Grounding????

[Golfxzq]

After posing a question about a bit of Aluminum that I noticed in the "SRV Project Diary" I was curios, so I began to to some research on the internet. I suspected that this foil was for shielding purposes, so that is where I started my search. It seems that this is quite the topic in some other forums. From my research I have concluded that copper foil is the best material to use, not Aluminum and most forums recommend a total encasement of every body cavity and the back of the pick guard with continuity throughout and a connection to ground.

There is some disagreement as to whether you have to remove the ground wires from the back of the pots. Some say that this is necessary in order to eliminate ground loops but I found one article that said that it is a wast of time because with the common input jack ground you have a "star" ground anyway.

Most folks seem to think that this is helpful in reducing noise when using single coil pickups. How about with Humbuckers, is it necessary?

This topic is new to me but may be an old subject to you builders so I would like to know what you think of the idea. How about it, any opinions either way? Has anyone actually added this to their guitar and did it help? As some of you know, Aggiefan and I are rebuilding a Les Paul copy and I was wondering if we should add this feature before installing all the electronics. Also, I have a Carlo Robelli which sings like a banchie unless I am touching the strings, maybe this would help her as well?

Thanks...

[VikingBlues]

Aggiefan and I are rebuilding a Les Paul copy and I was wondering if we should add this feature before installing all the electronics.

I believe that shielding shouldn't be an issue on a Les Paul copy as long as the ground wires are connected well and the wires are shielded wires. The humbucker pickups are designed so as to "buck hum" and avoid the nasty buzzing single coil pickup issues.

Well, that at least is what I've found so far - any buzzing noises with humbucker guitars have been relating to faulty wiring issues rather than shielding issues. I've never had interference noise on my Tokai or Hagstrom humbucker guitars whether day or night (all the lights on) and whether standing near TVs or computers.

But you're right - it's a huge big discussion area on forums for strat type guitars. Fortunately I like the positions 2 & 4 on a strat so much at the moment I'm avoiding the issue by rarely using the basic buzzing single coil settings of 1,3 & 5. I believe 2 & 4 are less of an issue due to the interaction of the reverse wound middle pup with the others. I know that using 1,3 & 5 at night when lights are on makes the strat noticably "buzzier" than during the daylight hours.

[bluesblooded]

I believe that shielding shouldn't be an issue on a Les Paul copy as long as the ground wires are connected well and the wires are shielded wires. The humbucker pickups are designed so as to "buck hum" and avoid the nasty buzzing single coil pickup issues.

I agree with VB here. You dont need to shield if you only have humbuckers.

The whole copper foil thing is probably good if you gig a lot and suffer from hum. Otherwise, I would not do it.

[Golfxzq]

Thanks VB and Bluesblooded... since the pickups for the LP will be humbuckers I won't worry about all this shielding. The next time I change strings on my Carlo Robelli I'll take a peek inside just to see how (if?) it is grounded. This shielding may be something I will have to give a try on that guitar, it buzzes on all five settings. The buzzing either totally, or almost totally, goes away if I touch the strings, the bridge or the input jack. Sounds like a grounding problem to me. I have read that faulty cables can cause this problem but I have played this guitar with three different cables all with the same results.

Thanks again for the input, fella's...

[bluesblooded]

it buzzes on all five settings. The buzzing either totally, or almost totally, goes away if I touch the strings, the bridge or the input jack. Sounds like a grounding problem to me. I have read that faulty cables can cause this problem but I have played this guitar with three different cables all with the same results.

You probably have a bad solder somewhere. I would bet on the jack itself.

I know nothing about Carlo Robelli guitars. Do you know if the middle pickups is Reverse Wound Reverse Polarity? If so, your buzzing is surely caused by a faulty wire. Otherwise,if it is not RWRP, I believe it would be normal for your guitar to buzz on all 5 position

[VikingBlues]

it buzzes on all five settings. The buzzing either totally, or almost totally, goes away if I touch the strings, the bridge or the input jack. Sounds like a grounding problem to me. I have read that faulty cables can cause this problem but I have played this guitar with three different cables all with the same results.

You probably have a bad solder somewhere. I would bet on the jack itself.

I know nothing about Carlo Robelli guitars. Do you know if the middle pickups is Reverse Wound Reverse Polarity? If so, your buzzing is surely caused by a faulty wire. Otherwise,if it is not RWRP, I believe it would be normal for your guitar to buzz on all 5 position

I believe that is correct - it's only if the middle pickup is reverse wound/polarity you get the hum cancelling in positions 2 & 4 - otherwise all will buzz in a similar way depending on quality of wiring and shielding and how much electrical stuff is zapping around the place around you. How you can tell if a pup is RWRP I don't know I'm afraid. Could be a grounding AND shielding issue of course.....sorry!

