Need help diagnosing a problem - my bass makes a very intense rumbling noise when switched to active

Discussion in 'Hardware, Setup & Repair [BG]' started by Griffin705, Jul 5, 2021.

  1. I don’t know anything about the electronics and inner workings behind the controls of bass guitars, but I’m looking to sell mine and upgrade to something else, and I want to resolve this issue before I begin posting listings. The included video is a short demonstration of the noise in question. It’s much more intense than typical pickup hum. When this video was recorded, I had just replaced the battery with a fresh one.

    Again, I have no knowledge in this realm, but I’ve opened and checked the electronics cavity, and nothing about any of the connections or wiring appears immediately suspicious.

    All three of the EQ knobs exacerbate the noise similarly, but the low EQ knob especially seems to cause crackling and popping when it’s moved.
  2. Jeff Scott

    Jeff Scott Rickenbacker guru..........

    Apr 11, 2006
    Cross-post this in Pickups & Electronics, you'll probably get better response, there.

    Also, as you've said your intent is to sell the bass, you might want to become a Supporting Member or risk having your thread deleted. :cool:
  3. sissy kathy

    sissy kathy Back to Bass-ics Gold Supporting Member

    Apr 21, 2014
    Arbutus, MD
    Try a little experiment. Lay the bass on a solid surface and try the procedure you posted again. I suspect that the rumble will disappear It seems that your pickups are microphonic. Not enough of an issue to show up in passive mode, but enough for the preamp to hear it and make it a problem. The knobs introducing noise indicates the wipers need cleaning. Spray a very brief blast of canned air or electronics cleaner into the holes on the pots.
  4. Arie X

    Arie X

    Oct 19, 2015
    dirty pots for one, and two, is there a gain adjustment screw anywhere on the preamp module?