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

dsutton24

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I've got a Mexican Strat that came to me with aluminum tape. Over copper tape. Over shielding paint. With Humbuckers. Hummed like crazy! None of this mess was bonded to ground, so naturally it was a noisy mess.

Details matter. Trying to patch things before fixing actual problems can be an enormous mistake.
 

willietheweirdo

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I don't need to gum up my guitar with shielding. The poly finish is already an impenetrable barrier. 😎✋⚡
 

nickmsmith

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It’s not an either-or thing.

Humbucker guitars also benefit from being shielded. I have some HB guitars that hum more than some of my single coil Teles.

And any single coil will hum if under the right amount of gain/compression.

Shielding is enough for most purposes. But humbuckers and noiseless SCs can certainly hum if they aren’t shielded well.

It’s like having seatbelts and airbags, for a somewhat, but not exactly identical scenario.

If you have seatbelts, it doesn’t mean you shouldn’t want/need airbags in your car, too. They both serve a similar goal. Or a hat and Gloves when in the cold weather, you get the idea. They aren’t mutually exclusive.

I wasn’t a believer in shielding until I needed it, tried it, and heard the difference. Teles are so easy to shield too. It’s not a silver bullet. But it is an improvement to interference.

60 cycle hum and outside interference are different things as well. Humbuckers stop the 60 cycle, shielding reduces the outside stuff.
 
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scooteraz

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I have a Strat partscaster (my first strat) that originally came with single coils and a well shielded cavity (foil everywhere in the cavity, all grounded and foil on the back of the pickguard with a connection to the body foil). It was never quite quiet enough for me, so I went to Lace Hot Gold pickups. Better, but they are not truly noisless. It now as EMGs, and is even quieter, but I’m not bonding in the way I though I would to the DG20 set with the EXP and SPG controls.

Then I listened to Chris Duarte on the Texas Sugar album, and noticed when he turned the amp from standby to play just before he started the song, there was distinct 60Hz hum, and then it disappeared in the music. I think there is some amount of “it goes away in the playing” for everyone. Certainly, where I play I’m not noticing the 60Hz so much, but then I am playing mostly in fairly recent buildings.

To answer the OP, Noisless pickups exist because shielding is not perfect.
 

bottlenecker

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Knowing how conservative a percentage of guitarists are, I'm actually not amazed.

Also, I think that possibly more and more folks are simply just playing at home these days, and a given percentage of them probably have semi-decent wiring, and no neon signs, or other such bar/club noisemakers.

We also probably need to remember that this is a sub-forum with Telecaster discussion as the parent, so possibly 20% or more forum members might not be playing much in the way of anything dirty or overdriven.

For the two groups above, noiseless pickups are probably seen as a solution to a nonexistent problem. And if someone is even moderately conservative regarding what they will put in a guitar, then they're probably actually trying to avoid noiseless. I think this group is possibly much more receptive to doing the shielding thing instead.

I've had plenty of issues with noise. I don't use humbuckers because I find the sound boring and dull for the vast majority of what I play. If the sound isn't exciting to me, why even play? Noise can be ignored, and I am not here to be everyone's cup of tea.

My solution to noise problems for many years was to just ignore it. Sometimes it's annoying, but it's a very reliable solution to just accept it, move on, and play. Considering most listeners have chosen their personal music related technology for convenience at the expense of sound, I think they can put up with some hum.

My current solution is to make the two pickups on my tele cancel hum when they're both on. If I'm in a really noisey venue, I can play everything from that middle position. That's noise cancelling without giving up anything for it.

It's funny you mention playing dirty or overdriven, because that's when I care the least about hum. Hum bothers me most when I'm trying to do real soft clean stuff with my fingers. When it's dirty, I'm more likely to be blasting, and couldn't care less about hum.

None of this should matter to anyone else, and I only typed all this to point out that everyone does different things, and does them in different ways. If this can be true in pragmatic endeavors with objectively measurable outcomes, certainly it should be expected in artistic pursuits with purely aesthetic results.
 

TheFuzzDog

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I'm not necessarily talking about not using humbuckers (meaning like Gibson PAFs). I'm talking about those (like yourself, and actually me, too) who prefer the sound of a single coil, but (if they are conservative) think that any technical variation of the original design, to reduce/eliminate the noise, somehow results in a sonic compromise from the original design. So something like a Strat pickup has got to be an actual single coil of wire on a fiber bobbin, with alnico polepieces.
Ah. I don’t have that concern. I’ve never used noiseless single coils because I just haven’t felt the need. If I did, I’d try them.
 

ndcaster

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I hated humbuckers until I tried DiMarzio's (misleadingly-named) "Humbucker from Hell" and Wilde's stacked bridge.

