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P Bass pickup on "PJ" setup sounds too muddy?

Juani Vitale

Juani Vitale

Jan 27, 2018
16
17
39
Argentina
#1
Hi everyone. I seem to have an issue with one of my pickups and I'm not sure what's causing it: I recently finished building a PJ style Precision Bass. For the Precision pickup I'm using my old trusty Pure Vintage '58 and a Pure Vintage '74 (bridge) for the jazz pickup. Before this I had the '58 installed in two other basses (in those cases, regular P Bass setup, with no jazz pickup) and it sounded amazing in both of them, but for some reason it's sounding incredibly muddy in the new bass without the Jazz pickup engaged. Can this be some sort of wiring issue? I wired the bass with a volume pot for each pickup and a master tone following this scheme https://www.talkbass.com/attachments/download-jpg.1054968/

Is it ok to use 250k for all three pots? maybe something to do with the capacitor value? btw the cap is the same one I had on my previous P Bass with the same '58 pickup and it sounded great. Also there seems to be no "tone" problems at all with the jazz pickup...

Thanks to everyone in advance and have a great weekend!
 
#3
Passive pickups are very interactive with their controls in terms of the tone you get. Even when your volume pot(s) is turned all the way up, it's still adding resistance in parallel and altering the tone. The value of the pot determines how much it impacts the tone - lower value pots will roll off more treble, high value puts will roll off less treble and sound brighter.

Your two-volume circuit has two pots in parallel with the output, your old P bass wiring only had one. The resistance of two resistors of the same value in parallel is half the value. If you're using 250k volume pots, it's equivalent to 125k in parallel. That's pretty low and will sound pretty muddy.

If you had 250k pots in your old basses and want the same tone in the new bass, use 500k in this bass and you'll get the same exact tone. Two 500k pots in parallel is effectively the same as one 250k pot.
 
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#9
Personally I would go with 500k for all three. You can mix and match whatever you want, there are no rules! Get a couple pots and try things out. 500k volumes and 250k tone might sound best to you.
 
#11
When the bridge volume control is all the way down, the bridge pickup literally is out of the circuit - both ends are at ground. Regardless of what you set the pot at, the resistance of the volume pot is always "in circuit" though, in parallel with the pickups and output (from hot to ground). You could certainly try disconnecting the bridge pickup AND it's volume pot, if you wanted to hear the difference.
 
#12
Reading all your comments about circuit and pots I realized I was a bit too worried about just "copying" a circuit instead of thinking of my end-goal first, so here it is, maybe you can help me achieve it:

I use the P pickup alone like 75% of the time and I do play around with the volume and tone for that pickup. The J pickup I use it to add some bite ocassionally but I don't really mess around with either its volume or tone. In this case I thought of the volume pot for the J pickup to use it basically as a switch, since I don't like the idea of an actual switch and drilling another hole in the pickguard. So maybe there's a way to "bypass" the tone only for the J pickup? would that make the P pickup behave like in a regular Precision when the J volume is all the way off?
 
#13
A switch would get the literal "behave exactly like a P bass" with the J turned off. You could use a stacked 250k pot for master volume and tone, and then use the newly freed hole for a switch that cuts the J. Then you'd get a 100% exact copy of what you're used to with the J switched off. The downside, of course, is that the J is either on or off, there's no volume control possible to change the ratio between P and J.

Another option would be to use stacked 250k pots for master volume and tone, and use a push/pull pot in the other hole as a J volume, and pulling the pot out cuts the J and it's volume out of the circuit. Once again you'd get "normal P bass" behavior and tone with the J cut out, and you'd be able to control it's volume when it was added in. But of course adding it in adds it's pot to the circuit so you'd be back to square one when blending them.

Or just put 500k pots in and see how you feel about it. With 500k pots and the J turned all the way down, you'll get the same tone as you're used to on a bass with only a P and 250k pots. The only difference will be the slightly different feel to a 500k volume pot on the P, since a higher value pot will feel different as a volume control. But I'd be willing to bet that you won't notice or care about that difference, and you'll get the exact tonal result you want.
 
#14
Rolling Thunder said:
Asking for a friend, can you mix 250k volumes and 500k tone pot (assuming a VVT set-up)?
Click to expand...
Yeah.

Normally, on guitar, you would run your buckers (or splits) on 500ks, and your singles on 250ks. It's a very very common thing.

With one master volume and a switch, you would wire a 250k resistor to the switch node with your single coil pickup on it, to drop just the single down to 250k.
 

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