Post by hootmeister123 on Oct 5, 2016 10:38:05 GMT -5
I'm getting ready to implement star grounding per John Atchley's scheme, and here's a question: Instead of making the pickguard shield contact the control cavity shield on the top of the guitar body, is it also okay instead to connect them by a single wire? I'm planning to run a soldered wire from the ground lug in the control cavity to a ring terminal screwed underneath one pot. I was thinking this might give better contact than the other method. Is it okay to join the two halves of a Faraday cage like this?
Well that question isn't really about star grounding but we'll get there...
First, I think it's best that the shield is actually physically continuous without any gaps. That's obviously not always possible, but I find myself wondering why you wouldn't just do that. It's a whole lot less messing around than trying to run a wire.
Then, I think this defeats the point of star grounding to an extent. Just run that wire to wherever you're collecting your grounds and be done with it.
Post by hootmeister123 on Oct 5, 2016 11:51:50 GMT -5
I'm using conductive paint for the cavities, and I'd be fine with the usual approach if it's physically continuous without gaps. It seems like the contact between those two planes may not be very reliable, especially in parts of the pickguard that aren't close to a screw site. I agree having the edges touch seems superior in theory, but it's the quality of contact that made me think about other ways.
On the other hand, it sounds like people in this forum have had good success with the overlapped edges approach.
Either we have a good electrical connection between the two parts or we don't. Having more points of contact doesn't make the connection "better".
Ash is right, ideally we want our shielding to be a complete envelope around all the potential noise-gathering items inside it. But that's a separate issue from whether all parts of our shield are grounded properly.
You should check, with a meter, to see that the cavity paint produces continuity across its surface- check several axes. Do the same with the foil on the pickguard. If those items are continuous, then we need only to make contact (reliably) at one point between the two. If one or more screws provide that contact, fine (that contact can also be tested, although it's a little trickier). Or, you can use a washer wired to the grounding point and slipped over the shaft of a pot before the pot is installed- that's the method John Atchley advocated in the original description of his shielding.