It seems to me that humbuckers became popular because, in addition to removing 60 cycle hum, they smacked the front end of the amp harder. For a couple decades, people loved the overdriven amp sound.

But now music is more varied, we have a lot more tools for getting overdriven and distorted sounds, and the average sonic expectation is more or less hi-fi.

Half my guitars are single coils, but I'm leaning ever more strongly in the direction of shielding and humbucking.
 

jim_pridx

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And I guess it's pretty much the same line of thinking for the Ilitch backplates and pickguards - seems like a lot of time and expense could be avoided.

The Ilitch system essentially enables your existing single-coil pickups to act as humbuckers by adding a dummy coil that's wired in conjunction with them. Suhr uses a similar system in many of their guitars as well. While it's not a "cure-all" fix, by any means, if you're hoping to use the pickups of your choice that aren't of the "noiseless" variety, it comes very close to eliminating nearly all of the 60-cycle hum. I've been using them for nearly 12 years now, and I'm totally sold on them. Whether you're playing quiet at home, loud at a gig, or recording through your home DAW, it just works! From my viewpoint, the only downside is that they're a bit on the pricey side.
 

Peegoo

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question for the EEs though - why humbuckers (mostly) don't hum but they buzz?

I am not an EE. Hum is usually 60hz (120Hz, mostly), from the ripple/sine wave in the AC mains power in the US, and 50/100Hz ripple in the UK, etc.

Buzz is generally caused by H-field electromagnetic interference (EMI), which is not in the radio frequency (RF) spectrum, but rather it's near-field magnetic flux transmitted mostly by electric motors, power transformers, and power supplies. More info here, from a paper I wrote years ago.

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Signal, Noise and Shielding

Playing in an electrically noisy environment is bad enough, but using high gain for feedback and effects just makes it worse because the signal chain cannot differentiate between signal (the desirable sound) and noise (the undesirable sound). Everything gets amplified. The earlier in the chain the noise enters, the worse the problem will be. Every gain stage amplifies the noise.

Shielding a guitar's cavities will block high-frequency RF/EMI. However, copper and aluminum (both known as good shielding materials) lose their ability to block low-frequency electromagnetic fields when the noise frequency approaches 1 kHz and below. This is why 50/60 Hz hum and its harmonics are often problematic in gain circuitry; the circuit amplifies the desirable signal along with the undesirable noise.

Below 1 kHz, high-permeability low carbon steel plate is used to block noise, but this is quite impractical for use in guitars and amps.

The problem of noise is compounded by proximity. In a playing situation where you as a player are situated close to noise sources, magnetic fields remain separate from the electromagnetic/RF noise component, and that makes eradicating the noise particularly more challenging. This is called near-field, or H-field magnetic flux. Farther away (far-field or E-field) the electromagnetic/RF and magnetic fields combine, and that makes managing noise a bit easier to do.

The bottom line is the best guitar shielding cannot block magnetic fields. Proper shielding will not completely cure the problem of noise getting into the signal chain because gain circuitry behaves like an antenna; it is super-sensitive to EMI and RF.

There are other steps besides shielding you should take and they involve moving the physical proximity of signal-carrying conductors (pickups, cables, pedals, amps, etc.) in relation to noise transmitters/sources. There are plenty of noise transmitters in a typical playing or recording environment. Some of the more common are

-Line noise in the AC supply
-Power supplies; wall warts/plug packs, power transformers, etc.
-Power cables/strips carrying alternating current or PCM-regulated direct current
-Lighting, especially fluorescent and LED types because they include power supplies
-Monitor displays, especially the old-school CRT types
-Electric motors, e.g., ceiling fans, refrigerators, computer fans, etc.
-Speakers; even shielded speakers can introduce noise into a signal chain
-Amplifiers; they contain their own power supply and transformer

As you can see, pretty much anything that uses AC or DC power can be a noise source. In addition to the things in your studio or music venue, there are external noise sources that offer more opportunities for frustration because you have little to no control over them.

-Airfields; radar signals and radio communications can be particularly problematic
-Commercial radio and television transmitters
-Ham radio transmitters in your area
-Electric power substations close by
-Atmospherics; electrical storms, solar activity

/////////
 

wildschwein

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Shielding tape's effects are most noticeable when you take your hands off the strings. This is where you will notice the difference between a shielded and a non-shielded guitar the most.

