Pickup/guitar Shielding...

[Joe Gwinn]

I have experienced similar problems on at least 3 different guitars. Mine have usually involved static charge building up on the pick guard and creating a crackling sound via transfer to the pickups. Not sure if you have a pick guard on this guitar. The pickup shielding & wire insulation may play a role in these problems.

On one guitar I used copper foil to create a sink for static charge on the back of the pickguard and soldered a lead that connected to the cavity ground. On that particular guitar, problem solved! A year later, encountered the same problem on a different guitar and after several weeks of dicking around finally removed the pickguard and, problem solved. The crazy thing is that I have not found one bombproof way of dealing with static crackling issues. Also have spent hours verifying/improving cavity shielding and grounding on these problem guitars without a 100% solution. Years ago purchased about 20 lb of high quality copper foil sheets and whenever I run into problems with noise usually try shielding cavities, attaching foil to pickguards, etc. Most of the time this helps but with some materials (plastics/finishes?) nothing I have tried seems to completely eliminate the problem.

What's happening is that the human is rubbing the pickguard, which causes separation of charges, the human being charged one polarity, the pickguard et al the other polarity. When the voltage becomes sufficient, current flows in a series of little sparks. Your mission is to provide a way for the separated charges to reunite slowly and in silence.

I find that some shirts/sweaters (fabrics) cause more static than others.

The traditional way to generate static electricity was to stroke a piece of amber with a catskin. It doesn't matter if the cat is alive or dead.

A cat walking across a nylon rug works pretty well too. Absolutely perplexes the cat. The spark from the nose hurts.

http://books.google.com/books?id=9dJ...sult#PPA225,M1

Millikan was the first physicist to measure the charge of the electron.

[bbsailor]

Static Discharges In The Audio

What's happening is that the human is rubbing the pickguard, which causes separation of charges, the human being charged one polarity, the pickguard et al the other polarity. When the voltage becomes sufficient, current flows in a series of little sparks. Your mission is to provide a way for the separated charges to reunite slowly and in silence.

The traditional way to generate static electricity was to stroke a piece of amber with a catskin. It doesn't matter if the cat is alive or dead.

A cat walking across a nylon rug works pretty well too. Absolutely perplexes the cat. The spark from the nose hurts.

http://books.google.com/books?id=9dJ...sult#PPA225,M1

Millikan was the first physicist to measure the charge of the electron.

Joe,

A while back I was on a business trip in Berlin, Germany. The hotel had a piano player who used a rhythm machine and sang live through a PA system. Everytime someone walked across the floor there was a "zit-zit-zit"-like sound in the PA. During the piano player's break, I mentioned to him that he was experiencing effects of static discharge due to low humidity. Leather or rubber shoe soles and rug fibers can make a powerful static generator.

I suggested that one quick fix is to obtain a water mist spray bottle and spray the rug path where most people are walking. After another set of PA noise he obtained a spray bottle and did what I suggested and the next set was quiet. I was thanked by being bought a drink for my improvised solution to his audio problem.

This affirms your observation about the effects of static discharge in audio systems.

Joseph Rogowski

[Chadheckler1]

What's happening is that the human is rubbing the pickguard, which causes separation of charges...

This is a paul style guitar with no pickguard...and the static is building up on the back of the guitar where it is rubbing my pant leg/shirt while standing.

Your mission is to provide a way for the separated charges to reunite slowly and in silence.

How do you propose that I accomplish this?

[roundmidnight]

Chadheckler1 - Have you tried playing the guitar with the pickup switch and control cavity covers removed. These may be generating the static when rubbed against your clothes or functioning as a path for the static to reach your control wiring. You might try gluing shielding foil on the inside of one or both of these covers and then figure out a way of routing a little strip of foil with a wire soldered to it and then soldered off to ground. Not really sure if this will work but in several instances this solved pickguard problems for me. Metal covers would work but not sure they are available and are probably not what you are looking for aesthetically.

RM

[Chadheckler1]

RM - At this point I am not concerned about aesthetics. I just want a good understanding of what is happening and how to solve the problem so that I can hopefully prevent it from recurring by changing my design or being proactive...

I have played with the covers off... I also fully shielded the cavities as I stated earlier in this thread and I have good conductivity across the farthest points of the guitar...covers included. The static seems to be building on the lacquer in the center area of the back of the guitar...I can move my finger around on the back and get it to happen.

BTW, you can call me Chad if you want...ChadHeckler1 sounds so formal, HA!

[David King]

Chad,
What about an antistatic spray like this :
http://www.officedepot.com/ddSKU.do?level=SK&id=266951

I see some antistatic treatments for hard surfaces are supposed to work for months at a time. I don't know what's in this stuff.