[bluesblooded]

How you can tell if a pup is RWRP I don't know I'm afraid.

I don't know either, but here's a thread on tdpri that you could try
http://www.tdpri.com/forum/just-pickups ... arity.html

[Golfxzq]

You probably have a bad solder somewhere. I would bet on the jack itself.

Thanks BluesBlooded... I'll certainly look for that when I get it apart. This is an inexpensive guitar, one that I carry around because I don't want to take a chance with my Ibanez. I bought it used but seems to have been well taken care of. It's probably not made of top quality parts but has some really good reviews for a starter guitar.

I have no idea if the single coils are RWRP, I'll check out your link and see what it says. Not sure what I could do about it except replace the pups... not really worth that I don't think. However, if there is something that I can do like re-solder some joints or add the shielding foil I could manage that.

.... depending on quality of wiring and shielding and how much electrical stuff is zapping around the place around you.

Probably right about the wiring. I'll check to see if the wiring is shielded or not, could be a simple fix right there. The reason that I don't really think it's the in-situ electrical stuff because I carry this guitar around a lot... on vacation, at home, to lessons, I even play it in the car sitting in a parking lot and it always seems to have this problem. However, sometimes it seems to worse than others. So, maybe...

[cruisemates]

I think it is probably a good idea to add shielding foil to a guitar, copper and silver are the best conductors so they are probably the best shields, too.

I would never try to ground and entire guitar to earth through the cabling, though. That is a vast exercise in futility. They say it is enough just to make sure the bridge is connected to the ground.

Having worked in recording studios we dealt with a lot of grounding issues. A "floating ground" is perfectly acceptable - where you just make sure the negatives are all connected - to some kind of shield if necessary, but not necessarily.

If you have a guitar that makes noise try these things: a humming guitar is picking up radio frequency static (called "RF"). You are an antenna.

Try rotating your body , so your guitar is facing a different direction - this is usually the easist and most effective solution. Get a better quality guitar cable - shorter and with more shielding. Try a a ground lift on the amp, or take one off (a ground lift is that little adaptor that makes three prong AC plugs into 2-prong. They usually have a wire hanging from them). Many amps used to have ground switches.

You can try going through a direct box that has a polarity switch (this is a ground lift for the guitar cabling).

Or last - buy a better guitar. My cheap Squire bass has a bad hum - especially around light dimmers and flourescent lights. Rolling off the treble on the tone knob usually reduces it a lot. But also facing south instead of east also fixes it.

And yeah, humbuckers are called that because they buck the hum of RF. Its a well-known problem. The two pickups are wired out of phase with each other so the current is traveling in opposite directions inside each pickup - so they cancel the hum in each other. Pretty ingenious. You cannot have a humbucking single coil pickup.

Sometimes older pickups' wiring gets loose - then you have real problems. The wrappings will vibrate and actually feed back - causing a horrible squeal. I have a Melody Maker with that problem. This is one reason why you should never try to take a pickup apart.

[HalfBlindLefty]

I think it is probably a good idea to add shielding foil to a guitar, copper and silver are the best conductors so they are probably the best shields, too.

I would never try to ground and entire guitar to earth through the cabling, though. That is a vast exercise in futility. They say it is enough just to make sure the bridge is connected to the ground.

I agree.

Remember when you use Elixir strings, there is a catch... the thin layer that makes the strings last longer and feel smoother, can play tricks with you (over time) one second there is no hum... another one there is. At least on my strat it does.

how long I use a set of strings ?... 1 to 2 years..... really

[HalfBlindLefty]

Sometimes older pickups' wiring gets loose - then you have real problems. The wrappings will vibrate and actually feed back - causing a horrible squeal. I have a Melody Maker with that problem. This is one reason why you should never try to take a pickup apart.

I had that same problem with an old Dimarzio pickup.. I wax potted (right term ? ) it again and presto, problem gone
Since it was an old pickup I used candle wax.

http://www.guitarnuts.com/technical/ele ... /index.php

[Golfxzq]

Try a a ground lift on the amp, or take one off...

Taking one off makes since to me, but to add one? That seems like it would eliminate the ground entirely. It also sounds like it could be a safety concern if your amp happened to short out.

