Les Paul Standard shielding issue

[micklawson]

Hi Guys, I have a Les Paul Standard 2002 re-issue 60's neck that has been working fine since purchased in 2002. Last week when cleaning the guitar the neck pickup's screws poped off of thier springs causing me to have to carefully remove it from the cavity (after removing the strings) then re-seating it. Following this fix the bridge pickup stopped working so my guitar tech re-soldered the braid onto the volume pot as had come loose!

Both pickups are now working great but I noticed that the 3-way switch clicked when changing pickups, so again my guitar tech cleaned the contacts that fixed that.

However, now I find that I have a shielding issue as when I don't touch anything there is a hum, if I touch the strings, pickups swittch metal or bridge and tailpiece it silences the hum.

My guitar tech advised that he soldered the braid onto one of the lugs rather than the back of the pot

Could this be causing the shielding issue as am not happy to need to add shielding which would devalue the guitar as no longer standard build.

 

[poor man's burst]

However, now I find that I have a shielding issue as when I don't touch anything there is a hum, if I touch the strings, pickups swittch metal or bridge and tailpiece it silences the hum.

This is normal. The strings are connected to the guitar ground so when you touch them, it diminishes the hum.

My guitar tech advised that he soldered the braid onto one of the lugs rather than the back of the pot

Which lug? Unless your guitar tech doesn't know what he's doing, (which doesn't seems to be the case), he probably soldered the braid to a lug that is connected to the ground, as the back of the pot is. It makes no difference.

 

[micklawson]

Hi, thanks for replying my guitar tech has confirmed he soldered the neck pickups braid back on to the neck volume pot not on the ground lug, so the issue must be elsewhere, and could be that I disturbed the cabling under the neck pickuo when needing to remove it to re-attach the two center screws back through their springs, which was a bit fiddly to do

 

[micklawson]

Also before I had to remove the neck pickup to fix the screws it did not have any shielding hum when not touching the strings or metal parts as was from the Gibson factory new!

 

[jb_abides]

Have you checked the actual grounding wire? With all that work, it may have come undone.

 

[micklawson]

My local guitar tech is looking at that now so good suggestion thanks

 

[micklawson]

Hi Guys, please see my Guitar Setup specialists response below, I would value your advice as to how to proceed please!

I’ve had the LP back on the bench for a full diagnostic. I’ve performed a complete visual inspection and tested everything with a multimeter; all readings are exactly where they should be:

• DC Resistance: Spot on for both pickups, confirming no internal shorting.
• Continuity: Solid across the board (bridge, pots, pickup covers, switch, and jack). There are no loose joints or partial contacts.
• Physical Integrity: No tears or punctures in the outer braid of either pickup.

Upon checking the full length of the pickup wires, I can confirm the bridge pickup was never soldered to a ground point from the factory, and was not soldered to the other braid further up like I had suspected. It appears it was relying entirely on "pressure contact" (the two braided leads touching in the cavity) to complete the circuit. While this clearly "worked" for a while, it’s an unreliable incidental ground that inevitably will fail, which is why your pickup cut out once the cabling had been disturbed.

Here’s the crux of the issue: I suspect this is exactly why the noise is more apparent now. With the pickup only making a partial ground through pressure contact, it greatly increases the resistance in the braided shielding (which should be near 0Ω). This increased resistance acts like a filter, masking the higher frequencies where EMI lives, and likely taming the high-end of the bridge pickup’s actual tone. Now that there is a solid solder joint, that resistance is gone and the pickup is finally operating at its full frequency range.

From here, we have three options:

1. Revert to Pressure Contact: I can desolder the bridge ground and attempt to recreate that pressure connection. However, I would strongly advise against this; it is technically a "faulty" connection and will inevitably lead to the pickup cutting out again. Every schematic I have referenced for a Gibson layout explicitly states soldering the braided shield to ground for all pickups. Reverting to how it was would mean intentionally making the guitar less reliable.
2. Shielding: This is the standard fix for EMI. While I respect your wish to keep it original, it is worth noting that copper shielding tape is 100% reversible and can be peeled off without a trace. In my experience, most players see this as an essential upgrade rather than a "mod" that devalues the instrument.
3. Leave as-is: We keep the guitar at factory spec (with the now-reliable ground) and accept this is the baseline noise floor of an unshielded guitar.

 

[GreenBurst]

I would go with #3 if it was slight hum. #2 as a second choice if the hum above was too much.

I would not pursue option #1 under any situation.

 

[micklawson]

Hi GB, thanks for getting back so quick, agree not to go with Opt 1, but the hum is quite noticeable for gigging and recording, so Opt 2 sounds best, as hopefully will get back to how it should be from new. Just wondering how it got missed by the factory, as my Tech said the briad was just being held on the pot and there was no evidence of any soldering of it, so as have been very careful in handling it in recording, practice and gigs must have been very lucky not to have disturbed the unsoldered wiring before now. Was a present from my Dad when he passed leaving me some momey and a wish for me to buy the best guitar I could!

 

[micklawson]

Is shielding normally recommended for Gibson Les Paul Standards by the way as this was a 2002 re-issue of a 1960's vintage model so my tech believes the two braides from the Neck and Bridge pickups may have been tack soldered to the cavity rather than the two volume pots

 

[Subliminal lanimilbuS]

Is the grounded lug on the volume pot also grounded to the shell. The reason we ground to the shell is because is acts like a faraday cage for the electronic components inside. Some builders even went as far as putting an extra shell over the pot to help with this on guitars more sensitive to the issue. Like on old hollowbodies or semihollows such as Gibson ES-335's back in the day. If the lug is grounded to the shell is it grounded well. Other than that would have to see some pictures.

