How much shielding is too much ? ?

[Novatuc]

Hi all, I am rebuilding a Strat clone to hopefully be bigger and better. My question is, how much shielding is too much shielding? I have come into a small supply of adhesive back copper sheet that I am going to use for the shielding. Should I just go to town? I am looking at doing all body cavities and the entire back of the pickguard. Is that a wasted of the the copper? The power supply is pretty crappy here so I only use humbuckers to begin with.

 

[PixelMover]

IMO - the pickup cavities is all you need.

Or you can really go to town - looks like this guy's pickups were far too powerful...

image removed

 

[still_fiddlin]

I think the PU cavities and PG should be shielded. That's what I did, and mine is very quiet.

But, to answer the topic question, I don't think there's "too much" but you can probably waste some time and material, i.e., at some point it's not going to make a difference.

Check your guitar cables while you are at it. Bad shielding on those can be a worse source than the PUs.

 

[StootMonster]

OK, so all this time I thought the buzz and noise was just a trait of the single p/u. Shielding can eliminate this?

 

[j.vasek]

As others have said, shielding the pickguard and pup cavities should be all you need. Just be sure that you have a solid connection between the pieces of copper tape (via soldering edges).

I've heard some people state they noticed a loss of some of the higher frequencies when they shielded their guitars. I've noticed no such phenomenon, but it may be more noticeable with different setups, pickups, amps, etc.

 

[still_fiddlin]

Shielding can reduce significantly the kind of noise that is introduced externally, e.g. electro-magnetic-field (EMF) induced. Basically, that kind of radiation causes the pickups (and any unshielded wire that could act like a pickup) to generate a sound/noise.

If the noise is already in the circuit, e.g., picked up by some other unshielded component, shielding your guitar won't help.

Humbuckers work because the two pickups (i.e., halves of the single hb) are out of phase, so when they both generate the noise signal, it's out of phase, and when they are joined together, the noise part of the signal (along with other stuff!) is canceled.

I'm sure there are technical folks who can provide graphs and formulae if necessary .

 

[woodman]

OK, so all this time I thought the buzz and noise was just a trait of the single p/u. Shielding can eliminate this?

in my experience, shielding can help, but will never stop all the noise from single-coils — it's the nature of the beast. as Terry Downs explained a while back, a single-coil is basically an antenna!

 

[DocG]

in my experience, shielding can help, but will never stop all the noise from single-coils — it's the nature of the beast. as Terry Downs explained a while back, a single-coil is basically an antenna!

Terry is a god among men. The shielding does keep a high percentage of the unwanted electrical noise from hitting the antenna, er, pickup coil. The pickup + string combination is basically a tiny generator as well as an antenna. Plus it's a floor wax and a dessert topping!

By the way, to clarify still_fiddlin's note that

Humbuckers work because the two pickups (i.e., halves of the single hb) are out of phase, so when they both generate the noise signal, it's out of phase

both the windings and the magnetic polarities are out of phase, so only the hum is bucked. If it were just one or the other, the signal would get cancelled too. Some middle Strat pickups are reverse-wound reverse-polarity, so that middle+neck and middle+bridge positions are hum-cancelling.

 

[Novatuc]

Thanks for the replies everybody. I'll just do the regular shielding of the cavities and a little patch on the back of the pickguard by the controls. I don't want to waste the pretty copper foil for nothing gained. There will always be another project in need of some.

 

[still_fiddlin]

So, I've always wondered about the control thing. If it's the pickups that are acting as antennae, why shield the controls?

Me, I'd do everything. If you don't cover the PG so that it covers the PU cavities, then you've left a gap. Think a "U" over (under) the PU. Particularly if you've got a HB size cavity. That's a lot of unshieded space at the front, and you're only blocking radiation coming through the back - i.e., whatever is passing through your innards. Just my $.02.

P.S.

Some middle Strat pickups are reverse-wound reverse-polarity, so that middle+neck and middle+bridge positions are hum-cancelling.

My middle PU is not RWRP, and still very quiet in 2/4. But, this does raise an interesting test case. If your PUs are the source of [generating] a lot of noise, and you have RWRP, then 2/4 should be a lot quieter than 1/3/5, without any additional shielding, since you're effectively, creating a humbucker. If your PUs are *not* RWRP, then 2/4 should be a lot noiser than 1-3-5, because the noise part of the signal is added together. If you don't hear any difference (and it depends a lot on where you are playing/standing), then shielding isn't likely to do much, either, because there's noise getting in somewhere else.

 

[Okieactor]

On my Jimmie Vaughan Strat the 2/4 positions are MUCH quieter than the 1/3/5. I think this is the case on a lot of strats. But there may be some out there that are not.
I don't tend to use the 4 position very much, but the 2 (front + mid) sounds very good.

 

[qblue]

I know that most Strat Pluses and Ultras with a 'swimming pool ' route area are shielded w/ conductive paint. So that helps.

Humbuckers shouldn't need shielding unless you are splitting the balanced coils so hum would occur. You may experience this effect when you use the 2 & 4 positions which combine the similar resistance coils in parallel, eliminating the hum. I could be wrong; let the debate ensue.

 

[nadzab]

...Humbuckers shouldn't need shielding unless you are splitting the balanced coils so hum would occur...

Correct.

 

[Wally]

I know that most Strat Pluses and Ultras with a 'swimming pool ' route area are shielded w/ conductive paint. So that helps.

Humbuckers shouldn't need shielding unless you are splitting the balanced coils so hum would occur. You may experience this effect when you use the 2 & 4 positions which combine the similar resistance coils in parallel, eliminating the hum. I could be wrong; let the debate ensue.

Okay, I'll bite. It has been said in a few different ways in this thread. I will try another..perhaps more direct...way. Shielding does not have any effect on the hum that is associated with single coil pickups...the hum that humbucker pickups eliminate. That AC hum that single coils generate will still exist after you shield a guitar that has single coil pickups in it. Shielding is a way to limit that antenna effect that Bro. T. Downs has explained to us.
Whatever one can do to shield the electronics will decrease the presence of extranneous noise that the(read: all) pickups will 'pick up' as antennae. Soem pups are worse than others, but they all benefit from shielding. Things such as Gibson's use of braided connection wiring from the pickups and between the pots and jack was a way to shield those electronics. Gibson used to encase their potentiometers in metal cans to further shiled ther electronics.
To the OP, if I were going to shield that guitar's cavities; I would shield the pickguard. Don't forget to shield the jack cavity, as well. Still-fiddlin's guitar has had some nice work done on it. Check out those pics well. All of that shielding is grounded. Good shielding job and a great wiring job. Very nice.