Question about wiring a PJ bass...

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NotTheFish
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Re: Question about wiring a PJ bass...

Post by NotTheFish » 05 Feb 2018, 12:33

There are a number of cool things you can still do.. The 1st one I would try is changing the value of the cap on your tone pot. You may find that a lower value will roll of less of the highs and at a higher frequency for both pickups may be just what you want. You can also look at switches or push pull knobs so you can change each pickup to parallel from its current series wiring. Then if you want to go crazy install a switch to put the pickups out of phase with each other. This yields all sorts of interesting tones based on the volume of each pickup. I have a fretless PJ setup like this. So there is still a lot that can be done in the passive world but for ultimate equalisation power an active preamp is the go.

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NotTheFish
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Re: Question about wiring a PJ bass...

Post by NotTheFish » 05 Feb 2018, 13:31

Also, what value pots do you have ? If you have a 500k pot on the P you might want to try a 250k.

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aphekgreg
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Re: Question about wiring a PJ bass...

Post by aphekgreg » 06 Feb 2018, 09:05

NotTheFish wrote:
05 Feb 2018, 13:31
Also, what value pots do you have ? If you have a 500k pot on the P you might want to try a 250k.
Yes, a 250K pot of the P and 500k on the J will help somewhat, if you're wanting the P to sound darker than the J.

As has been said, the only way I'm aware you can seperate them electronically, is with an active buffer or a pair of 'mixing' resistors. The mixing resistors work and is simple, but will pad down the output and make everything darker. Jaco didn't like it and John Entwistle did, so just a matter of taste.

I wonder how it would be to use a larger value resistor from the P, which you're wanting to be darker and nothing on the J?

If you were to wire the tone only to the P; you would get some isolation when the P is turned down slightly. You'd need to make sure the pot was wired to the same lug as the pickup or it would still be a master tone. Turning down the volume would be doing the same thing as using the mixing resistors. Wouldn't make any difference with both volumes up. You'd have a master tone again.
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bassbass
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Re: Question about wiring a PJ bass...

Post by bassbass » 06 Feb 2018, 12:30

The mixing resistors work and is simple, but will pad down the output and make everything darker. Jaco didn't like it and John Entwistle did, so just a matter of taste.
Nah, don't use the old stacked knob jazz circuit. The resistors in this summed the wipers and were to isolate the volume pots. Isolated tone pots is just incidental. If you look at old twin-channel fender valve amps, summing two signals this way is normal, and it's understandable that Leo used this in the first Jazz bass because no one had yet thought to wire the volume pots "backwards", with the pickups running to the wipers.

As I mentioned, keep the pickup hot wires on the wipers, but use summing resistors between the clockwise/output lugs. This way you can get some tone pot isolation with as little as 10k instead of the 220K resistors in the old fender circuit.

It really comes down to how much tone pot isolation you need. Adding summing resistors this way doesn't make the bass quieter at first. It's kind of the same as having both volume pots at 95%. It often makes the bass slightly fuller sounding.

You can find the sweet spot pretty easily by tacking in a dual gang 100K linear pot as the summing resistance and winding it up till you get some volume loss, then back it up a bit. Remove, measure then put in the closest resistors. You'll start to lose a little treble in that both volumes maxed setting, and in a PJ IME, that's OK, but less so in a J, where that scooped bright tone is really part of the jazz bass "thing".
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FunkyJase
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Re: Question about wiring a PJ bass...

Post by FunkyJase » 06 Feb 2018, 15:12

I probably should have mentioned that I dont really know anything about wiring he he - But this is ALL good info. I'll pass it on the my wire guy :-)
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