If shielding tape works so well, then why do noiseless pickup designs exist?

[hopdybob]

and we have ground lifts on everything.

isn't that a part of the problem?
i am no EE but when shielding has to be grounded to work, in my simple understanding ground lift would kill the function of shielding

 

[Southpaw Tele]

isn't that a part of the problem?
i am no EE but when shielding has to be grounded to work, in my simple understanding ground lift would kill the function of shielding

Sorry, I misspoke. We have the ability to ground lift if we have a ground loop anywhere in the chain. Thanks!

 

[11 Gauge]

I have achieved the no 60 cycle hum with single coil pickups in 10 guitar builds now using aluminum HVAC tape. I have stated it on several threads but many don't want to do it and many have tried and failed. You have to use thick tape and cover all the cavities and undersides of guards to get the desired result.

Why haven't I heard about guitar luthiers swearing by this? If it really works, then these luthiers wouldn't need to resort to noiseless pickups or the Ilitch pickguards or backplates.

I'd really think that this would be the answer with P90s, especially. And I bet I'm not alone in thinking that.

 

[Redleg37]

I’m waiting for a company to go all in on shielding and just put the electronics in a miniature faraday cage. I don’t think there isn’t reason why you couldn’t do it, especially with PCB based electrical components.

 

[Antigua Tele]

I’m waiting for a company to go all in on shielding and just put the electronics in a miniature faraday cage. I don’t think there isn’t reason why you couldn’t do it, especially with PCB based electrical components.

Shielding is adequate for most pickup because their circuits are have a low impedance, or they operate at high frequencies. Guitar pickups get the short stick because they're high impedance and operate at audio frequency. Magnetic fields pass through shielding, more effectively the lower the frequency of the wave, so the so the relatively extreme measure of "humbucking" is needed, although humbucking comes up in non guitar pickup applications sometimes. Ray Butts, who likely was the first to make a humbucker, had a radio engineering background so he was familiar with hum cancelling as a concept before hand.

 

[roeg]

But there are buildings we working musicians run across that even humbuckers are untenable.
I worked one place that I had to use a HB guitar and had to stand all night with my body rotated one direction (facing about 45 degrees to the right) only to avoid a loud buzzing sound.
I tried a line filter on night 2 and it did zero/nothing. Neither did a backup SS amp I brought.

Precisely. I played a place in Toronto(Cameron House) several times many years ago and had to do the same thing. I believe it was because a power transformer on a hydro pole outside of the club that was literally 15-20 feet away, albeit through a brick wall,lol. Very, very cool/indie club though. It was worth it,the clientele was just what you want. I played there with 2 different bands and always knew which way to turn for great sound, lol .I was using a humbucker equipped LesPaul. No humbucker could defeat that nuisance!

 

[rigatele]

Maybe the real reason some bands played with their backs to the audience?

 

[tfarny]

Noiseless pickups are trying to reduce/eliminate the inherent hum from a traditional single coil pickup, shielding is trying to shield the guitars electronics from external noise.

They aren't trying to achieve the same thing.

The inherent hum from a traditional single coil IS external noise....they are the same thing, RF interference.

 

[Si G X]

The inherent hum from a traditional single coil IS external noise....they are the same thing, RF interference.

Ah ok... thanks for that. That explains why my single coils don't really hum either.

 

[tfarny]

Ah ok... thanks for that. That explains why my single coils don't really hum either.

Single coils don't hum by themselves, they pick up 60 cycle hum from the air. That is why the amount of noise you hear when playing a single coil pickup varies depending on your location - more hum near neon signs, etc. If you were to play your strat way up in the mountains or on a sailboat, somewhere away from electrical noise you might not hear much hum at all.

Humbuckers & "noiseless" pickups use phase reversal to "cancel" that hum in relation to the musical signal, while shielding prevents the 60 cycle hum from ever reaching the pickups. Different solutions to the same problem.

 

[Si G X]

Single coils don't hum by themselves, they pick up 60 cycle hum from the air. That is why the amount of noise you hear when playing a single coil pickup varies depending on your location - more hum near neon signs, etc. If you were to play your strat way up in the mountains or on a sailboat, somewhere away from electrical noise you might not hear much hum at all.

Humbuckers & "noiseless" pickups use phase reversal to "cancel" that hum in relation to the musical signal, while shielding prevents the 60 cycle hum from ever reaching the pickups. Different solutions to the same problem.

That's really interesting thank you, I've heard so many people talking as if all single coils 'produce' 60 cycle hum I guess I've always thought that was the case.

never too old to learn something new I guess.

I've been lucky and never really experienced anything that's bad enough to worry about... which might just be because I've always played in loud rock bands where a bit of noise isn't really an issue... but at home and in our practice space it's pretty quiet too thankfully.

