Author Topic: Shielding a scratchplate. (Read 6136 times)

gingataff · « **on:** August 12, 2007, 09:25:44 AM »

I have a strat type guitar with no shielding so I plan to use aluminium tape on the back of the scratchplate. I know strats usually have the tape only on the area where the pots and switch are, it it worth covering the whole of the back of the plate? Secondly do I need to solder an earth to the tape?
Cheers.

WezV · « **Reply #1 on:** August 12, 2007, 09:36:17 AM »

have you read this thing about shield strats:
http://www.guitarnuts.com/wiring/shielding/shield3.php

No problems with sheilding the whole thing but you might want to go further and shield all the cavities as well.

You dont need to solder a wire to the scratchplate because the controls will make that connection for you when they are attached.

gingataff · « **Reply #2 on:** August 12, 2007, 09:48:09 AM »

Cheers Wez, that's a great link.
Some of it is a bit more techy than I was planning, but seeing as my guitar is a single humbucker I think just shielding will be enough. I'll definatey try the cavities as well, although I usually see copper used for this, will aluminium be ok?

WezV · « **Reply #3 on:** August 12, 2007, 10:01:43 AM »

copper is easier to use but aluminium works fine. if you do the cavities leave a little coming over the top that will connect with your scratchplate shielding

The important thing is to remove the shielding wire that will already be going between the pots because the aluminium will now be doing its job and if left in place you will get ground loops which will cause more noise and a hell of a lot of frustration!!

That link is a bit techyfied and to be honest i think its a little overkill for most of us - but using some of the techniques mentioned will help a lot

Philly Q · « **Reply #4 on:** August 12, 2007, 01:13:37 PM »

I can't claim to be an electronics wizard, but I'm not convinced by all that stuff about star grounding and ground loops. People like Hamer and Fender use cavity shielding foil/paint and still have wires connecting the pots together, and I don't believe they're idiots. All those wires and pot chassis ultimately connect to a common ground on the output jack.

I think the star-grounding stuff is much more relevant to complex circuits like amps. The Guitarnuts chap himself says this at the very bottom of the article:

"The star-grounding presented here is important more for protection against white noise and radio interference than 60hz hum. If your guitar came from the factory with foil on the back of the pickguard and a heavy layer of shielding paint in the body cavity then following these instructions for the star grounding is probably only going to give you a barely perceptible reduction in hum."

For my two-penn'orth, I like to use copper foil on the back of scratchplates and conductive paint in cavities. Foil-lining the cavities probably works better (and is cheaper), but it's fiddly to work with, and making the electrical connections when you have to use more than one piece is a pain. And that stuff has bloody sharp edges! :x

WezV · « **Reply #5 on:** August 12, 2007, 03:53:11 PM »

yep, a lot of fuss is made over sheilding and some may be overkill.

but ground loops do happen and can be very annoying - thats when it makes sense to start star-grounding and remove the other ground wires.

I dont do all my ground wires to one lug screwed into the side of the cavity but they usually all go to one pot!

oh, the last fender i took apart (a custom shop jazz bass) was star grounded to the conductive paint in the cavity

Philly Q · « **Reply #6 on:** August 12, 2007, 04:04:29 PM »

I've got a couple of newer Fender Tele bodies which are routed for a neck HB, middle SC and bridge SC. All the cavities have conductive paint, connected by a series of lugs screwed to the bottom of each cavity then grounded to the volume pot. It's very neat - so different from Gibson!