Question about 5V4 in a DRRI

Discussion in 'Glowing Bottle Tube Amp Forum' started by theprofessor, Nov 30, 2016.

  1. theprofessor

    theprofessor Poster Extraordinaire

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    Update: Since I got the GE 5V4GA in the mail a couple of days ago, I decided to give it a try. I'm just too curious. So far, I am really liking it. It dropped my plate voltage down 7 volts or so from 425 (where it was when I measured with the GZ34 still in) to 418 (where it was after I installed the 5V4). I ended up keeping the bias as-is, though it dropped the plate current by about 1.5 mA. I tried it up closer to 70%, but it started to sound a little congested or "flooded." So my maximum plate dissipation on the two Ken-Rad 6V6GT's is the low 60%'s.

    I really like the very slight compression the 5V4 gives. The amp is less stiff and less aggressive; it breathes just a little bit better now. There is slightly more air around the notes. So far, I'm a big fan. It sounds to me slightly more like a Deluxe Reverb should, at least in my mind (I think I have in my mind the sound of Silverface Deluxe Reverbs that ran on 5U4's. There's a beautiful kind of sluggishness there. Of course with the 5V4 it's only a touch. But it's nice.)
     
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  2. Wally

    Wally Telefied Ad Free Member

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    Remember, that voltage change rebiases the noval tubes, too....to a 'browner' point....that warms the signal up ime.
     
  3. theprofessor

    theprofessor Poster Extraordinaire

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    Wally, I assume, given my Latin from lo those many years ago, that "noval tubes" is the same as 9-pin? And by this, then, you mean it's warming up the preamp and making it browner. Right?
     
  4. Wally

    Wally Telefied Ad Free Member

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    Yessir. Nine pin. quartal, pental, septal---7 correct? , octal, noval....let's see what is this 12-pin tube to be called???
    And...yes...when you change the plate voltage, you change the biasing a bit.
     
  5. theprofessor

    theprofessor Poster Extraordinaire

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    Thanks! Yes, septal is 7. 12 would be dodecal, I think, but it would be too weird to say that!
     
  6. Wally

    Wally Telefied Ad Free Member

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    Thanks for that. I have some amps that run dodecal tubes, and therefore I keep a stash of those dodecal tubes. Usage cements the word in the memory. Now I have it. Actually, dodecahedron---- occurred to me..probably because of some geometry and/or Buckminster Fuller's designs. I just did not 'hear' the 'dodecal' in my mind....
    Dodecal is actually easier to type out than 12-pin. You don't have to reach for the -.
     
  7. theprofessor

    theprofessor Poster Extraordinaire

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    Yes. And it makes one seem smart! Advantage!
     
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  8. blues bondsman

    blues bondsman Tele-Afflicted

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    So I started a new thread asking this same exact question.
    Professor, Did you stick with the 5V4GA in your DRRI ???
    I'm about to order one for mine
     
  9. theprofessor

    theprofessor Poster Extraordinaire

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    I haven't had that amp for a little while now, but I believe I did. It works nicely to drop a little voltage from the spec'd 5AR4, it's totally safe (both rectifiers draw 2A of current), the 5V4 is not an expensive tube, and while it lowers the voltages a bit, it does not dramatically alter the tone.
     
  10. blues bondsman

    blues bondsman Tele-Afflicted

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    Thank You sir !
    I'll try one, at 20 bucks for NOS how can you go wrong !
     
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