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Why cant a PJ sound like a real P
- Thread starter pattyløve
- Start date
Silly me, doing half a job as usual.
Pic edited accordingly. Okay now? Tone pot was right anyway, I think.
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Alright Jimmy, I'll give you the challenge then.
Go down to RadioShack and pick up a couple of 250K (or 500K if that's what's in your P bass) resistors. It should only cost a buck or two.
Solder one of them across terminals one and three of the volume pot on your P-bass. (The P, not the PJ)
If you can't solder, then just wrap the lead around real tight and make sure it's making good contact for the test.
Now play your bass and tell me if it sounds different to you.
Do you notice any less output?
I was curious about this once, and actually performed this experiment. I wired in a 250k resistor between the output and ground, and hooked that up to mini toggle switch, so I could quickly switch the resistor in and out of the circuit.
The affect of the extra resistive loading WAS audible, but just hardly. The volume was slightly decreased, and the treble was VERY slightly attenuated. If I hadn't been able to flick that switch back and forth I never would have been able to tell the difference.
My verdict? I spent way too much time on this pointless experiment.
I was curious about this one, and actually performed this experiment. I wired in a 250k resistor between the output and ground, and hooked that up to mini toggle switch, so I could quickly switch the resistor in and out of the circuit.
The affect of the extra resistive loading WAS audible, but just hardly. The volume was slightly decreased, and the treble was VERY slightly attenuated. If I hadn't been able to flick that switch back and forth I never would have been able to tell the difference.
My verdict? I spent way too much time on this pointless experiment.
Were the volume and tone controls on full?
Were you using an amp, or did you go direct?
I play my bass direct through studio monitors, and I hear a big difference.
i doubt anyones really going to do it, but i agree that it will change the tone. i also agree with magnetic string pull being added.
but, i dont agree that my p/j does not sound like a regular p bass. it does. without a doubt, you cant argue that. but, the sound quality of the p-pickup soloed, might not be exactly the same as a similar bass without the 2nd pickup.
Okay, just been doing some sums.
Suppose the P pickup induces a current of 1 amp (I know that's silly, but it's just a figure for modelling the effect - I could have picked 100A or 1mA and the following ratios would still hold true).
Right, think of a traditional P pickup setup here. I just checked the resistance of a pickup and it's in the order 8-12K. If the volume for the P pickup was maxed, and the connections are pretty much zero ohms, then all of the 1A would get to the output. Correct?
Now, let's conect the J into the circuit. It's true that some of the signal from the P will find its way to ground through letters D to C (in my diagram) in that case and this will reduce output. But if the resistance of the pot is 250K (J pickup on zero), the current going through that branch will be split in a way that depends on the resistance of the two branches of the circuit. I think about 10/250 of the current will find it's way through that branch, if I understand correctly (or thereabouts). That means instead of 1A flowing to the output, 960mA will make it. Is that correct?
If it is, I'd be quite surprised if the difference was really audible.
Suppose the P pickup induces a current of 1 amp (I know that's silly, but it's just a figure for modelling the effect - I could have picked 100A or 1mA and the following ratios would still hold true).
Right, think of a traditional P pickup setup here. I just checked the resistance of a pickup and it's in the order 8-12K. If the volume for the P pickup was maxed, and the connections are pretty much zero ohms, then all of the 1A would get to the output. Correct?
Now, let's conect the J into the circuit. It's true that some of the signal from the P will find its way to ground through letters D to C (in my diagram) in that case and this will reduce output. But if the resistance of the pot is 250K (J pickup on zero), the current going through that branch will be split in a way that depends on the resistance of the two branches of the circuit. I think about 10/250 of the current will find it's way through that branch, if I understand correctly (or thereabouts). That means instead of 1A flowing to the output, 960mA will make it. Is that correct?
If it is, I'd be quite surprised if the difference was really audible.
Ya, sounds like work to me 
I'm OK with the sound of my PJ's as they are. So I lose a little high end or a tiny bit of volume...I'm not a volume or high end freak, and I use 3 or 4 pedals that would probably do as much damage as wiring in a second pot. It's interesting to know, so thanks for that, but for me it has no practical application.
I'm OK with the sound of my PJ's as they are. So I lose a little high end or a tiny bit of volume...I'm not a volume or high end freak, and I use 3 or 4 pedals that would probably do as much damage as wiring in a second pot. It's interesting to know, so thanks for that, but for me it has no practical application.
I moved the volume and tone controls all over the place, and it behaved just as the laws of physics demand. A small decrease in volume and treble.
So you've actually listened to the same instrument both with and without extra resistive loading?
I haven't tried the resistor thing, but I have tried the difference between 250K and 500K, and you can hear it.
We are dealing with a drop in voltage more than a drop in current.
Also, with the P maxed, it doesn't go straight through per se, there is a 250K ohm resistance to ground.
Well, Ive learned a bit about wiring pickups from this thread - so thanks.
I've also learned that a PJ with the J turned down is pretty much a P.
I've also learned that a PJ with the J turned down is pretty much a P.
Current is proportional to voltage, though. Yes?
Understood about the 250K. Pretty high compared to the internal resistance of the pickup. And what you say would, of course, apply even if you took the J pickup out of the circuit completely.
I was talking about the amount of signal from the P that would get to the output if it was on its own, and how that changes when you introduce a J pickup turned down to zero. The answer seems to be - hardly at all.
There's a bass players' joke in here somewhere...
"What do you call a PJ with the J turned down?"
"A P."
Well guys, I really don't feel like arguing about this anymore.
If you add a second volume pot to a P, it's still mostly going to sound like a P.
The question is exactly how accurate you want that to be when comparing to a regular P bass.
If you're like me, you will take it to levels of utter ridiculousness to get it to match the exact tone and vibe of a regular P bass, but I guess most of you guys don't care enough for it to matter.
I am working on a PJ bass right now with a VVT arrangement plus a 3 way switch.
That seems to be the most flexible option for me at least, because even if you don't think the extra pot makes a difference, at least you can switch between the pickups a lot quicker than fiddling with the volume controls.
If the 3 way switch isn't your cup of tea, you can put a simple bypass switch for the Jazz volume on a push/pull pot.
If nothing else, you could switch between P and P+J quicker than dialing in the volume knob where you liked it on the J.
If you add a second volume pot to a P, it's still mostly going to sound like a P.
The question is exactly how accurate you want that to be when comparing to a regular P bass.
If you're like me, you will take it to levels of utter ridiculousness to get it to match the exact tone and vibe of a regular P bass, but I guess most of you guys don't care enough for it to matter.
I am working on a PJ bass right now with a VVT arrangement plus a 3 way switch.
That seems to be the most flexible option for me at least, because even if you don't think the extra pot makes a difference, at least you can switch between the pickups a lot quicker than fiddling with the volume controls.
If the 3 way switch isn't your cup of tea, you can put a simple bypass switch for the Jazz volume on a push/pull pot.
If nothing else, you could switch between P and P+J quicker than dialing in the volume knob where you liked it on the J.
I'd be happy to have a PJ with a 3-way switch. My converted Fender used to have EMG's on a 3-way. I think it's very practical, and would be cool on a new build. I'm just saying I'm not going to mod my current basses for it because the difference isn't enough for me to care one way or the other.