For what it's worth, Gibson went through a period, in the late '70s and early '80s, of shielding their guitars -- Les Pauls had shielding cans on the switch, output jack and the control cavity and no wire to the tailpiece/bridge.


09-cavity-shield-off-300x277.jpg



jack.JPG



PB070282b.jpg
 
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24 track

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single coils are antenea for being sensitive to electromagnetic interferences , shielding tape is not a remedy for that aspect , the shielding tape creates a feraday box if sealed properly ( an old principal used for isolating sensitive circuitry) that helps to deflect radio and electromagnetic sensitivity by blocking the interferences. humbuckers use a different principle similar to balanced line audio by combinimg the same signal 180 degrees out of phase then recombining the signal eleiminating and canceling out residual noise .

we live in a very noisy environment rife with electromagnetic and radio frequency bombardment,
I use Lace alumatone pickups in ine of my strats and alumatone buckers in another guitar , these are the quietest , cleanest sounding guitars I own , so much so I use one of the guitars for test purposes for diagnosing noisy amps , as all the garbage I hear is from the amp not the guitar
 

Rob DiStefano

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"Shieding" of ANY kind will affect tone, whether heard or not. Control cavity capacitance sucks tone as well. There are ways to mitigate the humbuzz within the build of true single coil passive pickups without resorting to dummy coils or biting the bullet and going full on dual coil. Passive dual coils wired in series or parallel will always attenuate treble to some degree. It takes a single coil to twang. It all is what it is. I've long ago learned to love the tone and disregard the buzz (if any). Lo-z transducers are a whole 'nother story and not my cup of tea either.
 

jim_pridx

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There are ways to mitigate the humbuzz within the build of true single coil passive pickups without resorting to dummy coils or biting the bullet and going full on dual coil.

Rob, what exactly are the "ways to mitigate the humbuzz within the build of a true single coil passive pickup?" I've certainly noticed that your pickups tend to be considerably quieter than other builder's pickups with similar specs (kudos to you for that!), but in 50+ years I have yet to install a non-noiseless single-coil pickup that didn't have a considerable amount of noise, especially in a hotter pickup and/or when one begins to overdrive it to some degree. With the Ilitch system, I have the ability to overdrive nearly any single-coil pickup with virtually no noise, all while maintaining the pickup's inherent tonal characteristics. And, of course, the twang is still there when the signal is cleaned up. I guess I just find it to be a very versatile tool without having to deal with the noise.
 

Antigua Tele

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Shielding only blocks electric field noise. Humbucking blocks magnetic field noise. That's why humbuckers have to be RW/RP, because they're cancelling magnetic fields, and why shielding has no bearing on that. It's the same difference as how capacitance is a stored electrical charge, and inductance is a stored magnetic field.

The reason humbucking is so much more effective than shielding is because magnetic noise is a lot more prevalent than electrical field noise, at least in this context.

Shielding can affect the tone by way of eddy currents or added capacitance, if the shielding is between the guitar strings and the pickup (like a cover) the string moving back and forth induces eddy currents in the cover, which creates a repelling magnetic field, and because eddy currents increase with frequency, it's treble that gets reprelled. That's why nickel silver covers are better than brass, less eddy currents.
 

Rob DiStefano

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I will NEVER use shielding of any kind - a waste of time that will typically obfuscate the inherent tone I build into each coil. There's enough capacitance happening already as the leads of a pickup make their way to the control cavity, and then the signal is passing through and around lotsa capacitance road blocks on the way to the jack, and then outboard to lotsa other "stuff".

As Bill Lawrence drummed repeatedly into my gray matter, it's the TOP of a passive coil that is its antenna for collecting the induced signal created by the excursions of magnetized steel strings, and thus is also a collector of floating humbuzz junk. I miss those conversations with Bill.

Think about all the passive bobbin COIL shapes used within single coil pickups. Are some of these shapes responsible for gathering more, or less, noise?
 

