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My passive p-style came back with two volume knobs and no tone knob

Bassaga

Bassaga

Sep 4, 2015
444
1,186
Arizona
#1
Took a Sire P5 into a luthier because I couldn't find a white pearloid pickguard anywhere online. Got the bass back today with the pickguard I wanted, but I plugged it in and discovered both knobs now control the volume, and I don't have any tone control. It also kinda feels like the tone is beyond 100%, like when people talk about bypassing certain wiring steps to get even brighter tone. I might be imagining that; didn't have the bass long enough to get familiar before I sent it in for this. Whatever it is, I'm honestly enjoying the tone - I just also want to be able to turn it down.

So my questions are:
1: What the heck?
2: It's just p style electronics. I have access to, but no experience with, a soldering iron. Can I fix this myself?
 
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#4
Bassaga said:
Took a Sire P5 into a luthier because I couldn't find a white pearloid pickguard anywhere online. Got the bass back today with the pickguard I wanted, but I plugged it in and discovered both knobs now control the volume, and I don't have any tone control. It also kinda feels like the tone is beyond 100%, like when people talk about bypassing certain wiring steps to get even brighter tone. I might be imagining that; didn't have the bass long enough to get familiar before I sent it in for this. Whatever it is, I'm honestly enjoying the tone - I just also want to be able to turn it down.

So my questions are:
1: What the heck?
2: It's just p style electronics. I have access to, but no experience with, a soldering iron. Can I fix this myself?
Click to expand...
Take it back.
 
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#5
dbsfgyd1 said:
Take it back.
Click to expand...
This. ^
P Bass wiring is one of the simplest passive circuits for a guitar, if your tech broke it they should be able to fix it.
Tech should have also bench tested the bass after making any changes to it before giving it back to you.
You don’t take something apart and put it back together again without testing it.
 
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#8
So the luthier made a custom pickguard for it?
Take it back. Have the luthier fix it and have them cover your travel expenses for this extra trip that could've been avoided had they checkd the instrument before giving it back to you.

Then buy a soldering iron and learn how to solder. I just fixed a friend's output jack last weekend - he twisted it to tghten the nut from the outsde and broke off both wires - and it became a whole afternoon thing for him. Basic soldering skills are very useful!
My 2 cents
 
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#9
This is most likely a VERY easy thing to fix, probably caused by the tone pot shorting to ground somewhere it shouldn't. It might not even require soldering, at least for a temporary fix. It's possible that something has just shifted a bit during re-assembly. I don't know how many times I've done electronics work, tested everything and made sure it works, stuffed everything back into the control cavity and suddenly weird things happen. This is the reason I ALWAYS test everything AFTER re-assembly. With pickup mounted electronics it's also easy to break solder connections if they are poorly done from the factory and the wires are short, although I don't think this is what has happened here.

Anyway, the luthier should be able to fix this in no time. He will probably need more time to loosen the strings and remove the pickguard than to locate and fix the actual problem.

If you want to make the luthier happy you can unscrew all the pickguards screws (and keep them safe) before you deliver the bass back to him. This would probably mean that half the job is already done.

Two things you can check yourself:

1) Both of the tone cap's legs may be shorted to ground/chassis. Make sure the leg of the tone cap that goes to the pot's terminal/lug isn't touching the pot's chassis. This shouldn't be physically possible if the tone cap is installed correctly, but I still see this all the time. If the tone cap was factory mounted in a way that makes it possible to bend that leg into the chassis it may have been bent during re-assembly, after replacing the pickguard. This would short this terminal to ground and make the tone control work as a volume pot. Fixing it by bending the cap's leg away from the pot chassis will PROBABLY be ok, but I wouldn't consider it a good long term solution. It would be much safer to re-solder it in a position where this would be physically impossible to ever happen again.

2) Make sure that the tone pot terminal with the wiring coming from the volume pot isn't touching the cavity shielding (if any). Pots can shift if you don't hold them firmly in position when tightening them to the pickguard. I don't see this problem very often with P-basses, it's far more common to cause problems with Gibson/Epi-style control cavities. But it does happen sometimes.

There is a VERY slight chance than the luthier may have damaged the pickup too. A broken coil wire might cause something like this, but I think you should have also have noticed a weaker tone if this was the case. But of course, if what you describe as a "brighter" tone is actually a "thinner/weaker" tone... But this is an absolutely worst case scenario. An experienced luthier shouldn't do something like this (although I guess everyone can have a bad day...).
 
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#10
I'm a long time Luthier and repairman. Sometimes, even the most experienced techs overlook something. I always plug in and test play any electric instrument, even if it didn't come in for that kind of repair. I'll bet he simply shorted something without seeing it.
Replacing a passive P-bass' pickguard, should require NO soldering whatsoever. In fact, there's just three nuts/washers - a jack, and two pots to loosen and leave where they sit- and then, just place the harness into the new guard. It's a quick, easy job, if the holes in the new guard are the same shaft size. Take the bass back and have them fix it. If they're a good tech, they'll likely know what they did wrong, and fix it on the spot.
 
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#13
I taught myself to solder in a weekend on scrap wires resistors and capacitors on a piece of perfboard, watching Youtube videos. I went on to build a few BYOC brand pedals, they allworked first time. By the time I got through my third pedal, I could solder quite well. I'll admit I don't understand HOW they work, but If you can follow a color-coded wiring diagram (not a schematic) you can do any common guitar wiring, and a P is as simple as it gets.
 
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#17
micguy said:
To act like the OP descries, it's shorted.
Click to expand...
^^^this

@Bassaga Any potentiometer sends some signal to one terminal and some signal to the other terminal, depending on which has more/less resistance material between the wiper and each respective terminal. A volume pot and tone pot are the same exact thing. A volume pot's terminals send the signal to either the output or ground. The only difference is a tone pot has a capacitor between the ground terminal and the ground side of the circuit.

For a tone pot to behave like a volume pot, it means the signal is being sent from the ground terminal directly to ground, either shorting past the capacitor and skipping over it, or the capacitor itself has somehow internally shorted.

--

I recently had this exact thing happen to me on a Sire P5 5-string i changed pickups and capacitor on. I soldered the circuit, put it all together, everything worked. Took it to a rehearsal, and everything worked. Got home from rehearsal, tone pot no longer worked. Went through and re-soldered all the solder points and threw in a new capacitor. Everything worked fine and has worked fine since.

Just call up the luthier and let them know the tone pot is acting like a volume pot since the pick-guard change. If they're a reasonable human, they're well aware that moving the electrics to a new pick-guard could cause exactly this thing to happen, and can probably track down the short and fix it, or drop in a new capacitor if the cap is the issue, in minimal time for no extra charge.
 
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#20
Bassaga said:
Took it back in this morning, turns out the wiring was still fine, but the pot had turned just right to ground to the paint in the pickup cavity. So that's about the easiest fix in the world, happy ending!

Thanks, y'all. I'll learn to solder eventually, but it's nice to not need to do it today.
Click to expand...

Great news!

This is also a good opportunity to remind everyone that you should NEVER ignore something as seemingly harmless as a slightly loose pot. Whenever a pot starts to loosen from the body/pickguard, make sure to tighten it as soon as possible. If not, you may suddenly experience these same symptoms, or FAR worse if a "hot" wire/terminal at the volume pot touches the shielding: a total dropout. Not very nice if it happens on stage.
 
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