Need help with electronics / clicking noise

Discussion in 'Pickups & Electronics [BG]' started by open.eadg, Apr 23, 2016.

  1. open.eadg


    Jun 13, 2010
    Hey TBers!

    I need some help to get my DIY fretless working properly. Right now I'm having problems with the electronics, but I'm not sure about the cause of it (hey, I'm a bass player, not a tech! ). Setup is: two humbuckers, 2 DPDT switches for series/parallel/single modes for each pickup, stacked vol-vol and a master tone. Everything is passive.

    If I'm not touching any metal parts on the guitar, it's quite noisy, and if I touch eg. the strings or the bridge, it makes a clicking noise, and, the bass has no noise at all. Release it, and it's noise again!
    The controls seem to work as they should be.
    What's wrong?

    (It might be important that the original electronics (some weird kind of V/V/T/T ) had no noise.)

    I've attached the schematics of the current setup, it'd be good to know if it's OK...


    Attached Files:

  2. mech

    mech In Memoriam

    Jun 20, 2008
    Meridian, MS, USA
    You are grounding your body when you touch the the strings or anything that is grounded on the bass. Your body is an antenna and will pick up and inject noise into the electronics in the bass. This will be especially true while in a single coil mode. Grounding the pole pieces of the pickups (if they aren't already) and fully shielding the control and pickup pockets will help to some degree but probably not cure it all.
  3. Looks like you may have the ground and signal wires backward on the output Jack
  4. open.eadg


    Jun 13, 2010
    Swapping the hot and ground wires on the output jack resulted in even more noise. I guess I have to re-check those switches... If they are working properly I'll do some shielding.
    Can't believe it, right now this bass is noisier than my Squier JB was. Maybe I'll have to start all over again, oh well...
    Last edited: Apr 26, 2016
  5. reddesert


    Mar 19, 2015
    Hum when you're not touching the strings or the bridge that silences when you touch the strings/bridge is interference from ambient electrical fields. That's addressable with shielding, but if the bass didn't hum before, it's likely not just shielding that is the issue. If it's really bad, that might mean a marginal connection that is very sensitive. Or, maybe you have some shielded wire that is connected wrong, such that an ungrounded shield is making your hum worse. I would think the humbuckers would reduce some of the hum if wired correctly.

    I don't understand how your DPDT switch wiring would give a single coil position. Are these on-off-on switches? As drawn, I can see how you get series at one side of the switch throw and parallel at the other side. But if there is supposed to be a single coil position in the middle, it doesn't look like that would work; only the + of one coil and the - of the other coil are connected to the pots and output. So consider checking both whether the diagram is what you want, and whether the bass is wired per the diagram.
    DiabolusInMusic likes this.
  6. DiabolusInMusic

    DiabolusInMusic Functionless Art is Merely Tolerated Vandalism

    The clicking noise when you touch the strings is likely static electricity discharging. Shielding will address that as well as the noise that stops when you touch metal/strings/bridge. Everything I know on the subject can be found in the link in my signature. There is also a great guide stickied in the pickups sub-forum.
  7. Clark Dark

    Clark Dark

    Mar 3, 2005
    series parallel switching.png

    I'd move the bare wires to the back of the pots.:cool:
    open.eadg likes this.
  8. Clark Dark

    Clark Dark

    Mar 3, 2005
    Put this in your library:

    series parallel switching.png 2.png
    open.eadg and mech like this.
  9. open.eadg


    Jun 13, 2010
    Did some testing today. I removed the switch, took out the pickup and hooked it up to a guitar cable using alligator clips (from there it goes through a Zoom B1Xon into headphones). Tried single/series/parallel functions, and guess what: the same noise at the same level, no matter what function was used. At this point I'm getting more and more confused.
    The Ohm readings of the pickup are as expected (single: 7.5 kOhm, series: 15 kOhm, parallel: 3,5 kOhm) so I don't know what to do next. Any ideas? (There's no cavity shielding as of now. Might try it...)

    (@reddesert: It turned out I've misconfigured the switch, will fix that! )
    (@Clark Dark: thank you for the drawings, saved them for future reference :) )
    Last edited: Apr 28, 2016