Attenuate pickup while avoiding interactions with followings pots?

Discussion in 'Pickups & Electronics [BG]' started by vin97, Aug 3, 2020.

  1. vin97


    Mar 7, 2016
    I need to attenuate one pickup before blending it with another one in a VBT circuit.
    How can I accomplish this without producing unwanted interactions with subsequent pots in the circuit?
    Initially I wanted to put an L-pad between the pickup and the blend pot but wouldn't this cause the tone pot to act as a volume since it becomes part of the L-pad?
  2. zombywoof5050


    Dec 20, 2001
    If it's just a matter of getting a good volume balance between the two pickups you could try adjusting the heights of the pickups, lower the pickup that's too loud and/or raise the other pickup.
  3. vin97


    Mar 7, 2016
    This is not an option in my case. It has to be done through the electronics somehow.
  4. Crater


    Oct 12, 2011
    Dallas, TX area
    A series resistor provides some isolation, at the expense of output level; see a "stack knob jazz bass" schematic for an example. Otherwise, you'll need a buffer or active blend circuit to completely block pickup interactions.
    Killed_by_Death likes this.
  5. Killed_by_Death

    Killed_by_Death Snaggletooth Inactive

    The trouble with putting Resistance in the path is that it WILL affect the timbre of that pickup, because the Resistance becomes part of the low-pass filter:


    The higher the value of Resistance, the more high frequencies are cut. (the cut-off point gets lower)

    One thing that guitar manufacturers do to help cut less highs is use a Volume/Volume controls layout where the pickup leads go to the counterclockwise lug of the pot:

    PawleeP likes this.
  6. vin97


    Mar 7, 2016
    Ok, so in a regular VVT wiring the tone pot sees the pickup with a variable impedance because the volume pot is adding a series resistance to the pickup.

    But if the volume pot is not wired backwards (output at middle lug), shouldn't the parallel way to ground keep the impedance stable and therefore avoid interactions with the tone pot?
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