Hum/Buzz (grounding)

Discussion in 'Pickups & Electronics [BG]' started by i_got_a_mohawk, Nov 21, 2005.

  1. Right, something must be wrong here, all my basses seem to buzz/hum, and it only goes away when i touch something thats grounded, strings/bridge/dials etc, so im assuming its a grounding problem

    Thing is, it happens no matter which amp i use (either of my heads or my small combo), when i use my BDDI it goes away if you touch the casing (altho the buzz happens when the BDDI isnt part of the chain). It could be that the plugs in my room arent grounding properly, but it happens at practice aswell!
    I've tried all my cables, same deal

    Could it be that all my basses have grounding issues? Or is there always a background buzz/hum when your not touching anything :eyebrow:
  2. Seems like you have a grounding problem... I mean the wiring of your house itself. If your wall outlets have 2 instead of 3 prongs then there is no ground. You can't really do anything about it unless you stick a brass rod in the ground and connected your equipment's ground to it. I know it sounds funny but that's how house wiring ground is done...
    Also, if you have several electronic equipment in your signal chain (amp, preamp, pedals, effects etc) try to connect them all on the same power strip. You might get a bit less noisy sound...
    I am not of much help here but in the majority of cases, the house wiring is the fault.
  3. eots


    Dec 18, 2004
    Cornell , IL.
    Check the sticky for lyle caldwell grounding/shielding schematic. It worked on my basses.
  4. I think you'll find its a problem inherent in how most basses are wired.

    For more information, there's a discussion about it happening in Luthier's Corner: Mysterious Wire, or something like that.

    Josh D
  5. Im in the UK, all plugs are earthed (3 prong and have an on/off switch)

    Will look it up, but i checked the wiring in most of basses and the grounds seem to be sound, physically and i checked with a multimeter
  6. + like i said, it happens at practice too, but i wouldnt trust the wiring at that place
  7. That doesn't mean you have ground though... it is likely, although it is also possible that the outlet doesn't have the actual wiring behind...
    Anyway, as said above, the wiring of the bass might be the issue.
  8. They all have grounds, i think you legally have to have them, and its the same in all the plugs, there is a ground wire there for sure

    And yeah, i was worried about the wiring in the basses, but it happens in all 5 of them :eyebrow:
  9. eots


    Dec 18, 2004
    Cornell , IL.
    Here's the link.
    Trust me.
    I've checked the very thing you have then when I used copper foil, and followed the guide lines using star grounding, I got silenced, or rather my basses did. No more having to touch the strings or knobs or bridge to stop the hum. It's a must read and do procedure and it costs less than $10 if you do it yourself.
  10. Interesting, will have to do that, altho it will be hard with the active pre amp basses, i dont see how that will change the grounding issue tho, maybe someone could explain why thats the case?
  11. Lyle Caldwell

    Lyle Caldwell

    Sep 7, 2004
    Because grounding and shielding are separate concepts.

    The ground just means there is a path from the pickups to the amp ground so you'll get current from your pickups.

    Shielding is a means of dumping all potential noise to that ground rather than letting it pollute your signal. The Brits call it a "drain" rather than a shield, and that makes more sense (I think).

    Grounding the bridge uses your body as a partial shield. Doesn't work very well, and it doesn't work at all if you aren't touching metal, but it's very cheap for manufacturers to do, and bassists are accustomed (conditioned) to it. Expect more from your instrument.
  12. Ah right, i think i see what your meaning, kindoff anyway . . . shall have to give it a bash over the holidays !