Guitar Grounding Common Misconceptions?

[southpaw219]

Hi, Jonesy. Thanks for sharing your wealth of knowledge on these boards. I'm doing my best to learn how to do my own guitar work, but I'm finding certain hurdles along the way.

I'm very wary of soldering to the back of pots. I know it's been done for a dog's age and all that, but I just don't like the idea of them absorbing all that heat. Even from just touching the casing for a few seconds with my 40W iron, they cook.

So, I've been looking into alternative grounding methods and came across the "star" idea. I felt pretty excited about trying it out, but after reading your posts about the different kinds of ground circuits and how the bus wire is essential to link all the pots together, I'm a little crestfallen.

Please look at the diagram below, which I made to depict how I'd ideally rewire my Swede (in its stock configuration). Could you explain to me if I'm way off course and, if so, how I can correct it?

Thanks.

[jonesy]

Learning to solder is an essential part of modding and upgrading guitar wiring. The more you solder, the better you should get at it until you feel more comfortable soldering to the back of the pots. "Practice makes perfect" they say.

The star grounding is a modern approach to wiring and you can see it used in many of the diagrams for Bourns pots etc. but is not a wiring method that I ever use. Most, if not all of my LP rigs get wired up with the vintage 50's style wiring. With the star grounding you end up with a lot more wire inside the cavity and it can turn into a cluster, just look at your wiring diagram. Grounding to the back of the pots has worked for over 60 years, very simple effective method for guitar grounding.

I looked at the diagram you supplied and it looks like the caps are soldered to the tone pot and then right to ground (modern wiring) vs going from the tone pot to the center lug on volume pot (50's wiring) so you will most likely get some muddiness when the volumes are rolled down. 50's wiring preserves your highs and is user friendly with tube amps.

It's good to try new things, but don't shy away from soldering to the back of the pots and 50's style wiring in lieu of a different wiring method just because it is easier. Learn the basics, practice soldering on some old pots until you get the hang of it and you will have the skills you need to get the job done correctly. YMMV

[southpaw219]

Hi, Jonesy. Thanks for the reply. You're right that I depicted the stock scheme. Here's the same "star" grounding idea, but with the '50s scheme.

Additionally, do you have any feedback on the "tone filter" switch I've depicted? I understand what it does -- changes the capacitance value applied to the tone -- but I'm not exactly clear on how it does it and what, exactly, it does, scientifically (as opposed to aurally). Those two caps on the tone filter switch are 4700 pf and 0.015 uf.

And, finally, when I disassembled my guitar, I found that the pot shafts were significantly corroded. The holes in the body through which they go are caked in white dust akin to (and, I infer, directly from) the corrosion on the pot shafts. The hole for the input jack is similarly caked in white dust. Is this a sign of a significant problem?

[southpaw219]

Don't know how much of a foul it is to follow my own post without a reply, but I mocked up a scheme wherein I use wire with a braided shield. I'm still avoiding soldering to the backs of the pots, but I'd appreciate any feedback.

I revised it a little to ground the lugs of the tone and volume pots to both the incoming braided wire from the pickup and the outgoing braided wire to the switch ... I've heard countless debates about grounding loops, and I don't know if I've depicted any ... but the diagram is there to be critiqued.

Thanks.

[jonesy]

Originally Posted by southpaw219

Hi, Jonesy. Thanks for the reply. You're right that I depicted the stock scheme. Here's the same "star" grounding idea, but with the '50s scheme.

No problem bro. That looks a little better, but I still prefer the vintage 50's style wiring myself.


Additionally, do you have any feedback on the "tone filter" switch I've depicted? I understand what it does -- changes the capacitance value applied to the tone -- but I'm not exactly clear on how it does it and what, exactly, it does, scientifically (as opposed to aurally). Those two caps on the tone filter switch are 4700 pf and 0.015 uf.

I don't know all the details on how it is wired up but it looks like it is just using those caps as some type of a low pass/high pass filter. Very similar to part of the Varitone wiring or the way coupling caps (in/out) work in a Fuzz pedal.


And, finally, when I disassembled my guitar, I found that the pot shafts were significantly corroded. The holes in the body through which they go are caked in white dust akin to (and, I infer, directly from) the corrosion on the pot shafts. The hole for the input jack is similarly caked in white dust. Is this a sign of a significant problem?