Rob DiStefano

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In terms of dummy coils, there is no question that the lo-z Illitch system is currently the absolute best way to greatly reduce humbuzz with the least effect on a single coil pickup's designed tone. In fact, there is typically zero effect on tone. Just killer for a Tele or Strat, but there must be a very close compatibility between the construction of the lo-z dummy coil, it's adjustable capacitors, and typically the single coil pickup(s) need to be properly built for the system - not really a big deal and the results are almost always stellar. I've worked a bunch with the Illitch lo-z system, great stuff. However, hi-z dummy coils are at best an easy band-aid against the buzz but there will be a tone price to pay. I no longer mess with hi-z dummy coils.
 

jvin248

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Noiseless pickups help ... but I've found the wiring between the volume pot and output jack can often be 50% of the idle noise collection in a guitar. Yet Fender continues to use two single wires (twisting does not help any in a guitar) in their premium models that collect noise while cheap '$100' Epiphones use shielded cable to the jack -- just like players use shielded cable from the guitar to the amp. See the Fender loaded pickguard image below for a randomly grabbed image. Some guitars contain that wire inside the Faraday cage, but Strats and Teles have a wood channel the wires run through and while it can be shielded, hardly any do it -- so they get noise. Fender continues this way because that's the way it was done in the 50s and some players complain -- even though they have wifi cell phones in their pockets and maybe an e-cigarette while running their laptop to record at the bar neon signs with LED lights over their shoulder.

If you are careful and patient, you can line the inside of pickup covers with foil leaving a tag to connect to the pickguard shield. Don't cut or short the bobbin wires.

In front of a recording computer, LP humbucker guitars without pickup covers collect a lot of noise vs covered humbuckers. I've tested both ways. If you want, you can make a little tinfoil hat for your pickup where you run a wire from that to the ground on the guitar cable or grounded bridge. Put on/remove the tinfoil hat and you can see if shielded pickups will help you.

Capacitance losses from pickup covers, machine-wound-high-capacitance pickup bobbins, and long guitar cables (which I've found the cheaper the cable the lower the capacitance per foot), can be greatly reduced by putting a series cap on the pickup hot lead. You can make those muddy cheap pickups sound like hand-wound-boutique pickups.

iu
 

rigatele

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You can have an Ilich system, and still experience sensitivity to the electrostatic component of any electromagnetic interference, if the guitar it's in has poor or no electrostatic (i.e. foil or metal) shielding in the control system. People would notice that more with humbuckers, except that humbucking wiring is almost universally shielded, even open coil HBs get some shielding from the grounded base plate. So it's not possible to differentiate or compare in that case because the HB have magnetic noise suppression.

Cavity shielding has NO effect on sound or tone, it can't. It's too far away from the place where the business of picking up is conducted, the area where the poles meet the strings.

Shielded wiring (aka coaxial cable) can affect the signal due to some extra capacitance, but the effect of capacitance from such sources is vastly overestimated by many people because they ignore the guitar cable capacitance which is much much greater. Not only does the greater influence swamp out the differences due to pickups and internal wiring, but it varies considerably from cable to cable, making it dubious that anyone could experience any significant difference from those.

It's sufficient, but not necessary, that the top of the coil is a noise receiver as Bill Lawrence indicated. Because it's definitely not the only source of noise. Usually, in a grounded system, magnetic noise is more prominent and that is why Bill focused on that aspect. That is why the Micro Coil exists, it specifically addresses that by reducing the area of the magnetic field around the poles, and thus the hum pickup (from the physics of coils - the wider the diameter, the greater the sensitivity to magnetic fields).

A lesser known subtlety of shielding is that it is not necessary for the shield to completely surround a device, to have some effect. That is why, for example, you can have a shielded pick guard and no cavity shield and still have some noise rejection. Even the fact that the ground wires in a completely unshielded guitar offer some protection, because they form a capactive voltage divider with the active wires and interference source, that reduces the level. It works because the guitar ground is earth grounded at the amp. But it's not as effective as cavity shielding.

Different environments present different and mostly independent levels of electrostatic and magnetic hum. This muddies anecdotal experiences and comparisons, especially when the difference between E and M interference is not known or understood.
 
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11 Gauge

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Shielding only blocks electric field noise. Humbucking blocks magnetic field noise. That's why humbuckers have to be RW/RP, because they're cancelling magnetic fields, and why shielding has no bearing on that. It's the same difference as how capacitance is a stored electrical charge, and inductance is a stored magnetic field.

The reason humbucking is so much more effective than shielding is because magnetic noise is a lot more prevalent than electrical field noise, at least in this context.
I think this fully answers my question, in a nice and simple way.

Magnetic field noise is indeed a lot more prevalent than electrical field noise (at least in this context, as noted), and shielding doesn't block magnetic field noise. It really is as simple as that. Hence all the pickup designs (and stuff like the Ilitch backplate and pickguard) that attempt to block the magnetic field noise.
 
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