DC current on tone pots.... effect?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by JubileeMan 2555, Jan 30, 2012.

  1. JubileeMan 2555

    JubileeMan 2555 Member

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    Just curious. I don't know if any tone was improved, but I noticed my mid pot on my marshall scratchy when I'd turn it when playing.

    SO I replaced the .022uf Sozo Mid tone cap and the scratch is gone.

    Just wondering what DC current over a leaky cap into tone pots might do to the guitar signal/tone..etc?
     
  2. Billm

    Billm Member

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    DC on pots = scratch.

    But you already figured that out!

    It's likely that there would be no other effect on tone.
     
  3. pdf64

    pdf64 Member

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    As long as it doesn't get to the following grid, which in this case it wouldn't as there's another coupling cap in series.
    If it did, the bias / operating point may get shifted.
    Pete.
     
  4. Ronsonic

    Ronsonic Member

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    Couple of things. It makes the pots with the DC on 'em noisy. If enough gets through to the grid of the next tube stage it messes up the bias and then you get all kinds of bad stuff like muddy sound, fuzzy blobby distortion or even melt down the tube. Believe it or not a 12AX7 can redplate.
     

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