Oxidation can be caused by environmental conditions and also by the materials involved. I would just make sure that everything get's wiped down good and none of that residue is left when you install the new pots.

[southpaw219]

Originally Posted by jonesy

Oxidation can be caused by environmental conditions and also by the materials involved. I would just make sure that everything get's wiped down good and none of that residue is left when you install the new pots.

I was actually considering keeping the original pots, since they're CTS and they have resistance pretty close to their rated 500 kOhm values:

Neck volume: 463 kOhm
Neck tone: 498 KOhm
Bridge volume: 478 kOhm
Bridge tone: 473 kOhm

I was just worried that the oxidation on the shafts might have compromised them, in some way.

The capacitors are junk, though. I'm looking forward to when my Russian PIO replacements arrive.

[jonesy]

Originally Posted by southpaw219

I was actually considering keeping the original pots, since they're CTS and they have resistance pretty close to their rated 500 kOhm values:

Neck volume: 463 kOhm
Neck tone: 498 KOhm
Bridge volume: 478 kOhm
Bridge tone: 473 kOhm

I was just worried that the oxidation on the shafts might have compromised them, in some way.

The capacitors are junk, though. I'm looking forward to when my Russian PIO replacements arrive.

I you decide to keep those CTS pots they make different types of electrical contact cleaner that you can spray down into those pots and that should remove the oxidation. Spray it down into the shafts and turn them back and forth. Otherwise they may start to sound scratchy when you turn them if that white crud get's between the wiper and carbon track.

[southpaw219]

Originally Posted by jonesy

I you decide to keep those CTS pots they make different types of electrical contact cleaner that you can spray down into those pots and that should remove the oxidation. Spray it down into the shafts and turn them back and forth. Otherwise they may start to sound scratchy when you turn them if that white crud get's between the wiper and carbon track.

Ah-ha. The pots were definitely scratchy when turned. Now I know why.

Is there any contact cleaner you'd recommend by name? Are they more or less all the same?

Cheers.

[jonesy]

Originally Posted by southpaw219

Ah-ha. The pots were definitely scratchy when turned. Now I know why.

Is there any contact cleaner you'd recommend by name? Are they more or less all the same?

Cheers.

The pots can be scratchy from the oxidation in between the wiper and track, but they can also be scratchy because the carbon track is wearing out. So if you clean them and they are still noisy when you turn them then you will need to replace them.

I have been using Blow Off Contact cleaner for years and it works good, it drys quickly and does not leave any oily residue. They also make a Duster that just sprays air, but that is not what you want for cleaning pots. Also never use anything like WD 40 for cleaning pots, all it will do is attract dust and dirt and make even more of a mess inside the case.Blow Off 11oz Regular Contact Cleaner | Edmund Scientific

[southpaw219]

Originally Posted by jonesy

The pots can be scratchy from the oxidation in between the wiper and track, but they can also be scratchy because the carbon track is wearing out. So if you clean them and they are still noisy when you turn them then you will need to replace them.

Is there a rudimentary circuit I could rig that allows me to send a signal to my amp to test whether the pot is scratchy once cleaned? Without soldering them back into the guitar?

I'd like to be able to do the test before re-installing the pots in my guitar and then, potentially, having to remove them again, if it proves to be the track that is the problem.

Thanks a million.

[jonesy]

Originally Posted by southpaw219

Is there a rudimentary circuit I could rig that allows me to send a signal to my amp to test whether the pot is scratchy once cleaned? Without soldering them back into the guitar?

I'd like to be able to do the test before re-installing the pots in my guitar and then, potentially, having to remove them again, if it proves to be the track that is the problem.

Thanks a million.

You could wire up some alligator clips onto one of your pu leads and then another set of clips with an output jack wired to the end. That way you could test each pot out individually without the rest of the circuit to see how they work after you clean them.

Your welcome, glad to help.

[SGguy]

Jonesy, I got a buzz problem. If I touch anything metal on or in the guitar, ANYTHING, my annoying buzz goes away. And for some reason, my neck pup still works even though the braided shield is not soldered. and finally if I touch the stud in the humbucker the buzzing gets louder. I'm confused as H E double hockey sticks.

[jonesy]

Try soldering the braided ground on the pu lead to the back of the volume pot and see if things quiet down.

[SGguy]

no dice, I did however notice that if I get my finger close to the wire coming from the vol pot to the switch it starts buzzing more. I have melted the cover on that one a tad so I think I'll put some electrical tape on it to aid with the shielding.

[southpaw219]

Originally Posted by chensi

THANK YOU
i think i should thank you very much for you can waste lot of time to write this post .....thank you again for your sharing..

Just a little info ... telling someone they're "wasting their time" to do anything sounds a little insulting, even if it's not intended to be.

[Giant]

Originally Posted by southpaw219

Just a little info ... telling someone they're "wasting their time" to do anything sounds a little insulting, even if it's not intended to be.

I think that posters first language may not be English. He wrote "i think i should thank you very much for you can waste lot of time to write this post .....thank you again for your sharing..
I think its supposed to read "Thank you for taking the time to write this post. Thanks again for sharing..."

I could be wrong, but it just seems like a language thing.

[southpaw219]

Originally Posted by Giant

I think that posters first language may not be English.

Yeah, it seems pretty apparent that's an English as a Second Language posting, but I don't think that invalidates my pointer that, idiomatically, there are phrases to avoid when posting in said second language.

I speak a few languages, and I've always been grateful when people inform me of things NOT to say, or how to say something more politely / appropriately. So, I'm just paying it forward.

[ToneQuest75]

Is the ground wire from the tailpiece to the cavity in a Les Paul really necessary? I mean, is it important from a safety point of view? The way I see it, the guitar is safer without it - since it makes a connection between the strings and the electronics circuit via the tailpiece, so potentially the strings could become live if there were a problem. Surely the guitar is safer without it, since wood is a good insulating material anyway. Or am I missing something?

[jonesy]

Originally Posted by ToneQuest75

Is the ground wire from the tailpiece to the cavity in a Les Paul really necessary? I mean, is it important from a safety point of view? The way I see it, the guitar is safer without it - since it makes a connection between the strings and the electronics circuit via the tailpiece, so potentially the strings could become live if there were a problem. Surely the guitar is safer without it, since wood is a good insulating material anyway. Or am I missing something?

99% of guitars have a ground wire from the tailpiece to the wiring harness. It does help keep things quieter. I just upgraded a 1978 LP and it did not have the ground wire. After playing on it I think it would have been better off with one in my opinion.

If you are worried about getting shocked from your amp or pa you can add in a capacitor in series and it will block any AC current trying to get through.

[ToneQuest75]

Originally Posted by jonesy

99% of guitars have a ground wire from the tailpiece to the wiring harness. It does help keep things quieter. I just upgraded a 1978 LP and it did not have the ground wire. After playing on it I think it would have been better off with one in my opinion.

If you are worried about getting shocked from your amp or pa you can add in a capacitor in series and it will block any AC current trying to get through.

That's interesting, because I agree in theory it should help keep things quieter, but the funny thing is, I have excessive hum on my Orville by Gibson LP, and in trying to reduce the amount of hum, I unsoldered the ground wire and the hum was dramatically reduced (though not totally eliminated).

[jonesy]

Originally Posted by ToneQuest75

That's interesting, because I agree in theory it should help keep things quieter, but the funny thing is, I have excessive hum on my Orville by Gibson LP, and in trying to reduce the amount of hum, I unsoldered the ground wire and the hum was dramatically reduced (though not totally eliminated).

I have heard a theory where some people bodies act as an antenna and actually add noise into the guitar. But not sure if that is really true or not. I know you act as a ground when you touch the strings.

Hum or buzz comes from bad soldering, improper grounding or a partial short somewhere in the circuit or pickups.

[JakeDSL]

Originally Posted by jonesy

I hope this new guy takes care of you and does a good job, but to be honest if you can learn to work on your own guitars you will not only save money but you won't have to leave them with somebody else and it may save you headaches in the long run.

I understand that not everyone feels comfortable working on a $2000 LP, but I think it is important to try and do as much as you can. The more you do, the more confidence you will have and there is also a sense of pride that you will get from working on your own guitar.

Working (soldering is extreme;y tedious and difficult work.) Trust me, I've tried learning from this and other forums for years now, and there is a magic and talent to it. You can't just learn how to do this. It takes many many many hours of trial and (mostly) failure as well as hands on guidance from an experienced pro. You cannot just learn to fix a guitar over the Internet. Period. There are many things that must be learned and discussed that only can arrive from a human element involved in your learning process.

