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normal to have drop in volume when pickup blend is center?

Discussion in 'Pickups & Electronics [BG]' started by Schwinn, May 26, 2004.

  1. Schwinn


    Dec 4, 2002
    Sarasota, FL
    Just finished the installation of an aguilar obp-3 in my bass. There is, what I consider, a significant volume drop when the pickups are centered. There was volume drop with the old pre too in this position, but now it is much more of a difference. Is this normal or do think something should be wired differently?
  2. This could be total crap but maybe you have to reverse one of the pickup polarities.
  3. Nick man

    Nick man

    Apr 7, 2002
    Tampa Bay
    I notice a slight but definetly noticeable drop in any of my basses and most Ive ever played when both pickups are selected.

    I dont consider it a problem and I actually use it to my advantage. I usually favor the bridge or neck pickup (depending on the tone I want) for certain parts of songs or whole songs where I want my bassline to be more prominent.

  4. If the pups were reversed there should be very little output at all, and it'd be all nasal because the lows would all cancel out.

    I think the volume drop is something inherent in most (passive) blend knobs. Somebody who actually knows a little more than me will probly be able to tell you why.

    Josh D
  5. luknfur


    Jan 14, 2004
    For What It's Worth:

    been a while since I've had preamps and controls on my bass, but I definitely recall variations at the detent on the blends. Some volume drop and some would muddy up. It seems there is a known reason for the volume drop but I can't remember what it is.

    But I agree, that actually can be used as a benefit.

    After I got off line I thought about your question in common sense terms as opposed to something electronic. Logically, there should be a volume drop with any decrease in the neck pup. Due to positioning, the neck pup will always be louder and fatter than if that same pup were placed at the bridge position. I don't remember but the bridge pup turned up may actually sound louder than once you hit the detent due to the higher frequencies it puts out. Once you hit the detent the neck pup kicks in and the frequencies drop and so an apparent volume drop perhaps.

    Electronically it may also be a matter along the lines of feeding two pups and comparing that to a single pup while using the same amount of power.

    Been to long to recall if I always experienced a volume drop with a blend at the detent but I do recall it definitely wasn't uncommon.

    I know this has come up before and been more properly answered.
  6. PICK


    Jan 27, 2002
    Sydney, Australia
    As far as i know it shouldnt really be a drop in volume as such. Perhaps perceived volume because with most basses with 2 pick ups if you blend them you lose mids. Losing mids would seem like a drop in volume but it isnt. Most basses i have played with 2 pickups have this "Problem".
  7. Paul A

    Paul A

    Dec 13, 1999
    Hertfordshire U.K!
    Out of phase pickups - just reverse the wiring to one of them.
  8. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Well, let's see, I'd look at this from the other end, which is to say that "there is a noticeable rise in volume as the pot moves to either extreme in rotation". So the quietest point is at the midpoint. That would be normal if you're using an "ordinary" pot as your pickup blend pot. You can change this behavior by using one of the special "pickup blend pots" that Bartolini and others make, if you use one of those it'll smooth out your blend behavior, and it'll tend to keep the volume more consistent through the entire extent of the pot's rotation. These special pots consist of two resistance half-elements that are placed on opposite sides of the midpoint. When the pot is at the midpoint, both pickups are on full. When rotated to either side, one pickups remains on full while the other decreases. This results in much smoother behavior than if both pots see half the total resistance at the midpoint, in which case there will be some significant resistance in series with both pickups at that point, and that will tend to muddy up the tone. My guess is that your pickups are probably correctly phased, and that the behavior you're noticing is entirely due to the use of an "ordinary" pot for the pickup blend function.
  9. Arthur U. Poon

    Arthur U. Poon

    Jan 30, 2004
    SLC, Utah -USA-
    Endorsing Artist: Mike Lull Custom Basses
    There's slight drop in volume when the pickup blend is in the center detent on my Quantum 4 w/EMG pickups. Same with my Alembic Europa (stock,active), and Ric 4001 with Barts (passive). But I don't notice this with my active & passive J basses :confused: .
  10. Schwinn


    Dec 4, 2002
    Sarasota, FL
    Thanks for the interesting replies fellas. But I'm stupid. The pickups were out of phase after all. I say I'm stupid because I had this problem once before (those from the carvin board may remember). This time it sounded different, probably because it was a different preamp at the time so I didn't think of it right away until your replies. Anyway! Problem cured and there is no volume drop off anymore in center position, even less than with that old preamp - its very smooth now.
  11. Schwinn


    Dec 4, 2002
    Sarasota, FL
    Oh and nonstqr,

    I think I must have one of those nicer blend pots you were talking about (aguilar)...
  12. nonsqtr

    nonsqtr The emperor has no clothes!

    Aug 29, 2003
    Burbank CA USA
    Good stuff. Glad you were able to diagnose it successfully.