problems with blend control

Discussion in 'Pickups & Electronics [BG]' started by alanwolf, Dec 2, 2005.

  1. alanwolf


    Sep 22, 2004
    I’ve looked through the forums and haven’t found this problem, so I could use any suggestions:

    I recently changed out the pickups and preamp in my Warwick Jazz FNA, and al works well, except for the blend control. This will sound like an out of phase PU, but that’s the first thing I tried and there was only a tiny difference.

    New pickups are Bartolinis, preamp is Aguilar OBP-3. The problem remains whether passive or active, and whether the MM is in series or split. I used the original blend control (which had a nice, smooth slope to it before I changed everything), but it is marked at 220K, and measures 215K, which is a bit under the 250K that the Barts would like to see. The bass was star grounded with the blend body as the ground point; I left this. I’ve also checked my wiring with continuity testers to make sure there were no shorts, etc.

    Now, onto the problem: Either pickup alone sounds great, but as soon as I begin to blend in the other, there is a BIG drop in volume, the bass falls off, and the midrange gets “phasey” sounding (all of this is why I figured out of phase and switched the jazz around).

    Any ideas?
  2. luknfur


    Jan 14, 2004

    apparently swapping the jazz leads didn't resolve the issue? Sounds like a phase issue.

    Been a long time since I've messed with a blend but seems some were wired differently for whatever reason. I'd double check the wiring on the blend itself (especially crossovers) with a bart diagram. I guessing a resistance issue wouldn't have that affect but know that for fact. If you've got another volume pot laying around you may try subbing a second volume and see what you get. If nothing else, if you get the same thing then the blend is not likely the issue. It may also have something to do with the way the switch is wired.

    Continuity checks are helpful but not definitive. I can't recall any particular contradictions in the past but seems I ran across a good piece on resistance at some point that made me aware they can show good but not be good enough.
  3. alanwolf


    Sep 22, 2004
    A new 250K blend pot did the trick. Wiring was the same—I really checked this over and over again. When I pulled the old blend pot, it tests oaky, so I can't figure it out, but in any case, it's fixed now.