jazz bass hum and pots question

Discussion in 'Pickups & Electronics [BG]' started by chunger, Feb 17, 2010.

  1. chunger


    Jan 10, 2006
    Albany, CA
    Chunger basses by Studio 939
    I have no clue about how electronics actually work, but I recently put together a jazz bass, shielded the control cavity, star grounded everything, and am getting a bit more hum than I like still. These are single coil pickups.

    I did not check the actual pot resistance values on my craptastic cheap meter before assembling. I was wondering if a grossly mis-matched set of pots can lead to more hum.

    It's not overly terrible, just not as good as I would like. Perhaps I'm just not used to single coils.

  2. Very clean work actually.

    The star grounding is unnecessary though. You cannot get any significant ground loops in a bass.

    The value of the pots has absolutely nothing to do with noise.
    The only issue with the pots would be if you had chosen a low resistance like 25K or 50K meant for active circuits with a lower impedance output, in which case, you would get very little or no output.

    Does the hum occur only when the pickups are soloed or played at slightly different volumes, or does it also occur when the pickups are at an equal volume?

    Single coils by nature are noisy, but they should humcancel when played at an equal volume.
  3. chunger


    Jan 10, 2006
    Albany, CA
    Chunger basses by Studio 939
    The hum is faint but present when the pickups are both at 100% or when in series mode. The same hum gets louder when the pickups are offset from each other. I did notice that the hum increases and decreases depending on my orientation. Pots are 250K audio taper.

    If there is nothing more that can be done to reduce this, then, well, there's nothing more I can do and it's the nature of the beast.
  4. Textbook case of single coil hum...
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