Copper shielding - reasons for and against?

[EddieDavis]

Hi

So from what I've read online guitarists will put copper shielding in the cavity to reduce unwanted frequencies from being picked up by the guitar, especially at gigs etc.  where there are lots of variables and unpredictable electronics happening.

And I assume the reason people don't do it is because

A.  They don't feel it's necessary.  And
B.  If you don't do the job correctly you could actually make interference worse. 

Is there anything else?  What are your reasons for or against this optional step in guitar assembly?

Thanks!

 

[Cagey]

In a nutshell, if you have humbucking (or otherwise noiseless) pickups, you don't need it. The pickups are what pick up 98% of the noise you hear, and those are designed to reject it. If you shield the cavities, you might get rid of 1% more.

If you have single coils, no amount of cavity shielding will help. The pickups are outside the shield.

 

[EddieDavis]

If you have single coils, no amount of cavity shielding will help. The pickups are outside the shield.

Sounds like it might be pointless to do it on a strat then...

The order I have in progress is for a strat with single coils and no RW/RP in the pickups. 

 

[Cagey]

No, I'm afraid you're doomed  :laughing7:

Although, some of the newer noise gates are quite effective without being obvious. 

 

[Cagey]

I should add that Bill Lawrence's "Microcoils" and Fishman's new "Fluence" pickups are really good, if you like single coil performance but would rather not have the noise. Also high on the list are GFS'  "TrueCoil" pickups.

 

[stratamania]

Another option for hum with normal single coils.

http://www.ilitchelectronics.com/strat-bpncs-3/

 

[Ace Flibble]

People seem to frequently misunderstand what shielding is for. It's not for cutting out 50/60 hum, it's for reducing the static you get when you touch the surface of the guitar yourself.

Les Paul Juniors are great examples as they're almost never shielded and produce a strong signal. Plug in a LPJ , put your fretting hand on the strings as normal, and then with your picking hand, rub a finger along the front of the guitar. The closer to the pots you go, the more static you'll hear. Rub right around the control pots or pickup and the static will be just as loud if not louder than the 50/60 hum.

If I have time later I can see about recording an example as I happen to have an LPJ which is unshielded and an LP Special which is shielded, to compare. You get audible static through the LPJ (even though it has a humbucker, too) but not through the LPS (which just has P-90s).

Note the effect seems to be worse with nitrocellulose finishes than with either type of poly or any wax or oil finish. They'll all still do it, but nitro is definitely the worst, by far.

Now, I can not pretend to understand the science behind it, because I plain don't. All I know is that every guitar I have which is either shielded (either via tape, paint, or a metal guard) or that has active pickups does not transmit this static; every guitar I have which does not have any kind of shielding and uses passive pickups does make this static effect audible, without exception. The same goes for every guitar I've serviced or put together for anybody else, too. Shielding guitars has become one of my most-common tasks other than the ever-popular pickup replacement.


If you are going to use a poly finish and don't play with much gain, you'll probably be fine without shielding. Since you're using single coils, you're going to have 50/60 hum anyway. Shielding the pickups and controls won't do anything about that hum and you're unlikely to notice any static when the hum is there even louder. But shielding can't hurt, either. If it were my build, I'd be shielding that guitar regardless. (Though if it were my build I'd also be using RW/RP pickups and probably noiseless ones, too; I think it's kinda crazy to be concerned about unwanted noise yet not using at least RW/RP sets.)

 

[Cagey]

You can get rid of that static build-up/discharge by simply putting a conductive sheet on the backside of the pickguard around the controls. Most modern pickguards have that...

Doesn't need to be much - it's just there to act as a static drain. Like you say, it doesn't shield power line hum, it just gets rid of that nasty crackling noise.

 

[JD0x0]

I disagree with statements like "if you have humbuckers you dont need it." and "single coils wont be shielded effectively because they are outside the shielding"
I dont believe either of these are true. Humbuckers can certainly pick up outside interference. 50/60hz hum wont be there, though.

Single coils definitely benefit from shielding and if you do it right most of the coil will be protected. but... shielding does NOT kill 60hz hum. It kills other things, for example interference from neon and fluorescent lights. Apparently Aluminum works extremely well for noise created by 'dimmer' switches installed in buildings.

My guitars are all shielded and very quiet. I absolutely despise noise gates in my signal chain. I play much too lightly and always notice it effecting my notes too much.

 

[Cagey]

Fortunately, it doesn't matter if you believe it or not. It's simply, empirically, and provably true. Laws of physics, experience of the masses, naked reality and all that fun stuff  :laughing7:

 

[ghotiphry]

The place where I used to play at home had overhead fluorescent light fixtures.  I went through the whole shielding process, and still had this nasty, loud hum.  I'm like, what the heck is going on here.  Then I moved to the basement.  Voila, problem solved.  Haven't shielded anything newer after the change in venue, but haven't needed too either.

 

[mayfly]

You can get rid of that static build-up/discharge by simply putting a conductive sheet on the backside of the pickguard around the controls. Most modern pickguards have that...

Doesn't need to be much - it's just there to act as a static drain. Like you say, it doesn't shield power line hum, it just gets rid of that nasty crackling noise.

Yep.  I've done this with my (un-shielded) telecasters.  With static, it just gives a ground plane for the static to discharge into (instead of into the hot lead of your pickup).  It's not really an EMI thing.  We might be splitting hairs here (for a guitar forum and all), but as it only covers one plane it's not really shielding.

 

[BigSteve22]

Fortunately, it doesn't matter if you believe it or not. It's simply, empirically, and provably true. Laws of physics, experience of the masses, naked reality and all that fun stuff  :laughing7: