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5Y3 vs GZ34 - B+ Voltage

Discussion in 'Amp Tech Center' started by Jeru, Apr 28, 2020.

  1. Jeru

    Jeru Tele-Holic

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    I'm going to turn this Knight amplifier into something like an
    ab763 without Verb or Trem. This is maybe my 4th-5th build.

    The PT is center-tapped. With 120vac in and using a 5Y3, I get
    375vdc measuring between rectifier pin 8 and the center tap.
    Substituting in a GZ34, I should get a higher DC voltage reading
    because a GZ34 drops less voltage, right..? Well, it's exactly the
    same, and I dunno why.

    Any thoughts or gentle explanations of why I'm an idiot would be
    appreciated.

    Knight 1.JPG Knight.JPG IMG_5779.JPG
     
  2. DADGAD

    DADGAD Friend of Leo's

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    With a load on the power supply, there will be more voltage drop using the 5Y3.
     
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  3. jondanger

    jondanger Poster Extraordinaire Silver Supporter

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    I seem to remember having a similar experience once when testing a GZ34 vs a 5U4, and when I put the preamp and power tubes in, that's when there was a difference in the voltage drop.
     
  4. Jeru

    Jeru Tele-Holic

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    Alright. Subtext: Just build it.
    Thanks.
    JR
     
  5. elpico

    elpico Tele-Afflicted

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    V = I x R. no I, no V.
     
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  6. DADGAD

    DADGAD Friend of Leo's

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    Ohm my goodness!
     
  7. Jeru

    Jeru Tele-Holic

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    YES / Totally / DUH / thanks.
    JR
     
  8. Junior Little

    Junior Little Tele-Meister

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    Or you could put a load on it with a big ol' resistor. Pretty sure I saw that done somewhere...
     
  9. Lowerleftcoast

    Lowerleftcoast Friend of Leo's

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    I don't care who you are, that's funny right there!

    :lol::lol::lol:


    Larry the cable guy.
     
  10. DADGAD

    DADGAD Friend of Leo's

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    I couldn't resist as I'm currently in a humorous mood.
     
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  11. archetype

    archetype Fiend of Leo's

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    Thanks for incorporating the word "resist" in the answer.
     
  12. DADGAD

    DADGAD Friend of Leo's

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    Do I get half a credit for the word currently?

    Maybe I don’t know watt I’m talking about.
     
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  13. The Ballzz

    The Ballzz Tele-Afflicted

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    That all boils down to two thirds of a pun, P U. :p
    Just Amplifyin'
    Gene
     
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