wiring a bass cut with a 3 way rotary switch, can anybody help me out?

Discussion in 'Luthier's Guitar & Bass Technical Discussion' started by johnny_rocks, Mar 10, 2015.

  1. johnny_rocks

    johnny_rocks Member

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    Hi to all, and thanks for checking out my thread.

    I have a question for all you wiring and guitar electronic experts out there, hopefully one of you can help me out.

    Here's why i'm posting:

    I've got a wonderful custom made semi hollow guitar with 3 P-90 pickups and a 6 way switch. I have been trying out some wirings for a bass cut control with various caps, and finally i found a match that i really like (500 kohm pot with a 3,3 nF orange drop). It really makes the guitar even more versatile and useful for me, and makes the middle position sounds stand out quite good.

    I found myself using it mostly with all the bass rolled off (pot to 0), somewhere in the middle (pot around 5) or full open (pot to 10). I would like to wire a 3 way rotary switch (3steps 4 pins) to have these settings "pre set". i think i can do it with 250kohm and 500kohm resistors wired in parallel to the cap, is that correct?

    I couln't figure it out myself, so could anyone help me out with a diagram, a drawing of the wiring or maybe a link?

    Would be awesome.

    Thanks to all!
     
  2. walterw

    walterw Gold Supporting Member

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    the only issue is that while "0" and "10" could be done with a switch, "5" might be a moving target depending on what you plug into!

    differing impedance loads can make the same settings on guitar controls act differently, so if you replace the pot with a pre-set resistor for that middle setting, you might find it to be too much in some amps and not enough in others.

    i frankly recommend sticking with the pot.
     
  3. johnny_rocks

    johnny_rocks Member

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    thanks for your reply.

    i have tried it with both of my amps and it works just fine, "5"
    on the pot seems to be the sweet spot, kind of.

    so no problem with that :aok
     
  4. bigtone23

    bigtone23 Member

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    That is a tricky target-is the pot audio taper? Many audio pots are at or around about 10% of their value on 5. I suppose you could try a 50K resistor there.
    If it's a linear pot, it would theoretically be 250K at 5. Pots are not that accurate.
     
  5. walterw

    walterw Gold Supporting Member

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    then you just need to pop out that pot and measure its resistance at "5", substituting a resistor of that same value on the middle setting of the switch.
     

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