Whats the formula for setting Bias?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by Red Planet, Jul 30, 2006.

  1. Red Planet

    Red Planet Member

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    I've got a freakin chart and everytime I need something that aint on the chart I forget.

    I just need the dissapation calculation math.

    Thanx
     
  2. Blue Strat

    Blue Strat Member

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    Excellent color coding!
     
  3. Red Planet

    Red Planet Member

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    Thanx OTM but let me make sure I've got this right.

    percentage times dissapation divided by plate volts equals cathode current?

    Youve got all this technicaly looking right I'm sure but I'm gonna need the Red Neck version.:rotflmao
     
  4. danieldroukas

    danieldroukas Member

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  5. Guinness Lad

    Guinness Lad Silver Supporting Member

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    Here's a very useful site, great when you forget everything.

    http://www.kimber.com/atomic-struct/BC5-10.htm

    E (voltage)= I (current) * R (resistance)

    and all the other variations which can be figured out by manipulating the equation.
     
  6. mbratch

    mbratch Member

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    Keith, looks like you're calculating exactly per the formula Tele gave, so that lines up. :)

    Also, after adjusting the current, you want to double check the plate voltage because it can vary after the bias resistance has been changed.

    And finally, you may not want to peg it at 70%, but you may want to choose a lower number if it sounds better to your ears. 70% is the maximum suggested per the tube specs.
     

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