Bias voltage Question

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by joek86, Sep 1, 2005.


  1. Sep 1, 2005 #1
    joek86

    joek86 Supporting Member

    Messages:
    2,240
    Joined:
    Mar 8, 2005
    Location:
    Rochester N.Y. Area
    What is the proper voltage range to run El34's and KT-66's?

    Thanks........
     
    joek86, Sep 1, 2005
    joek86, Sep 1, 2005
    #1
  2. Sep 2, 2005 #2
    joek86

    joek86 Supporting Member

    Messages:
    2,240
    Joined:
    Mar 8, 2005
    Location:
    Rochester N.Y. Area
    I will call Carr today and find out!
     
    joek86, Sep 2, 2005
    joek86, Sep 2, 2005
    #2
  3. Sep 3, 2005 #3
    rooster

    rooster Member

    Messages:
    2,123
    Joined:
    Mar 9, 2005
    Location:
    Arizona
    Um... if you have a meter to measure the bias voltage, can't you measure the plate voltage with it? And, if you're not too sure about poking around in your amp to measure things like that, don't you think it might be worth the $$$ to have a tech bias it for you, since the amps run over $1K? Not coming down on you, but it seems to me that it would be a safer way to protect your investment.

    rooster.
     
    rooster, Sep 3, 2005
    rooster, Sep 3, 2005
    #3
  4. Sep 3, 2005 #4
    joek86

    joek86 Supporting Member

    Messages:
    2,240
    Joined:
    Mar 8, 2005
    Location:
    Rochester N.Y. Area
    The paperwork with the amp says to bias from 40 -52. there are bias probe ports built into the amp, so it's pretty easy. I will probably have a tech look at the amp, I've got a respected one in my area.
    I tried installing a KT-66 HP but the range of the Bias pot would only bring it down to 58, so I did't use it. It was a 5 on GT's hardness scale if that is relevant.
     
    joek86, Sep 3, 2005
    joek86, Sep 3, 2005
    #4
  5. Sep 3, 2005 #5
    John Phillips

    John Phillips Member

    Messages:
    13,080
    Joined:
    Mar 17, 2002
    Location:
    Scotland
    Is that bias voltage or mV measured across a resistor? (ie an interpretation of tube current). If you're using built-in bias test points I would guess the latter.

    These are not the same thing.

    You need to understand what you're measuring to know whether what you're doing is safe for the tubes or not.
     
    John Phillips, Sep 3, 2005
    John Phillips, Sep 3, 2005
    #5
  6. Sep 3, 2005 #6
    joek86

    joek86 Supporting Member

    Messages:
    2,240
    Joined:
    Mar 8, 2005
    Location:
    Rochester N.Y. Area
    It is mV measured across a resistor.....
     
    joek86, Sep 3, 2005
    joek86, Sep 3, 2005
    #6

Share This Page