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Additional resistor to increase output of jazz bridge pickup?

Discussion in 'Pickups & Electronics [BG]' started by Captain_joe6, Feb 8, 2006.


  1. I've got a fretless Jazz that I built, and it's loaded with Duncan Antiquity II's. I like my action high, and setting it that way gives me enough output from the neck pickup, but I can't raise the bridge pickup high enough to equal the neck one. So whenever I solo the birdge pickup, I take a cut on volume, which doesn't work so well because I'm running direct through the PA.

    I know that upping the value of pots can increase output, so by that logic, would it work to solder a small resistor in line with the positive (white) wire of my bridge pickup to increase it's output?

    Thanks all!
     
  2. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Lower the neck pickup.
     
  3. jwymore

    jwymore

    Jul 26, 2001
    Portland, OR
    I won't bet my life on this but I don't think soldering a resitor in series with your pickup will increase output.

    Higher resistance pickups have more output because the have more wire in the coil making the coil larger and capable of generating higher output signals. The higher resistance is just a byproduct of the larger coil.
     
  4. Hookus

    Hookus

    Oct 2, 2005
    Austin, TX
    Your logic defies me, and your concept of resistance is backwards. The resistance of a pot, IIRC, is measured from the input to output terminals. Your signal will fall somewhere in between, but at full volume, the pot should pretty much be bypassed in relation to the pickup, and at no volume, will pretty much be bypassed to ground. All the pot does is vary the relationship of the output to ground and the input. Additional resostors would make matters much, much worse for you, since the signal level is so small anyway. In fact, if you used a resistor over probably 100 to 200k, I don't think you would get any volume at all out of the instrument.

    What you want to do to increase the voltage, would be to lower resistance. This is basic Ohm's Law. Learn that before tinkering with electronics, it will carry you a long way.

    As was said before, raise your pickup, or install a bridge and neck volume, like a Jazz bass.
     
  5. Hookus

    Hookus

    Oct 2, 2005
    Austin, TX

    Pots dont generate any signals, nor do they amplify. The higher resistance was no byproduct, but a design specification. Remember, these same pots are used on very complicated circuits, when the value of resistance in them really makes a difference. I bet I could switch out the pots in your favorite guitar, and you would not tell a difference.

    Having seen these things on an o-scope, I would bet the house on it. What the different value pots do is change the tonal characteristics of the signal, at least some people think so. At full volume, they should have minimal effect on the circuit, at least a properly designed circuit.
     
  6. resistance on a pickup only relates to volume because more resistance generally means more windings...so it's an easy parameter to measure, but resistance does NOT equal output...adding a resistor will not increase the windings, it will only DETRACT from your signal....resistance = load = place for your sound to disappear...

    the string vibrates at less amplitude near the bridge because it is closer to the tie-down point (the bridge) where it doesn't vibrate at all...the closer to the 12th fret (middle of string) the more the string moves (amplitude = volume)...

    if you want to balance the pickups....
    1) raise the bridge pickup (done that)
    2) lower the neck pickup (preferred)
    3) add a resistor between the NECK pickup output and ground
    (see below for how to select a resistor)

    How to find the value of the resistor for suggestion #3...(caution only works for a V/V/T setup, not V/B/T)

    1...record the value of the neck pot wide open (250k? 500k?)
    2...put that size resistor in parallel with the pot (wiper to ground)
    3...dial the neck pot until the volume of the neck pickup matches the bridge when it is wide open
    4...record THAT value from the neck pot (200k? 215k? whatever)...
    5...remove the first resistor and put a resistor of the same value as determined in step 4.

    (That's why lowering the neck pickup is preferred...it's just plain EASIER)
     
  7. jwymore

    jwymore

    Jul 26, 2001
    Portland, OR
    Hookus ... I think you thought I was talking about pots, but see my post, I was talking about pickups and was basically saying the same thing as PilbaraBass. :bassist:
     
  8. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Keep piling tha absurdities up. Why even put pickups in a bass? One could save a lot of money by just wiring resistors in there. Hey, Accuswitch: look out!!!!!!!!!!!
     
  9. The thing to do if your pickup won't go high enough is to put something under it. Just unscrew it, fold up some paper or something to a good size, put it under there, and screw the pickup down to the required height.
     
  10. RaTTeR

    RaTTeR Don't forget your towel!

    Dec 25, 2005
    Riverside, Ca
    Hey, that being said, why pay so much for exotic wood when plywood and a 2X4 could do the same thing. Oh yeah, Walmart now sells bass guitars...
     
  11. I'm liking what I'm hearing here, sounds like lowering the neck pickup is the way to go. Can't raise the bridge without some work because i'm at the end of the screws, they just aren't long enough to get the job done and I'm too lazy to go find new ones that would look right. Thanks all!
     
  12. Hookus

    Hookus

    Oct 2, 2005
    Austin, TX
    Many apologies, I did think you were talking about pots, sorry about that.

    The suggestion with measuring the resistance of the neck volume pickup would really only work well with lineal taper pots, using that on audio taper pots will get a wonky volume reaction from the pot, I would imagine, if it is used other than full or no volume.

    I second lowering the neck pickup.