[jonesy]

Originally Posted by JakeDSL

Working (soldering is extreme;y tedious and difficult work.) Trust me, I've tried learning from this and other forums for years now, and there is a magic and talent to it. You can't just learn how to do this. It takes many many many hours of trial and (mostly) failure as well as hands on guidance from an experienced pro. You cannot just learn to fix a guitar over the Internet. Period. There are many things that must be learned and discussed that only can arrive from a human element involved in your learning process.

Soldering up guitar wiring and other components is not rocket science or "magic" and there is definitely some skill involved. And like anything the more you practice and spend time learning about it the better you get at it.

I have had dozens of people with minimal experience purchase harnesses and DIY kits from me an successfully installed and assembled their own wiring and pickups. True enough that some people are just not cut out for this type of thing, but many are. Sounds like maybe you have had problems and are speaking more from personal experience, but you shouldn't discourage those that are willing to try.

[SuiteAmpCo]

I just iinstalled a new harness in my SG. I used the RS 50's wiring scheme (very clean and easy to do). I shielded the cavity 100% with copper tape with condujctive adhesive. Since this took a lot of small pieces to cover gaps I ran a braided ground sleave and soldered it to the tape inbetween the pickups and to the back of the neck vol pot. I get ground continuity like a dream anywhere on the guitar (a tuning post to a comparment cover screw). I took the ground wire from the tailpiece and used it to wrap and sorta wire tie my pickup leads (2 wire, inner wire & braided ground). That is how I found it when I opened the electronics compartment, so I gave it the same purpose when I rewired it.
So far the guitar is DEAD quiet. Even with my crappiest practice equipment its noiseless. Should I solder the tailpiece ground wire to my jack or one of the pots? Or leave it? I did notice a hum before I replaced the wiring when I lifted me hands from the strings. Is this the result of a bad tailpiece ground? Btw its a Gibson Faded Special SG (lil $700 model) with big boy electronics in it now.

[jonesy]

The ground wire to the tail piece studs normally solders to the back of the neck volume pot in SG's. They way that ground works is, when it is connected properly any slight noise will be gone when you touch the strings. So sounds like it was connected and working fine before the re-wire.

[guitarnut_germany]

5.) If you have a bad ground aka "buzzz" and your guitar is noisy it is most likely due to either a poor solder connection, partial short or dirty ac power.

I have buzz and hum, even when the guitar is not plugged in. When I touch the metal part of the plugged in cable jack, not the tip (cable is plugged into the amp but NOT the guitar), OR any metal part on the amp, the buzz is GONE. Does that mean I have dirty AC power??

I checked the connection from bridge to jack on the guitar with a multimeter and it sems ok. I think the guitar itself is grounded ok.

This has been really frustrating for me!

cheers

[jonesy]

Originally Posted by guitarnut_germany

I have buzz and hum, even when the guitar is not plugged in. When I touch the metal part of the plugged in cable jack, not the tip (cable is plugged into the amp but NOT the guitar), OR any metal part on the amp, the buzz is GONE. Does that mean I have dirty AC power??

I checked the connection from bridge to jack on the guitar with a multimeter and it sems ok. I think the guitar itself is grounded ok.

This has been really frustrating for me!

cheers

Hard to say exactly but maybe pickup an outlet tester like this and see if your outlet is properly grounded. The humm could also be from another source like a computer or dimmer switch etc. Or you may have a tube going bad or faulty power transformer in your amp?

[guitarnut_germany]

I tried my other amp at home, there was still a slight buzz, but nowhere near the buzz I had with my mesa stiletto in our practice room. It's a really old building there and I suspect the AC power might be bad there.... I'll try the stiletto at home for a comparison!

[goldtop56]

ok so i am about to start wiring my epiphone 56gt like they did in the 50s im pretty new to wiring guitars so was hoping someone could give me a wiring diagram that is simple to follow i have got 2 PIO caps a .22 and a .15 i have got gibson braided wiring some cloth covered wire i will be using the stock pots switch and jack as i wanted to see what difference the 50s wiring had first, so hopefully someone will be able to help me

[pmonk]

I have developed a pretty bad buzz on my 1975 Deluxe which was post-factory routed for full HB.

The original pots where replaced with 500k pots. It was fine when first done, but it was int he closet for a few months then when I plugged her in I get a horrible buzz that goes away when I (1) touch the metal casing of the guitar cord (2) touch the metal screws on the pup rings, or (3) touch any metal with my foot?

Do I need to re-do the soldering?