Amp Pot Question....

Discussion in 'Amps [BG]' started by PortlandBass77, Mar 25, 2014.


  1. PortlandBass77

    PortlandBass77

    Joined:
    Jul 11, 2013
    Location:
    Portland, OR
    Hi, so I am attempting to repair an old Marshall G10 MK. II amp and the only problem I can find is that all 3 of the pots are broken. All 3 of the pots are A50K and the controls are "Gain", "Contour", and "Volume". I really don't want to take the time and money to go out looking for A50K replacement pots seeing that this amp is old a cheap anyway, so I am wondering if I could use some A250K pots I have lying around without major consequence? Also what effect on the amp would A250K pots have if I do decide to do this? And yes I am sure there is no other problem with the amp. :bassist:
  2. nashvillebill

    nashvillebill

    Joined:
    Oct 13, 2002
    Location:
    Nashville TN
    You will likely have little control over your gain and volume controls. Turn the volume or gain knob up slightly and be at full volume or gain.

    For the Contour, the value forms part of the equalization circuit. A different value would throw the EQ curve off substantially.

    Go to www.mouser.com and buy the correct pots at something like $2 or $3 each. You will have to select the correct ones by measuring their physical size and going through the catalog, they don't stock them as "Marshall replacement pots" because to them they are just...pots.
  3. InsanityAmps

    InsanityAmps Supporting Member

    Joined:
    Jul 9, 2013
    Location:
    Portland, OR
  4. Mr. Foxen

    Mr. Foxen

    Joined:
    Jul 24, 2009
    Location:
    Bristol, UK
    Disclosures:
    Amp tinkerer at Ampstack
    47k might be easier to find, new standard.
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  6. InsanityAmps

    InsanityAmps Supporting Member

    Joined:
    Jul 9, 2013
    Location:
    Portland, OR
    47k is a standard resistor value but not for potentiometers. 50k is the standard pot value. A quick check with mouser shows 511 different 50k pots stocked but only 18 47k pots stocked.
  7. beans-on-toast

    beans-on-toast Supporting Member

    Joined:
    Aug 7, 2008
    Also ensure that it is an AUDIO or log taper.
  8. PortlandBass77

    PortlandBass77

    Joined:
    Jul 11, 2013
    Location:
    Portland, OR
    Thanks for the answers. I think I will try to repair the pots and if that fails I will have to buy some.

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