Grateful Dead Music Forum

A place to talk about the music of the Grateful Dead 

 #87160  by gdrfk1990
 Sat Sep 25, 2010 3:06 pm
Is this reccomended in the cavity if using Humbuckers or should the Humbuckers be silent anyway ???
 #87163  by strumminsix
 Sun Sep 26, 2010 11:46 am
Shielding also impacts tone so keep that in mind. I go unshielded and simply roll off my volume between songs in noisy rooms.
 #87388  by Rick Turner
 Fri Oct 01, 2010 8:03 am
Shielding should not negatively affect tone if done correctly. Yes, there can be an issue with capacitance, but unless you put insulated hot leads right on the shielding or cram shielding around pickup coils, it's negligible, and even in those cases, I doubt you'd really hear much. Pickup covers are a different issue due to eddy currents, and that's a whole subject unto itself.

Inside the guitars we started with making sheet copper boxes soldered together. Then we went to silver conductive paint, tried copper paint and didn't like it, and now I mostly use ElectroDag carbon shielding paint.

One of the biggest issues is incorrectly or not grounding the shielding, as ridiculous as that may seem, I've seen it many times. It just makes the problems worse.

Also, you should try to star ground all guitar electric components for lowest hum and buzz pickup.
 #87407  by USBLUES
 Fri Oct 01, 2010 10:51 am
Is copper shielding just for the cavity? What about the pickup area do you need any in there ?
 #87425  by Rick Turner
 Fri Oct 01, 2010 1:23 pm
I do shield pickup cavities. Often pickups will have unshielded connections on the bottom, particularly traditional single coil pickups. Your body will act as an antenna for noise and literally radiate it into unshielded wires in the guitar. If you can put your finger on a metal part of the output jack area and reduce noise, that's a shielding inadequacy.

Unless you are being careless about stray capacitance issues, I think too much shielding is usually not quite enough.

Bear in mind that there are two sources of hum and buzz...electromagnetic fields which can be dealt with via humbucking or humcancelling pickups and coils...and electrostatic AC fields which can be dealt with via proper shielding. Then there is the issue of ground loops acting as coils and picking up electromagnetic radiation. This is why you should not loop ground connections from pot to pot to point. Every grounded component should have it's own green color coded wire to a central ground point that is connected to output connector ground. Google "Star grounding" for complete info.
 #87511  by Rick Turner
 Sun Oct 03, 2010 10:37 am
I have found star grounding in guitars to be helpful in all cases, and in fact it is essential if you have active electronics on board. The jack ground does become the hub. If you can get away without star grounding, more power to you.
 #87543  by Rick Turner
 Mon Oct 04, 2010 10:37 am
If one confuses shielding for grounding points, then you've got an issue.

I don't. Shields should be grounded to your "star" point, or buss, too.

What I do and how I do it is based on what works in my guitars and what doesn't seem to work in many others. There are several ways to skin this cat; I've developed my own take on it, and it works. To dismiss star grounding out of hand I think is to do other luthiers a disservice. There are far too many hum and buzz ridden guitars out there that could be greatly helped by decent wiring practice.
 #87570  by Chinarider1A
 Mon Oct 04, 2010 2:17 pm
There seems to be a lot of discussion/confusion regarding this topic. In the area of shielding, is there a proper way to do it to achieve maximum hum reduction? And what material works best? And where do you get it? Any videos?

thanks - dave
 #87576  by Rick Turner
 Mon Oct 04, 2010 3:53 pm
Are you being deliberately disagreeable?

I never said that I used multiple ground paths among components, did I? I keep shielding ground separate from signal grounds, and I don't loop them.

Look, I'm not here to argue these points with you. I do know what I'm doing, and I do use a pretty damned clean star grounding system in my guitars, and it works.

Lighten up...
 #87584  by Rick Turner
 Mon Oct 04, 2010 6:23 pm
I make it a point not to argue with folks who hide behind handles on the Internet and who are flat out rude.

I've been at this electric lutherie game for 42 years now, and I do know what I'm doing.

End of discussion.