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Thread: bias for vht pitbull

  1. #1
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    Default bias for vht pitbull

    I'm trying to bias a 1992 VHT Pittbull Classic 100watt anyone help what should (mA) be set at? thanks for any help
    Last edited by 100watt; 09-05-2016 at 06:54 PM.

  2. #2
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    Default

    34ma per tube

  3. #3

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    Measure the anode to cathode voltage. Set the bias current so that the quiescent dissipated power for each tube is not higher than (rule of thumb) approximately 75% of the tube's rated power. An EL-34 is rated for 25 W. e.g. if the plate voltage is 450 V, you'd want about ((25 W * 0.75) / 450 V) = 42 mA per tube, or a total of 167 mA combined for all tubes. Likewise, if the plate voltage is 500 V, you'd want 37.5 mA per tube. I probably wouldn't go higher than 75% quiescent dissipation if you value the life of your tubes. Feel free to go lower, though.

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    Thanks very much for your help

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