 

[micklawson]

Hi SL, not sure so have asked, what is the normal braid wiring on Les Paul Standard 1960's necks if you or anyone knows?

 

[Offshore Angler]

If it does it on both pickups and not just the one that was not soldered - get a new tech. His explanation makes zero sense. If it stops when you touch the strings - that's bad. I would check the ground wire to the bridge,

If you stop the hum that means you're the ground. If the strings are properly grounded -with humbuckers(!)- there should be no hum.

Measure the DC resistance between the strings and the outside of the output jack. It's that simple. You don't even need to take the guitar apart. It should be zero or extremely close to it. If not remove the control cover and check the between the strings and the pots and then between all the pots. I suspect you will find a bad ground to a pot or that the ground to the bridge studs was broken or disturbed. I mean, Gibson has only been wiring Les Pauls for over 75 years, I think they have it nutted by now. Just make sure it follows the schematic, it ain't rocket surgery.

A RF hum comes from the hot side, not the ground side. IN that case, with braided wire, I'd just use shielding paint. Tape works great - until it doesn't. If it's a bedroom never-leave-the-house guitar tape will suffice, but for a road warrior axe tape can come loose from the rigors of the road and short out something at precisely the wrong moment. - ask me how I know .

Or add a tin.

Chuck

 

[micklawson]

Hi guys, closing the post as issue now resolved. Thanks everyone for your help and advice

 

[GreenBurst]

Hi guys, closing the post as issue now resolved. Thanks everyone for your help and advice

Final outcome and last words to share?

 

[micklawson]

If it does it on both pickups and not just the one that was not soldered - get a new tech. His explanation makes zero sense. If it stops when you touch the strings - that's bad. I would check the ground wire to the bridge,

If you stop the hum that means you're the ground. If the strings are properly grounded -with humbuckers(!)- there should be no hum.

Measure the DC resistance between the strings and the outside of the output jack. It's that simple. You don't even need to take the guitar apart. It should be zero or extremely close to it. If not remove the control cover and check the between the strings and the pots and then between all the pots. I suspect you will find a bad ground to a pot or that the ground to the bridge studs was broken or disturbed. I mean, Gibson has only been wiring Les Pauls for over 75 years, I think they have it nutted by now. Just make sure it follows the schematic, it ain't rocket surgery.

A RF hum comes from the hot side, not the ground side. IN that case, with braided wire, I'd just use shielding paint. Tape works great - until it doesn't. If it's a bedroom never-leave-the-house guitar tape will suffice, but for a road warrior axe tape can come loose from the rigors of the road and short out something at precisely the wrong moment. - ask me how I know .

Or add a tin.

Chuck

Actually my tech guy is a very exprerienced and qualified Guitar Luthier, setup and repair specialist for 25+ years with good experience of repairing and setting up Les Paul's. He has thoroughly checked out all wiring with a meter etc. and gave me three options, 1. to roll back to tack soldering in the cavity. 2. to keep the braids soldered to the top of the pots (no lug wiring issues) or 3. to copper shield as all later Les Paul's now do.

 

[micklawson]

I have agreed with my specialist to go for shielding. Guitar back and everything working perfectly, if not even better as he has reset both pickups to factory hights (the shop must have played around with them) and also adjusted the brige back to factory action for my Britewire 10-42's preference so am very happy with the work and was only charged a nominal amount toboot! Closing this thread guys and thansk again all for your input!

 

[Offshore Angler]

Les Pauls are not copper shielded. I'd start looking for a new tech.

 

[micklawson]

Your right, Les Pauls didn’t, but your wrong about my tech who gave me the option to go back to the Gibsons factory vintage wiring of tack soldering to the cavity rather than on the top of the volume pots, or to go with shielding which many setup snd repair specialists do on other makes of guitars!

My Les Paul Std is now completely hum free for every pickup setting nor when not touching the pickups or metal parts so have no plans to sell it but will record and gig with it without any EMI issues going forward!

And will continue to use my very cabable snd experienced tech who has a very high reputation in the UK of setting up and fixing us musicians guitars, as he has already done for some of my other guitars such as my Fender American Ultra Strat!

 

[micklawson]

Is the grounded lug on the volume pot also grounded to the shell. The reason we ground to the shell is because is acts like a faraday cage for the electronic components inside. Some builders even went as far as putting an extra shell over the pot to help with this on guitars more sensitive to the issue. Like on old hollowbodies or semihollows such as Gibson ES-335's back in the day. If the lug is grounded to the shell is it grounded well. Other than that would have to see some pictures.

Sorry S, forgot to respond to your question, my tech saw that all the grounding should have been soldered to the blob of solder in the cavity however, when I pulled the neck pickup out I must have pulled the ground cables off of the blob of solder as they were all hanging loose. My tech asked if I just wanted them put back or for future proofing (in case a similar thing happend again) asked if I prefered a more modern approach used for other makes of guitar to use copper shielding. I chose the latter and do not regret it as the guitar is back to being EMI hum free and less likely to have ground wiring come loose now. So thanks for posting your helpful response mate.