12DW7 Tubes - Opinions?

Discussion in 'Amps and Cabs' started by DC1, Nov 6, 2018.

  1. DC1

    DC1 Member

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    Hey all, do you think there's much difference between the current-manufacture versions of this tube (JJ and EH are the ones I've tried) and NOS?

    it's kind of an oddball tube with very different sides. Any advantage to NOS? Have you tried NOS in these? I am using a Fryette Valvulator GP/DI.

    thanks!

    dc
     
  2. Mr Fingers

    Mr Fingers Member

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    I use 12AU7s pretty often among my preamp tubes and like what they can do for you. The hybrid tube (12DW7) seems like an oddball build that might give you a teeny bit more fine tuning at the serious expense of overall tube quality. That may be a poor tradeoff. I have not used one. I avoid EH tubes, and all the "reissues" (fakes) they also market, like the plague, having been consistently disappointed by them. JJs are, in my experience, good standard tubes, but I almost always use excellent NOS tubes because they are either better or way, way better, and as a patient buyer I never have to overspend to get good ones, though those days are ending. Good luck. I recommend going with a military or audiophile grade NOS 12AU7. (I forget the tube codes for those grades -- easy to look up.) I have found phenomenal values in this tube, though I think they've been "discovered" and now, like most NOS stuff, are overpriced.
     
  3. DC1

    DC1 Member

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    Thanks, but the manufacturer says that a 12AU7 is not an appropriate substitution in this application.

    dc
     
  4. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    If 12AU7 is not appropriate, then 12DW7 may not be either. But remember - there are two triodes in such a tube, so if you use a 12AU7, you may be using one triode in a circuit that really needs a 12AX7. It may be that the 12DW7 is helpful, but you have a 50/50 chance that the 12AU7 triode is in the wrong half of the circuit. For that possibility, JJ has provided a unique ECC823 tube that has the 12AU7 and 12AX7 sides of the tube reversed from their 12DW7 equivalent, the "ECC832."

    If I were pursuing this, I think I'd try a 12AU7 first, if at all possible. Then maybe try a JJ ECC832 - or ECC823 if the triodes needed to be swapped. If the ECC832 really seemed to dial in your gain and plate dissipation needs, then I'd pursue a vintage stock 7247 (12DW7) made by Mullard, or RCA, or Sylvania, etc. But all the while I know that I have never been comfortable with the feel of a guitar circuit where I've subbed a 12AU7 in where the design was intended for a 12AX7.

    - T
     
  5. DC1

    DC1 Member

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    Thanks Thom, The tube the circuit was designed for is a 12DW7 and I believe they are using the higher-output side for amp emulation (which works well). They are adamant about not using 12AX7's or 12AT7's, etc in that position, so I am considering getting a NOS 12DW7. Have you heard the various NOS manufacturers of these? I see GE, Mullard, Sylvania and such on eBay.

    thx

    dc
     
  6. Timbre Wolf

    Timbre Wolf GoldMember Supporter Gold Supporting Member

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    I would certainly skip on from the JJ options, then, and go for a nice "new"-testing vintage 7247/12DW7. Yes, GE, Mullard, Sylvania, RCA - short or long-plate... choose your favorite flavor. Their sonic qualities will be very similar to the same make/model/production time of their 12AX7/ECC83.

    - T
     
  7. DC1

    DC1 Member

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    thanks.
    dc
     
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  8. zombiwoof

    zombiwoof Supporting Member

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    JJ didn't design that tube with the triodes reversed, there was a vintage tube that was the same. I don't recall the designation, maybe someone else will remember what it was.
    Al
     
  9. TheGuildedAge

    TheGuildedAge Supporting Member

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    Bumping an old thread.

    Does anyone use a Fryette?

    NOS tubes or new?
     
  10. DC1

    DC1 Member

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    In my GP/DI the tubes it came with sound better than any NOS I’ve tried. Including some very nice ones.

    dc
     
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  11. Jeff West

    Jeff West Member

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    Re: more vintage ones, I like Mullards. You can tell the "copper grid rods in ECC83" era ones from early '60s because they also have a copper grid rod- on the AX7 side only! I have a '61 Magnatone that calls for 12DW7. as do many Ampegs of course. They can also be used in certain 2-channel amps to give one channel with AU7 V1 and second channel with AX7 V1, if that happens to be desirable and works out with the circuit layout, as it does with my '64 AC50.

    I've got a couple of '60s W.German Telefunken 7247s that are cool looking, but I didn't really take their sound over Mullards.
     
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  12. cochese

    cochese Member

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    With the the GPDI I tried 3 NOS 2DW7 and there was no big difference between those and the stock tube.
     
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  13. Jeff West

    Jeff West Member

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    That's good, sounds like you can't lose with whatever you use. If you're playing out, good to have readily available spares that you can count on, and for a predictable cost and availability.
     

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