Or last - buy a better guitar

Now THERE is probably the solution. My Carlo Robelli is strictly a beginners guitar... can be had for under $100 brand new. But, I still like it so I am going to see what I can do. Maybe adding some shielding and checking the grounding wire connections inside the guitar could solve (or at least help) my problem. I have an Ibanez with humbuckers so I could play that but I just like the "Strat sound" of the single coils so I will do what I can to help the situation.

Remember when you use Elixir strings, there is a catch... the thin layer that makes the strings last longer and feel smoother, can play tricks with you (over time) one second there is no hum... another one there is. At least on my strat it does.

Now that is interesting... Do you think it is because of the coating? If so, I guess this could happen with any coated type strings. Wonder why this is? Maybe the coating wearing off? It seems that if that were the case it would hum with new strings and not when the string coating wore down. I am thinking maybe the coating is insulating your hands from being the ground but as it wore off you would get better grounding? Just speculating here, I don't know. It sounds like a strange phenomenon.

cruisemates wrote:
Sometimes older pickups' wiring gets loose - then you have real problems. The wrappings will vibrate and actually feed back - causing a horrible squeal. I have a Melody Maker with that problem. This is one reason why you should never try to take a pickup apart.

I had that same problem with an old Dimarzio pickup.. I wax potted (right term ? ) it again and presto, problem gone
Since it was an old pickup I used candle wax.

I read about waxing the coils when I was researching shielding and grounding. Doesn't seem too difficult, just have to be careful. I wasn't sure at the time why it was done. I guess it was to stabilize loose windings?

Thanks guys... all very interesting and helpful information... as usual.

[VikingBlues]

I've seen this said on the tdpri forum:-
"if you're using coated strings they can disrupt your connection to ground since the metal of the string doesn't directly contact any metal surfaces on your guitar".

Now, I know very well I don't have the knowledge to judge if this is valid or not - I just throw it in for what it's worth.

[HalfBlindLefty]

Maybe I should have mentioned it earlier...
I tested the string to ground resistance with both an analog and a digital multimeter and there are astonishing differences between different spots on each string.
It's going from high to almost zero ohm values.

So I know but still like the strings :)

[VikingBlues]

This is intersting to know.

Sandra and I have Elixirs on our acoustic and it sounds much better with them on it. When she had an electric for a while she liked elixirs on that too (and they sounded really good) but it was a humbucker guitar, so hum less of an issue.

I've meant to try Elixirs on my electrics sometime, but never got round to it. Not sure about risking them with single coils in view of this discussion.

I did once try coated strings on the Tokai on a whim (not Elixirs - I saw these other ones in a shop and had a moment of weakness). They sucked the tone out of it and all the brightness disappeared - total contrast to the elixirs on Sandra's electric which were tonally very impressive.

[Golfxzq]

That is very interesting. I have coated Elixirs on my Carlo Robelli, except for the high E which I broke and replaced with an Ernie Ball. When I get back home next week I think I'll just change my strings to non-coated strings. While the strings are off I guess I should check out the solder joints and maybe add a little shielding... uh-oh... this is starting to get complicated again.

Anyway, changing the strings may be all I need.

Thanks

[Golfxzq]

Hi guys... thought I would give you an update on this thread...

Remember when you use Elixir strings, there is a catch... the thin layer that makes the strings last longer and feel smoother, can play tricks with you (over time) one second there is no hum... another one there is. At least on my strat it does.

Well I finally bought some EB Slinky's for the Carlo Robelli to replace the Elixir's. While the strings were off I pulled the pickguard and checked out the grounding... all looked solid and well grounded. It had the standard bit of aluminum shielding stuck on the back of the pickguard. I considered adding all that copper foil stuff to the inside of every cavity but decided, with the Les Paul project going on I didn't want to get into that just now so I closed her back up. Then I changed the coated Elixir's to EB's.

Then I tried it and... sure enough not nearly as much hum as before, not all gone, but definitely less... I was excited. Then, a couple of days later, I went to a lesson and she hummed like a hive of bees in a mimosa tree. I asked my instructor about it and he said that it was probably the lights or maybe the cheep amp. Sure enough, the room had florescent lights all over it... strange set up for a guitar studio. His guitar didn't hum but he was using a different amp and was a better guitar. Next lesson I think I will ask him if I could plug into his amp just to see if that makes a difference.

So... problem lessened but not resolved. As soon as the LP is finished (very soon now) I may have to add that copper shielding.... or maybe I could just take my lesson in the dark!