then disappear . . . can't be good news!

    J
     
    Timbre Wolf likes this.
  15. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

    Messages:
    8,995
    Joined:
    Oct 14, 2005
    Location:
    Berkeley, CA
    Aha! Yes. I was looking to the micas, which usually are an easy place to discern detailed distinctions. Not so much with these, however.

    Yeah - me too. It is very annoying.

    Anyway - thanks for your additional detail. I always appreciate hearing from you!

    - Thom
     
  16. evildik

    evildik Member

    Messages:
    1,474
    Joined:
    Aug 14, 2010
    Sorry if you guys are getting pop ups. It's photobucket so I'm surprised to hear that.

    Anyway, on the Sylvanias, I'm not seeing a "b" stamped anywhere, but the glass has xf2 and then below that b2k3 printed on the glass just above the base. The base is black. There is a hole in the guide pin. The pins are numbered 1 through 8 on the bottom of the base and there is no pin in the 6 slot on either of the two I have. At first I thought a pin might be broken off, but both of them are the same so maybe that's the design? The Westinghouse tubes both have 8 pins. I'm not seeing a seam in the glass on any of them.

    Thanks again for all of the input.
     
  17. Jeff West

    Jeff West Member

    Messages:
    893
    Joined:
    Mar 26, 2003
    Location:
    Houston, TX
    The"B"we're talking about is the one in "B2K3"; it's a Philips factory code, indicating Blackburn in this case. The rest of that line is a date code, for 3rd week of Nov 1972, in this case. Unlike some date codes found on tubes, that one reflects the actual time of manufacture.

    Blackburn Xf2s had all eight pins from their start in early 1962 through 1965. By very early in 1966 they lost pin 6, and for the rest of their manufacturing run lasting until fall of 1973.
     
    Timbre Wolf likes this.
  18. evildik

    evildik Member

    Messages:
    1,474
    Joined:
    Aug 14, 2010
    Man, the knowledge base on here is astounding. I knew someone would have the answers.

    Time to track down someone with a tester. Fingers are crossed that they'll still have some life. The guy I got them from said he used to change his tubes regularly when he played out in the 70's and only kept ones that still worked. He seemed a little surprised that newer amps still use tubes.

    Since the preamp tubes seem ok, I'm hoping the power tubes are as well. I'm starting to feel a little guilty since I only paid $30 for the lot. There are a few 6L6GC's as well but since I don't have an amp which uses them, I'm giving them to a good friend.
     
    Dan40 likes this.
  19. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

    Messages:
    8,995
    Joined:
    Oct 14, 2005
    Location:
    Berkeley, CA
  20. majicmerlin4

    majicmerlin4 Silver Supporting Member

    Messages:
    217
    Joined:
    Aug 2, 2014
    Location:
    SOUTHWEST
    today on my 1987 50w Marshall I just switched out all of the JJ pre amp and power tubes over to old glass....the difference is better than I imagined it would be....very happy. When I bought it amp came with the JJ's but I really was not all that happy with the tone
    Put in v1 1958 bugle boy, v2 1963 mullard, p1 tungsram and for power tubes RFT 34's which also has a small crossed sword label ( any one know the meaning?)
    A significant impact....wow!
     

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice