Bias Pot Location

Discussion in 'Amplifiers' started by godwentpunk, May 20, 2018.

  1. godwentpunk

    godwentpunk New Member

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    I have a Custom 20 and I *think* the bias pot location is on the lower portion of the amps main head. It looks like its buried at the bottom of a 1/4 input jack... is that really it? I don't want to be putting my screw driver in there if that's not the correct place. I know I need to get a matched pair and when I install them, they should read the same and using both test points should yield the same result. If not, then I don't have a matched pair. Once I adjust the pot, it should effect both tubes, right??

    thanks!

    joe...
     
  2. dmatthews

    dmatthews Dave's not here...

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    That is certainly how it works for my H combo. Got a matched pair of 6L6, popped them in, and adjusted that single pot (which is rather recessed) until both tubes were as close to spec as possible.
     
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  3. bodia

    bodia Authorities said.....best leave it.....unsolved

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    Yep, same thing with my old HXDA. You just go back and forth between the two test points and adjust the single pot until they are both as close as you can get them. They may not be identical, but you should be able to get pretty close.
     
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  4. LSchefman

    LSchefman Hears Tones

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    Joe, I’d tilt the head forward a bit just to make sure you can see the screw head in the hole. Can’t be too careful!

    Also, I’m sure PRS Customer Support can clarify the location. Wouldn’t hurt to double-check.
     
    dmatthews likes this.

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