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How many different ways to wire a P-Bass?

Discussion in 'Pickups & Electronics [BG]' started by NickInMesa, Apr 17, 2009.


  1. I fixed a P-Bass the other day which had been badly mistreated (it's a Johnson I bought for $30 -see my other thread about the Dragonfire pups).

    It was wired in an odd manner, with the capacitor soldered from the pole of one pot to the neutral of the other...

    When wired this way, the two pots controlled the volume and the sound was weak. My guess is that the previous owner screwed around with it (as he did with other parts of the bass).

    I used Martin Koch's book and rewired according to his schematic, now the pickups works perfectly, one pot as volume (and it seems to be a log pot, which I was not sure), the other as tone (and it seems to be a straight pot, which I was not sure either, apparently I was lucky).

    But when I look online, I find that there is indeed a way to wire the P Bass with the capacitor between the two pots.

    That does not seem right, because when I drew the schematic it did not look like it would work properly... And indeed it did not.

    So how there is more than one published way to wire a P?

    Thanks!
     
  2. Liko

    Liko

    Mar 30, 2007
    Well, basically the tone pot should take the pickups' output and send it through a capacitor and a potentiometer, which will filter out the high frequencies. Ideally, it makes no difference which one comes first. So, your average P-bass will have the pickup's hot lead coming into a side terminal of the volume pot, with a parallel lead between that same terminal and the wiper terminal of the tone pot. The capacitor will then either be wired in series with a lead to the ground jack or will simply be soldered to the tone pot shell (which should be grounded one way or another). You should be able to swap the wire between the volume and tone pots with the capacitor.

    Things to watch out for that may have caused the problems you describe:

    * regardless of where the capacitor is, it should never be in parallel with a wire in the circuit. If this is the case, the low frequencies will have a path to ground of the same resistance as the high frequencies, turning the tone pot into a volume pot.
    * the volume and tone should not be wired in series. Though this actually is possible, the multiple potentiometers will lose tone from the pickups.
     
  3. walterw

    walterw Supportive Fender Gold Supporting Member Commercial User

    Feb 20, 2009
    alpha-music.com
    there are different ways to add the tone pot to the circuit, and they all work pretty much the same. the tone pot is in series with the cap, and one side of that chain goes to hot while the other goes to ground. (technically, the pot is just a rheostat, because you're just using two lugs of it to form a variable resistor.)

    when turned up, the tone pot's resistance blocks the cap from doing anything, and as it's turned down, it lets the cap drain more and more of the highs from hot to ground.
     
  4. slyjoe

    slyjoe Supporting Member

    Jun 28, 2008
    Valley of the Sun (AZ)
    If by "neutral" you mean the ground lug of the other pot, that is ok. All grounds are the same. Electrically, there is no difference as to which ground the cap connects to.
     
  5. there are only two ways actually... series and parallel!!! out of phase P pu doesn't sound that good...
     

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