Shielding.. What do you think?

Rabs

Ok, so ive never really had this chat before since I haven't been on a forum with so many builders before.

As I was talking about on my Korina build thread. Before this build I never felt shielding was necessary. My reason being that in all my years of playing ive always played a Gibson and none of them are shielded and ive never ever had an issue with interference at all..  So my thinking was well is it even necessary....?  And indeed have never had issues with my own builds and interference...

I decided however that this latest build im doing wanted it (it whispered in my ear ) and so went with the copper tape route.

So this leads me to questions..  What do you guys think about shielding in general ? and what sort have you found the best (tape or paint or whatever)?

Roland

Shielding is essential for single coils and tapped humbuckers. I use copper tape because it conducts better than graphite paint, and I can solder an earthing wire to it. 

ICBM

All Gibsons are quite well shielded. (Or at least apart from some cheap models.) They have metal-cased pickups, shielded braided wiring, and in some cases metal cans around the pots and jack.

Shielding is necessary where there is exposed single-core wiring for any distance, or you will definitely get noise. Like Roland I much prefer copper tape, I find it far more effective than shielding paint and easier to make sure it's a complete shield - I solder across each joint (just one spot is enough) too.

Just don't overdo it on something like a Strat - too much shielding too close to the pickups dulls the tone, so don't shield the pickup covers. I did this once thinking I was doing a really thorough job, then had to take it out again when I realised why the tone was so muddy. It's ok to shield the cavity in the body.

Andyjr1515

I tend to agree it's single coils and split coils that are the main problem but I think it's also linked to how much gain you generally play with and also how much you want to gamble on the venues you play at.

 I had a Gibson P90 LP model that I also had no problems with.  Then went to one venue - and couldn't use it at all (there was a bank of fluorescent lights at the bar).  Then went to another and the same happened (that was something causing it from the room below the venue room).  Had to sell it in the end.

ICBM

Andyjr1515 said:

I tend to agree it's single coils and split coils that are the main problem but I think it's also linked to how much gain you generally play with and also how much you want to gamble on the venues you play at.

 I had a Gibson P90 LP model that I also had no problems with.  Then went to one venue - and couldn't use it at all (there was a bank of fluorescent lights at the bar).  Then went to another and the same happened (that was something causing it from the room below the venue room).  Had to sell it in the end.

That's most likely not a shielding problem but the usual single-coil magnetic interference pick-up. P90s are about the most prone to that of any pickup.

I've had that experience too which is why I would not normally use any guitar without at least one hum-cancelling setting - even if it's two RWRP single coils - as my only gigging guitar. I have done in the past, but that was in a band where I only used a clean sound so it was never a noticeable problem - but I've also been in at least one venue where even that would have been.

normula1

ICBM said:

 too much shielding too close to the pickups dulls the tone, so don't shield the pickup covers. 

I once had to partially do this on a Les Paul Special bridge P90 as for some weird reason the cover got statically charged every time I played it and crackled like crazy as a result. A small piece of the copper tape stuck to the underside of the cover attached to ground sorted it. The whole guitar is a a bit of a static magnet as the scratchplate crackled too until I gave it the same treatment.

lysander

The thing I don't really get with shielding is that 95% of the noise comes from the pickups themselves which shielding won't help at all.
Has anyone done some proper experiments of shielded vs non shielded single coil guitar in exactly the same conditions ?
I'm always under the impression that a lot of it is hearsay and psychological, but I'd be happy to be schooled if someone had some scientific info ?

lysander

Case in point : I have a Vigier Excalibur, a fairly high end guitar, with some lovely and very tidy conductive painting in all the cavities... and nothing to wire it to ground making it completely useless ( there's some wishful thinking attempt through contact with the pickguard but no way that ever worked for more than 5 min  ).
Yet the guitar has very little noise simply because all the pickup positions are noise cancelling. 

Roland

lysander said:

Has anyone done some proper experiments of shielded vs non shielded single coil guitar in exactly the same conditions ?

Yep. Unshielded, cavities shielded but not connected together, and fully shielded. It hums unless the job has been done properly. In some buildings, where the wiring is faulty or there are old fashioned fluorescent lights, you get hum even when the guitar is fully shielded.

FelineGuitars

I favour a nickel screening paint that seems way more effective than a lot of the carbon/graphite paints some of which don't seem very electrically conductive.

I originally found it as an aerosol - you can still get it at RS components.
However, I got a bigger 5L non-aerosol tin of it (as it would go a lot further as much of the 400ml tin was propellant) - cost me £700+ but we shared it between a few luthiers so the cost was shared)

I screen all my own builds - I think it makes a difference and it's very good on noisy strats and teles so we get to use it as a treatment during repair work as a requested extra.

GSPBASSES

lysander said:

Case in point : I have a Vigier Excalibur, a fairly high end guitar, with some lovely and very tidy conductive painting in all the cavities... and nothing to wire it to ground making it completely useless ( there's some wishful thinking attempt through contact with the pickguard but no way that ever worked for more than 5 min  ).
Yet the guitar has very little noise simply because all the pickup positions are noise cancelling. 

