Noise From my Bart Preamp

Discussion in 'Basses [BG]' started by kp_funk, Feb 9, 2005.

  1. kp_funk


    Jun 9, 2003
    Hi All,

    I installed Bart pickups, and a Bart Preamp (NTMB) in my bass. I however am getting a hum when I turn my bass all the way up, and gets worse of course when I boost the treble. My first question is whether this is normal for bart preamps or do I have a ground issue. If I do, how can I get rid of it.
    Second question. What is the easiest way to ground the preamp to the the bridge? Do I have to cut through the wood? Is there a neater way??

    Do I have to ground it to the bridge or can I ground it another way? Any electrician experts out there who can give me some advice, please let me know.
  2. Willy Franklin

    Willy Franklin Supporting Member

    Feb 5, 2005
    Pittsburgh, PA
    I guess the first question would be if you installed hum-canceling pickups (Humbuckers, dual-coil) or not... If not, then the preamp is just going to amplify the noise picked up from the pickups... There has to be a post on here somewhere about the importance of shielding and all that stuff... I'm a newbie to this...
    Grounding the preamp to the bridge?? I believe that for best results, the bridge should be grounded to your output jack and that the preamp should be grounded to the output jack as well... If there isn't a wire there already, it involves carefully drilling a hole from underneath the bridge to your electronics cavity.
    Hope this helps... -Willy
  3. kp_funk


    Jun 9, 2003
    I do have hum-cancelling pick-ups. I guess I'll have to drill that hole to ground at the bridge. I hope it works.
  4. ShamrayBass

    ShamrayBass The Bass Custom Shop

    Dec 29, 2004
    Moscow. RUSSIA
    I would say that probably your bass ALREADY HAS a string ground (unless it came stock with EMG active pups, it almost CERTAINLY does!)

    of course, its possible it got broken or otherwise disconnected along the way :)

    Borrow a "multimeter" and check for continuity between the bridge and 'output jack ground' BEFORE you start cutting wood!
  5. JOME77

    JOME77 Supporting Member

    Aug 18, 2002
    I have Bart pre's in 3 of my basses and they are extremely quite. If you don't have a bridge ground run to the ground for the electronics that would certainly be a problem. You also need to make sure that all pots, switches and jacks are grounded together. The simplest way to do that is installing a single piece of copper shielding with a self adhesive in the control cavity where all components mount. The only down side to that is if a pot or switch gets loose, you lose your common ground. The best way is to soldier a wire from pot to pot (or sw). If there's not a good place to soldier to on a switch or pot, soldier to a star washer large enough for the device (pot/sw) threaded shaft to mount through. Did you purchase a pre-wired pre or did you do the wiring yourself?
  6. kp_funk


    Jun 9, 2003

    Sorry for taking so long to reply. the pre came prewired. But I think the tech disconnected it when trying to install it.