 

[Antigua Tele]

Humbuckers & "noiseless" pickups use phase reversal to "cancel" that hum in relation to the musical signal, while shielding prevents the 60 cycle hum from ever reaching the pickups. Different solutions to the same problem.

That's not quite right. They're different problems, one is a capacitive noise, electric field, the other is inductive, magnetic field. Shielding blocks the capacitive noise, because it gives captative noise sources a "route to ground" that is not the hot side of the circuit, but magnetic waves go through it like nothing. Humbucking addresses magnetic waves through cancellation, because there's no way to actually block them out. That's why Tele neck pickups are still pretty noisy even with a shield.

In either case, noise would be much less of an issue if pickups were low impedance, but the high impedance of pickups makes them behave a lot like an antenna, where you deliberately have an open circuit that is intended to pickup electromagnet waves from far away places. Even though a pickup is not "open" like an antenna, it has a high amount of resistance across is, which results in a similar outcome.

 

[tfarny]

That's not quite right. They're different problems, one is a capacitive noise, electric field, the other is inductive, magnetic field. Shielding blocks the capacitive noise, because it gives captative noise sources a "route to ground" that is not the hot side of the circuit, but magnetic waves go through it like nothing. Humbucking addresses magnetic waves through cancellation, because there's no way to actually block them out. That's why Tele neck pickups are still pretty noisy even with a shield.

In either case, noise would be much less of an issue if pickups were low impedance, but the high impedance of pickups makes them behave a lot like an antenna, where you deliberately have an open circuit that is intended to pickup electromagnet waves from far away places. Even though a pickup is not "open" like an antenna, it has a high amount of resistance across is, which results in a similar outcome.

Thanks for that, although I have to admit I only dimly understand it!

 

[Zepfan]

Why haven't I heard about guitar luthiers swearing by this? If it really works, then these luthiers wouldn't need to resort to noiseless pickups or the Ilitch pickguards or backplates.

I'd really think that this would be the answer with P90s, especially. And I bet I'm not alone in thinking that.

My guess is: 1. Most tried, but didn't use enough shielding or do it properly.
2. Many don't believe it'll work and don't bother trying.
I found this by accident and Bill Lawrence did too.

 

[Antigua Tele]

My guess is: 1. Most tried, but didn't use enough shielding or do it properly.
2. Many don't believe it'll work and don't bother trying.
I found this by accident and Bill Lawrence did too.

The reality is that in order for shielding to block low frequency magnetic waves, it would have to be several inches thick, and at the same time it would block out the magnetic change of the guitar string as well as noise, thereby defeating the purpose. The mechanism by which extremely thick shielding would block magnetic waves is the same as eddy currents, which with the thin shielding, still cause attenuation of treble with shield covered pickups, which is why players like Eric Clapton had removed the shielding cover from the PAF humbucker back in the day. 60 HZ is considered a rather low frequency in the audio spectrum, by the time you had a thick enough cover to block 60 HZ, you will have blocked all of the mids and treble coming from the guitar strings.

 

[Grateful Ape]

Speaking of Illitch...is he still in business? His website appears to be rerouting to some dodgy looking one...

 

[wildschwein]

I’m waiting for a company to go all in on shielding and just put the electronics in a miniature faraday cage. I don’t think there isn’t reason why you couldn’t do it, especially with PCB based electrical components.

It wasn't minature but Gibson did it in the '70s with Les Pauls. All the components were in metal cases and they didn't run a ground wire to the bridge with those.

 

[Zepfan]

The reality is that in order for shielding to block low frequency magnetic waves, it would have to be several inches thick, and at the same time it would block out the magnetic change of the guitar string as well as noise, thereby defeating the purpose. The mechanism by which extremely thick shielding would block magnetic waves is the same as eddy currents, which with the thin shielding, still cause attenuation of treble with shield covered pickups, which is why players like Eric Clapton had removed the shielding cover from the PAF humbucker back in the day. 60 HZ is considered a rather low frequency in the audio spectrum, by the time you had a thick enough cover to block 60 HZ, you will have blocked all of the mids and treble coming from the guitar strings.

Well i stumbled onto this using that aluminum skillet in my Strat-O-Rez build that you hated on.LOL It's 4mm thick and 8 to 9 inches diameter.
The HVAC tape is thick(not like aluminum foil) and if a lot is used it does the job.
Bill Lawrence achieved noiseless operation with a Telecaster aluminum bridge plate.

 

[Zepfan]

Why haven't I heard about guitar luthiers swearing by this? If it really works, then these luthiers wouldn't need to resort to noiseless pickups or the Ilitch pickguards or backplates.

I'd really think that this would be the answer with P90s, especially. And I bet I'm not alone in thinking that.

Several of the builds I've done have P90's. Also Telecaster pickups, Strat pickups and others.