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Ghost in the bass - advice please

Discussion in 'Pickups & Electronics [BG]' started by alansan, Aug 10, 2005.


  1. alansan

    alansan

    Mar 12, 2004
    Dublin, Ireland
    I have a custom built five string fretless with the following elecs:
    Aguilar OB3 and Aero jazz (middle) and humbucker (bridge). Its perfect for me and I love it.

    About 6 months ago the sound from the hb pickup started to crackle a bit. Then it would fade out completely from time to time. Slapping the strings hard at the bridge brought the signal back. The strange thing is that the output from the jazz pickup is unaffected, but I usually keep the blend pot favouring the hb.I tried the bass with multiple amps and replaced all my leads and still had the same problem. Needless to say this has never happened with any of my other basses.

    After having the bass looked at by two local techs I was told by the first guy that he could not reproduce any of the symptoms I've described and there was nothing wrong and by the second guy that the hb pickup needed replacing. In desparation I shipped it back to the original builder who frustratingly could not find anything wrong and could not reproduce any of the symptoms I've described.

    So the builder ships it back to me (at his cost) and the problem is still there, worse than ever. I'm back where I started and at the end of my patience.:mad:

    Any advice would be appreciated...
     
  2. wulf

    wulf

    Apr 11, 2002
    Oxford, UK
    I had a similar problem with my Sei bass a year or two ago, which I took back to Martin at The Gallery to have fixed. As I recall, the problem was something to do with the Schack preamp. I think he said it had two channels (one per pickup) and one of them had gone dodgy; to avoid the cost of replacing the pre-amp, he set both pickups to go through the same one, which solved the problem. Others may well be able to make a better guess than me - all I know is that it was a similar sounding intermittent problem and Martin solved it for a very reasonable price.

    Wulf
     
  3. alansan

    alansan

    Mar 12, 2004
    Dublin, Ireland
    thanks wulf, that encourages me somewhat. If it turns out to be something like that I would expect it to be done free of charge by the builder. The bass is just over a year old. Am I being unreasonable?
     
  4. aquateen

    aquateen

    Apr 14, 2005
    maryland
    have you tried a different cable? could be shorting intermittently...
     
  5. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    Here's how I'd troubleshoot this:

    First, I'd go over the control cavity, looking for bad solder joints (often look whitish or matte rather than shiny), and for places where an uninsulated wire could be near-shorting out, against another wire or against the cavity shielding. This second possibility is all the stronger if your climate (where you have a problem) is humid, and your luthier's climate or premises (where there is no apparent problem) is dry.

    If no answer there, then: Try switching the leads from the two pickups. Then, if the problem stays with the pickup, then the problem was either in the pup itself or the wire at some point between the pup and the swap point. If the problem moves to the other pup, then the problem is either the preamp itself, or some other connection after the swap point. If the problem goes away entirely, then the problem was the solder joint at which you did the swapping, and you should be able to swap back with the problem fixed.

    Perhaps a little more complicated if you have coil switching on the HB, but the same idea.

    If you have a vol-vol setup, then you have an additional swap point available, to see if the problem is before or after the volume pots.
     
  6. alansan

    alansan

    Mar 12, 2004
    Dublin, Ireland
    thanks for that pilotjones.
     
  7. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    No problem. Good luck. Let us know how it comes out.
     
  8. pilotjones

    pilotjones Supporting Member

    Nov 8, 2001
    US-NY-NYC
    Another thing I just thought of-- another reason you could have the problem, but not your luthier, is that it is possible that there is a (partial) shorting against the (grounded) cavity cover, and that they opened the cover, looked around, and then tested out the bass with the cover off- solving the problem! Or it's even possible that while there is nothing shorting against the cover itself, the cover might push two internal wires together against each other, but with it off they spring free of each other.