Identify mystery 6V6

Discussion in 'Marshall Amps' started by jak, Jun 3, 2020.

  1. jak

    jak Active Member

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    Probably no mystery for this crowd but these have no markings, and have just a thin vertical slit in the black allowing a look inside. Can’t see it unless it’s in your hand. I’ll post some pics that I already posted in a thread related thread. They’re from a 4001/studio15 I got in ‘86.
    Any guesses or info would be appreciated.
     
  2. jak

    jak Active Member

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  3. ampmadscientist

    ampmadscientist Well-Known Member

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    This is the mercury-free design which is ROHS compliant.
    The design was spear headed by Mike Mathews, at New Sensor Electro Harmonix.
     
  4. guzzis3

    guzzis3 Well-Known Member

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    I think I have some that look like that but I'd have to check. I think a lot of my 6V6s are RCAs but again I'd have to look.

    i quite like a 6V6. I know some people really don't like them but I always have. Luckily I have enough to see me out and then some.
     
  5. jlinde1973

    jlinde1973 Well-Known Member

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    They look like late 40s early 50s bottom getter Tung Sol black glass 6v6gt. Sylvania and Rca would have a smoky or grey glass. I've got a couple pairs. Nice sounding tubes.
     
  6. jlinde1973

    jlinde1973 Well-Known Member

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    I was just curious why you are changing those tubes out? noisy? man don't think current production tubes will hold a prair against them if they're good running and quiet.
     
  7. jak

    jak Active Member

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    Ah thanks. So any design other than this has mercury? Even modern ones? Or do you mean that design was the FIRST of the rohs compliant ones, but by now all are?
    Can you clarify?
    Thanks
     
  8. jak

    jak Active Member

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    Yeah I did see some on eBay. Only old rca's look like this but are stamped rca. And the rca's are black to the base. Could be rca just different ones of course.
    Yeah these have a warm crunch whether preamp or power crunch or a mix. Haven't played anything that compares. It's the amp too I guess.
     
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  9. ampmadscientist

    ampmadscientist Well-Known Member

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    I don' think they are all ROHS. New Sensor had that first one developed because of environmental regs.
     
  10. jak

    jak Active Member

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    Thanks for the info man. I'm no expert but I have noticed over the years looking at illustrations the getter plate and getter flash on the tube is usually on top. You're saying the getter plate is on the bottom on mine?
     
  11. CoyotesGator

    CoyotesGator Well-Known Member

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    Look Russian to me.

    I’ll go grab one of mine and double check.
     
  12. jak

    jak Active Member

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    Yeah they're are quiet and the heater is a nice yellow, not sure if the lack of blue glow is an indication of them on their way out, but I don't want to replace the, per se. I've noticed a drop in power amp distortion which has progressed to preamp distortion loss. Not entirely but noticeable. I replaced the preamp tubes and it helped but there's still a drop in power crunch if I drop the gain to say 3 and dime the output level. In the past that sounded amazing. Now the crunch is lacking big time. So I just wanted to drop in a couple of new power tubes to see if that corrected the issue. Kind of process of elimination. If it didn't I'd put the old tubes back in and move on to the next provisional diagnosis!
     
  13. jak

    jak Active Member

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    Cool. Lemme know.
     
  14. jak

    jak Active Member

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    Again, I've not seen every design known, but in the many years I've seen Power, preamp, phase inverter, and stereo/audio receiver or musical amp tubes, I've never seen that design inside. Always two plates,, screen in the middle, etc. what is that weird dream catcher looking design inside there?
     
  15. jak

    jak Active Member

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    Gotcha. Thanks!
     
  16. ampmadscientist

    ampmadscientist Well-Known Member

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    I don't know about the actual internal design.
    I did order some and they worked pretty good.
     
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  17. jlinde1973

    jlinde1973 Well-Known Member

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    yes that was the early 6v6 design. they are likely Tung Sols. those tubes could be as old as the late 40s is my guess. I'm pretty sure those came stock in some of the early fender tweed deluxes. too bad they are worn out...they have a killer midrange character to them. I had a pair in my Super Sonic for years until recently when I replaced them with new production jj6v6s for more headroom.
     
  18. jak

    jak Active Member

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    Ah. K. Yeah they sound beautiful. I ordered a couple of matched JJ's just in case these are actually bad. They might not be. I'll know when I get the amp serviced. Why do I hear so many people bash JJ's? Or is it just JJ preamp tubes and not their tubes in general, and not specifically powered tubes? I got these JJs simply because my reading tells me they likely provide the heaviest and hopefully earliest breakup, since I like using power distortion over preamp distortion; but you were kind of telling me the opposite in that they allow for more headroom before break up. Well, I will find out when I get a chance to test them out.
    Thanks
     
  19. ampmadscientist

    ampmadscientist Well-Known Member

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    There is nothing wrong with JJ tubes. I used them for decades.
    They are some of the most consistent tubes available, and the price is fair.

    Most likely: it is the competition planting rumors.

    JJ tubes (telefunken) is the world broadcast standard.
     
  20. mickeydg5

    mickeydg5 Well-Known Member

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    These are suppossed to be those or are those suppossed to be these?


    [​IMG]
     

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