If you wanted to get all high-tech, you could inlay a grid of very fine wires into the finish to carry away the charge. It doesn't need to be very conductive to work. The electronics industry is constantly fighting static build-up and I'm sure there are off-the-shelf products that would take care of this for a good long time.
Could part of the problem be the guitar case lining?? Have you tried other cases?

[Chadheckler1]

Case... hmmm... I never thought about that but the only two guitars that have this problem are both in the exact same make and model of case that I bought at the same time... I am going to try the anti static spray and stick them in a different case and see what happens.

[Joe Gwinn]

This is a paul style guitar with no pickguard...and the static is building up on the back of the guitar where it is rubbing my pant leg/shirt while standing.

How do you know this? When playing, it has to be hard to rub just one thing.

How do you propose that I accomplish this?

Slowly and carefully?

If the shielding is good, static on the back of the guitar should not matter. When the charges reunite, some of the current is making its way through the signal circuitry. Not having the guitar in hand, it's hard to be more definite.

[Chadheckler1]

[QUOTE=Joe Gwinn;90865]How do you know this? When playing, it has to be hard to rub just one thing.
QUOTE]

I can stop playing, hold the guitar away from my body, and rub my finger/shirt/etc on the middle of the back and cause it to happen. I guess that doesn't mean that is the only place that it is happening though...

If the shielding is good, static on the back of the guitar should not matter. When the charges reunite, some of the current is making its way through the signal circuitry.

This is good to know that I just haven't shielded it well enough... I was under the impression by other posts in this thread that shielding might not ever solve this issue. I will try again.

[roundmidnight]

Chad,

I indicated in an earlier post that I had a couple of problem guitars that I was never able to fully cure of this problem. I think with enough effort you will be successful. Somewhere on your guitar positive and negatively charged surfaces are finding a conductive path through your guitar electronics. I wouldn't think wood would be sufficiently conductive so it must be finding a path on the finish or plastic surfaces to contact your wiring somewhere.

RM

[Chadheckler1]

I'm not giving up...through difficulties come the greatest personal discoveries. The thing that got me hooked on building guitars from scratch was the fact that it is not as easy as seems and you usually encounter something different on each guitar which keeps it interesting. I will find the root cause and the solution eventually...

Adios,
Chad

[David King]

Chad,
How about hand blown glass insulators for your wiring like the old knob and tube style wiring. You could rout very large channels and keep all wires at least 1/2" away from all wood. Also air isn't the best insulator, a vacuum might be better or perhaps a special gas that ionizes in a pretty color then there's a charge present. Heck you could make a neon guitar that's noisy as hell but someone would play it for the color.

[belwar]

Hey Guys,

I'm now in need of buying some shielding paint. Im good with either Aerosol or Brush on. People here talked about the compunds from MG chemicals and was wondering which would be better for guitar shielding purposes. Here are the specs of both

Product #841 - Super Shield - Nickel Flakes.

A general purpose EMI / RFI shielding spray for use on plastic electronics enclosures. Consists of a tough, durable acrylic base pigmented with a high purity nickel flake.

UL Recognized
Shielding effectivieness: One to two mil coating provides 40dB - 50dB shielding across a frequency range of 5 to 1800MHz.
Surface Resistance approx. 0.7 Ohms
Dry time: 10 minutes at room temperature
Recoat time: 5 minutes
Excellent adhesion to most plastics
Available in both liquid and aerosol
Tested as per IEEE Std. 299-1997
Underwriters Laboratories Recognized File No.: E202609

Product #843 Silver Coated Copper Flakes

Reduces or eliminates EMI / RFI interference. A general purpose EMI / RFI shielding for use on plastic electronics enclosures. Consists of a tough, durable acrylic base pigmented with a high purity silver coated copper. Has a resistivity of 0.15 ohms • cm.

So the resistance of the Silver coated copper is lower. I just dont know which one is going to do a more effective job. Any suggestions?

[David King]

Belwar,
I was using the waterbased, silver conductive paint from Spraylat in NY and it's an excellent product but I notice that it does seem to oxidize and darken after a few years. Mostly the shelf life was limited and the minimum order was 1 gallon or $250, I forget which. It was very easy to brush on and clean up afterwards and you could extend the pot life with additional Everclear as it got goopy. I'd have to say that the shielding potential was just about the same but I wasn't testing that in any scientific. The waterbased would not bite into glossy surfaces and that made it useless around over-sprayed cavities. I had to roughen the surface first. The Nickel spray dissolves right into ABS, styrene and acrylic covers so the bond is excellent with no runs.

I think the nickel might be more stable. The nickel is definitely magnetic, something to keep in mind when shielding plastic pickup covers.

[Achiles]

Last week i tryed to mesure the resistence of a 12 years old Alembic control cavity (silver color painting)and it was null,nothing .