Paul's Guitar grounding issue

Goodsal

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Sep 3, 2020
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I have a beautiful Paul's Guitar that is very noisy. The hum goes away if I touch any metal on the guitar, including the strings. I'm wondering if there is no grounding at all on this guitar. The wiring diagram for the Paul's Guitar says "solder pickup harness shielding to tone pot casing" but I see nothing attached to the tone pot casing. I also know that typically a ground wire is run from the volume pot to the bridge, but with the Paul's Guitar there is no conduit in the wood to even get to the bridge.

Any advice re what I can do to fix?
 
A photo will help us help you. If you are new you have to post a few times before you can add a photo so tell us a few thing like , "how's your mum" and then you can post a photo.
 
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This is the Paul's Guitar wiring diagram. Note how it says to "solder pickup harness shielding to tone pot casing" and note how in my guitar there is nothing soldered to the tone pot. Any help would be appreciated!
 
First, the fact hum goes away holding strings or a metal parts is in fact indicative it is grounded properly. All my PRS do that, by the way.

In your picture the ground is connected to your tone pot's casing already via the chunk of solder connecting the ground lug to the pot's casing.

Here's mine for reference:
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Thanks for the quick response. I’m comforted knowing this is how PRS designs them and that there is nothing “wrong” with my guitar, but the noise is way beyond an acceptable level and none of my other guitars, even the single coil guitars, have a noise floor approaching this one. Is there anything I can do to quiet it down? Shielding the cavity perhaps?
 
Thanks for the quick response. I’m comforted knowing this is how PRS designs them and that there is nothing “wrong” with my guitar, but the noise is way beyond an acceptable level and none of my other guitars, even the single coil guitars, have a noise floor approaching this one. Is there anything I can do to quiet it down? Shielding the cavity perhaps?

Have had this issue with an S2 in the past, and currently with my new 594. Shielding the control cavity on the S2 worked marvelously, debating next steps on the 594.

My understanding is, our body’s proximity to the guitar causes a buildup of RF interference, things like cell phone, WiFi, etc., which becomes audible when parts of the guitar pick it up like an antennae. When we touch the strings, we ground ourselves through the guitar, and the buzz goes away.

My playing space apparently has lots of RF noise. In a recording, even my fingers coming off the strings for a short moment is audible, or if my skin and fingers are dry, the circuit won’t connect to me fully.

I assume not everyone has this problem, which is why the guitars aren’t shielded, and PRS believes shielding steals some top end. It’s a real nuisance when it manifests, though. Thinking about using the shielding paint on mine.
 
I’m glad to hear that. I shielded a Strat once with copper tape and even though it’s a purely single coil guitar it’s one of the quietest guitars I own, quieter than many of my humbucker guitars and much quieter than the Paul’s Guitar.

I think I’ll try it. But I know that when I shielded my Strat I ran a wire from the cavity to the tremolo claw which obviously is in contact with the strings. What’s the comparable method on a Paul’s Guitar? There’s no way to get from the cavity to the bridge.
 
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I’m glad to hear that. I shielded a Strat once with copper tape and even though it’s a purely single coil guitar it’s one of the quietest guitars I own, quieter than many of my humbucker guitars and much quieter than the Paul’s Guitar.

I think I’ll try it. But I know that when I shielded my Strat I ran a wire from the cavity to the tremolo claw which obviously is in contact with the strings. What’s the comparable method on a Paul’s Guitar? There’s no way to get from the cavity to the bridge.

There should already be a wire that runs to a bridge stud, and I think I see it in your photo, coming off the volume pot, the bare wire going down and slightly to the right. Functionally, if the noise goes away when you touch the strings, you know it’s all connected electronically.
 
I see that wire that goes into a hole in the cavity. But I unscrewed the bridge studs and didn’t see a wire or even a hole that went through to where the studs screw in. Im not sure that wire is making contact with anything.
 
I see that wire that goes into a hole in the cavity. But I unscrewed the bridge studs and didn’t see a wire or even a hole that went through to where the studs screw in. Im not sure that wire is making contact with anything.

Sorry to be unclear - there should be metal bushings that the studs screw into, and I think that’s where the wire is probably connected. So you likely won’t see the wire even with the stud out.
 
Thanks. I don’t see the wire, but perhaps it’s soldered to the underside of the bushing?

if so, then am I correct that I just need to cover the entire cavity with copper tape and check for conductivity with a multimeter, but I don’t have to run a wire anywhere (assuming the wire is already connected to the bridge post bushing?)
 
Thanks. I don’t see the wire, but perhaps it’s soldered to the underside of the bushing?

if so, then am I correct that I just need to cover the entire cavity with copper tape and check for conductivity with a multimeter, but I don’t have to run a wire anywhere (assuming the wire is already connected to the bridge post bushing?)

Yes. IIRC when I did my S2, the connection of the pot casings to the foil where the pots attach to the guitar top was enough to establish connectivity to the guitar’s ground wiring. Don’t forget to get the control cavity cover shielded and connected as well.
 
Thanks. This all makes sense. I cannot understand how such high end expensive guitars with such great workmanship and attention to detail could be unshielded. Extra noise is not a desirable feature!
 
I'm with you, I don't understand either irrespective of what Paul think he is hearing:

- Do you see an overlap between the position of the pickups and the control cavity ?
- Do you see an overlap between the position of the pickups and the tremolo springs/claws/bridge ?
Guess which area is already shielded and more like to affect the pickups ?

Another 'benefit' of it not being shielded also means that simply rubbing your hand/skin on finish causes static noise as well.
A suggestion is to use a laundry drying sheet to get rid of the static. I'm sure it works, but you know what works too ? Shielding the control cavity.
What others guitars do that ? The only other ones I had that were doing this were the Gibson Custom Shop ones do (reissues and even modern ones) because they aren't shielded either...

In practice it doesn't bother me (it's gone the moment I play), but I still don't find the lack of shielding amusing on such expensive instruments. And it's not exactly fun to do the shielding properly after the fact with the pots/switch all wired up.

End of rant. :p
 
It's difficult to trace the circuit in this photograph, but you can easily solder an insulated wire between the tone and volume pot casings to extent the ground reference to the tone pot. It may or may not make any difference, and if not, you can just clip it off. Be careful not to create a ground loop.
 
I had this same issue with an SE Paul's guitar. After playing at different locations I realized it was only happening at my house and my next door neighbor's house. After doing some internet research (I know, not always reliable) I came to the conclusion It was my power feed.
 
What is that? It looks like those two terminals are connected, and should not be.

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My Brushstroke 24 ( 24 fret Pauls guitar ) was 100% silent as is my 408.
I don't think Paul would find a noisy humbucker guitar OK
Contact PTC they will get you sorted.
 
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