 Control cavities with conductive paint in them do not  necessarily need an earth  wire connected to it, as it is earth by the pots. I all ways use conductive paint on my builds, I use the same paint as Feline.

fftc

lysander said:

The thing I don't really get with shielding is that 95% of the noise comes from the pickups themselves which shielding won't help at all.
Has anyone done some proper experiments of shielded vs non shielded single coil guitar in exactly the same conditions ?
I'm always under the impression that a lot of it is hearsay and psychological, but I'd be happy to be schooled if someone had some scientific info ?

Check this video. The guy likes to talk a bit but shows a before and after on the same guitar and you can watch him do the shielding process in another vid if you want.

Danny1969

lysander said:

The thing I don't really get with shielding is that 95% of the noise comes from the pickups themselves which shielding won't help at all.
Has anyone done some proper experiments of shielded vs non shielded single coil guitar in exactly the same conditions ?
I'm always under the impression that a lot of it is hearsay and psychological, but I'd be happy to be schooled if someone had some scientific info ?

I did a Jazz bass the other day, shielding it properly made a very noticeable difference. I use alloy scavenged from the rear of laptop LCD panels, mainly because I get lots of it and it works very well 

4 inchs od unshielded wire between a Strat and a hotrod deluxe on the drive channel will produce noise that was easily measurable on a DB metre ..... because of this I had to modify one of my own designs 

FelineGuitars

GSPBASSES said:

lysander said:

Case in point : I have a Vigier Excalibur, a fairly high end guitar, with some lovely and very tidy conductive painting in all the cavities... and nothing to wire it to ground making it completely useless ( there's some wishful thinking attempt through contact with the pickguard but no way that ever worked for more than 5 min  ).
Yet the guitar has very little noise simply because all the pickup positions are noise cancelling. 

 Control cavities with conductive paint in them do not  necessarily need an earth  wire connected to it, as it is earth by the pots. I all ways use conductive paint on my builds, I use the same paint as Feline.

I screw an earthed wire to any cavities that I paint so they are all connected and to earth.
I have heard the difference because we get very noisy guitars in that leave with much lower noise once we have added shielding.

NelsonP

I have a parallel shielding thread going here. My issue is identical to that in the video posted above.

http://www.thefretboard.co.uk/discussion/99720/tele-deluxe-hum-fix#latest

lysander

To be clear, I do think proper shielding can make a difference in a guitar if the guitar has hum buckers or other noise free pickups - though I do think a lot of factory shielding especially with graphite paint which is indeed often barely conductive is a bit of a joke. My Vigier example was an instance of that ( and in this case the pots made no contact with the cavity ).

However for single coils / P90 I just don't get it - the coil itself is basically 1/4 mile of antenna ( and is in fact very similar in design to some amateur radio antennas ) and will pick up a ridiculous amount of interference, so I just don't see how shielding a few inches of wires is going to make a noticeable difference to a signal which is already irreparably noisy.

ICBM

lysander said:

To be clear, I do think proper shielding can make a difference in a guitar if the guitar has hum buckers or other noise free pickups - though I do think a lot of factory shielding especially with graphite paint which is indeed often barely conductive is a bit of a joke. My Vigier example was an instance of that ( and in this case the pots made no contact with the cavity ).

However for single coils / P90 I just don't get it - the coil itself is basically 1/4 mile of antenna ( and is in fact very similar in design to some amateur radio antennas ) and will pick up a ridiculous amount of interference, so I just don't see how shielding a few inches of wires is going to make a noticeable difference to a signal which is already irreparably noisy.

Because it does.

The two types of noise are actually different, and you can quite effectively stop the single-coil noise by using RWRP pickup pairs - which retains the single-coil tone - or if you really have to, by orienting the guitar at a precise (usually awkward!) angle to the stage. These things don't stop the type of noise that shielding does at all though - which is omnidirectional - so it's still worth shielding even a single-coil guitar.

On a Strat in particular, the unshielded wire from the jack to the volume pot is a major source of noise, and if you do nothing else, replacing this with shielded cable will make a difference - particularly if you often play with the guitar volume down a bit, since it comes after the volume pot and so the noise is always present at full volume (unless the pot is right off, which does ground it out). Shielding the control cavity and the wiring channel will also help even on a Strat without RWRP pickups.

Rabs

Thanks for the input everyone.. 

Kalimna

To slightly sidetrack this thread, how would you go about shielding a hollowbody-style guitar? Or is it the case that you would just live with the interference?

I ask this as I will be building another hollowbody or two, and I'd like to make them as unwanted-sound-proof as I can...

Cheers,

Adam

lysander

You could potentially use shielded wire everywhere or at least for the longer wires, just make sure you solder the shield to ground for each wire.

ICBM

Build a Gibson-style wiring loom from fully braided cable. Although there are still a few areas - switch, pot terminals, tone caps - that are not well shielded, they're relatively small and these guitars are not usually noisy.

If you want to do it really thoroughly you could use shielding cans on all these as Gibson did in the 1970s, but it's a lot of work and makes future maintenance - even simply cleaning the pots - difficult.