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volume drop with V/V/preamp jazz

Discussion in 'Pickups & Electronics [BG]' started by basey, Aug 13, 2007.

  1. basey


    Jul 31, 2005
    San Antonio, Texas
    Hello, I put in some bartolini passive pickups in my jazz bass last week and they sound great. They go into a EMG BTC two-band knob. The problem I'm having is when I turn one of the volume knob down from 10 the tone changes alot and then tapers down after that. It doesn't matter which one, they both do it. I don't know if this is normal and I just didn't notice it with the other pickups or something is wired wrong.
    If it is normal, is there a workaround?

    I searched for awhile and couldn't find anything. Maybe I don't know what words to search for.

    Thanks for any help.

  2. paullong444


    Jul 16, 2007
    Sun Valley, California
    Paul Long
    It sounds like the pots aren't what they call "audio tapered". Tapered pots change gradually, non-tapered pots drop quickly then cut off. I don't think this is the problem though, I can't see EMG making a mistake like that. I thought their stuff is pretty easy to install and pre-assembled. So I am not sure what the problem is. You didn't change the pot or do something wacky like that did you?
  3. basey


    Jul 31, 2005
    San Antonio, Texas
    nope, I just changed the pickup wires to the new ones

    The thing is that when both pots are fully turned there is a volume boost, but as soon as you turn either knob the slightest bit down, it goes away. (Maybe that discibes it a little better)
  4. Those are standard audio taper pots, probably 30% taper which means that as you roll the volume down ½ of the total resistance is in the first 30%. So there is a drop.

    Ever noticed how on some amps the volume goes up until about 2:00 o’clock and then the amp just gets thicker sounding but not louder?

    Reverse the wiring, on the two outside taps and you will get a really nice roll off, but the pot will work backwards. Or change them out to linier taper pots.

    Btw pot markings will show something like 250K A for audio taper and 250K B for linier.

  5. CyberSnyder

    CyberSnyder Gold Supporting Member

    Jun 19, 2003
    I Endorse Alien Audio Basses
    Is the EMG BTC designed for active pickups rather than passive?
  6. m.oreilly


    Jul 5, 2006
    Ukiah, CA
    that's what i thought...and why i removed my btc...
  7. basey


    Jul 31, 2005
    San Antonio, Texas
    Your right, EMG makes two versions of the btc eq. One for actives and one for passives. I have the right one for passives, and like I said, I replaced pickups that were working fine with the volumes.

    I'm not sure if I have my answer or not. It's not that the volume drops really fast as I turn it. It's that the volume drops instantly if it is not in full contact with both maximum settings.
    Maybe I should record it when I get home tonight. To give you a better idea of what I'm talking about. I seem to be having a little trouble describing the symptoms.
  8. basey


    Jul 31, 2005
    San Antonio, Texas
    I managed to get a recording of the problem on the computer, but it doesn't sound as pronounced as it does through my amp.

    Here's the link volume troubles
    In the clip, after I play the notes I moved the each knob away from full a couple times. If you listen close you can here a sort of clicking sound. It doesn't sound as bad on the computer as it does through the amp though.
    Thanks for all your replies so far though. I'll try changing the pots to linear if no one can think of anything else.


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