Weird electronics issue

Discussion in 'Pickups & Electronics [BG]' started by KevB, Jan 8, 2013.

  1. Hi,

    I have an old Iby J (my first bass) that was gathering dust, so thought I'd give her some love.

    Changed out the neck pup for a dirty great big humbucker, got some CTS pots, a Sprague orange cap and a couple of micro switches and set to work.

    What I have is the neck humbucker going through an on/on DPDT for series/parallel switching and the original bridge J going through an on/off/on DPDT for polarity(phase) switching. The output of each switch goes to it's own volume pot then both to the tone and out to the jack as normal.

    Everything works perfectly apart from when the humbucker is in parallel (I think), the J volume pot acts a master volume (regardless of the polarity/phase switch) but not when it is in the series position. So if the J volume pot is down, I can't hear the humbucker!!! I don't understand what is going on as this doesn't happen when the humbucker switch is in the other position.

    I would really appreciate any thoughts or ideas or the help of someone who understand this stuff!!

  2. This is the signal flow if it helps.

    Humbucker > series/parallel switch > volume \
    .....................................................................tone > jack.
    J pup > polarity/phase switch > volume /
  3. Wow, 67 views and not one response. Where's the love brothers? :)
  4. Seems like something is miswired... pics? schematics used?
  5. abemo


    Feb 27, 2012
    Arvada, co
    Almost sounds like the series/parallel is putting both pups in series, which would cause one volume to act as master. Hard to say without pics or schematics. Also, what type of humbucker? I'm assuming its stacked in a j pup cover? Or did you route it out for a MM or mudbucker?
  6. Meddle


    Jul 27, 2009
    The standard S/P Jazz wiring that floats around the 'net is wired to defeat one volume control and set the other as a master. Not sure what diagram you used.