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Biasing peavey windsor

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  • Biasing peavey windsor

    Hi i wonder if you could help me i own a peavey windsor 100 watts tube
    amp,i want to bias myself.
    I already have 4 match el34 tubes
    ive got a multimeter shall i set this to dc?

    Questions.
    Shall i put the new tubes first before any adjusted made?
    Shall i connect the red crocodile clip to test bias pot? And clip the black into the metal chassis of the amp?
    Shall i connect the cable to the speakers?
    Shall i put the power on and standby swicth then do the bias adjustment?
    Please advice me more if i missed something.thank you.
    Waiting for reply.

    Regards,
    juan

  • #2
    The nominal plate voltage in the Windsor 100 schematic is 465. Based on this rough-as-guts approximation, and using the AX84 (rough as guts) biasing guide, you want to set the bias so that the tube current is between 32-37mA for EL34s/KT66s. If you don't feel sure about any of this, take it to a tech
    Building a better world (one tube amp at a time)

    "I have never had to invoke a formula to fight oscillation in a guitar amp."- Enzo

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    • #3
      +1 TO WHAT TUBES SAID.

      By your above wordng and questions I'm not sure you know enough to be poking around in such a dangerous environment. This adjustment is done with the amp powered up and off standby so lethal voltages are present. If you have any doubts whatever about exactly what to do you should refer service to a qualified shop or individual. I can't give advice on line for this sort of action any more that I would instruct someone on how to make cyanide gas on line.
      "Take two placebos, works twice as well." Enzo

      "Now get off my lawn with your silicooties and boom-chucka speakers and computers masquerading as amplifiers" Justin Thomas

      "If you're not interested in opinions and the experience of others, why even start a thread?
      You can't just expect consent." Helmholtz

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      • #4
        This is the common Peavey approach. You don't need to open up the amp. There is a test point on the outside. Connect your meter to the test points, and set the control for what the factory recommends - if I recall, it is about -42 volts for EL34s. This is the factory recommendation. Many guys insist on running the tube hotter than that, but it is not necessary.

        Now then...

        ANY TIME you have a tube amp powered up, have a speaker connected. A tube amp without a speaker connected is ready to destroy itself.

        By THIS method, you can set the bias without power tubes, but the only readings that will mean anything would have to be taken with tubes in place.

        The test points on the amp are not meant for clips, they are tiny little jack holes designed for a meter probe point to stick into.

        Again, inTHIS method of biasing, the bias circuit is live even in standby, but again, thet only readings that are meaningful are those taken with all tubes installed and the4 amp in full operational mode, not in standby.
        Education is what you're left with after you have forgotten what you have learned.

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