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

11 Gauge

Doctor of Teleocity
Joined
Mar 21, 2003
Posts
12,810
Location
Near BWI Int'l
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.
Thanks for all the great details.

Now I know why Bill Lawrence went to the trouble to offer his Micro Coil design - he was intentionally reducing the area of the magnetic field around the poles.

I also now know that a guitar doesn't have to be comprehensively shielded to have some effect (against electrical field noise).

And that last paragraph really sums it all up well, especially WRT differing anecdotal experiences and comparisons. Now I know why I've been seeing all sorts of varying advice on what to do to get rid of 'noise'.
 

jim_pridx

Tele-Afflicted
Joined
Oct 1, 2008
Posts
1,882
Location
WI
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.

FWIW, I'm certainly not saying that the Ilitch system is "fool-proof" or a "cure-all" fix by any means, and while I can still detect noise to some degree under variable circumstances, the vast majority of the time I find that it's quite minimal and tolerable for my tastes.

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.

Rob, I'm in full agreement with everything you've said here with perhaps the exception of the idea that there's a "tone price to pay" when using dummy coils. My past experience has included testing the same guitar and pickups with the Ilitch system engaged while also bypassing the system, and I've found that the only tonal alteration or loss with it engaged might just be a tiny bit of high-end loss, but it's so miniscule that I barely notice it. It's certainly not enough for me to warrant dumping the system altogether.

BTW, I've also experimented numerous times with shielding all of the cavities with paint or copper tape, and while I've found that it helps to some degree in some venues, in the end I've also decided that it isn't worth the time and effort for the benefits it provides.
 

11 Gauge

Doctor of Teleocity
Joined
Mar 21, 2003
Posts
12,810
Location
Near BWI Int'l
Rob, I'm in full agreement with everything you've said here with perhaps the exception of the idea that there's a "tone price to pay" when using dummy coils. My past experience has included testing the same guitar and pickups with the Ilitch system engaged while also bypassing the system, and I've found that the only tonal alteration or loss with it engaged might just be a tiny bit of high-end loss, but it's so miniscule that I barely notice it. It's certainly not enough for me to warrant dumping the system altogether.
I think Rob is saying the 'tone price' only happens with high-Z dummy coils.

Since the Ilitch stuff is low-Z, it shouldn't appreciably alter the treble freq. response.
 

Antigua Tele

Friend of Leo's
Joined
Jun 2, 2014
Posts
3,258
Location
west coast
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.

RW/RP Strats are essentially a wholly unshielded humbucker, as well as RW/RP Jazzmasters and Mustangs, so that can serve as a point of comparison. I don't know if it's as quiet as a typical humbucker, but the significant drop in noise is easy to appreciate.

I'm not sure how much is helps to have just one size shielded, in the case of an uncovered humbucker, since electrical charges will interact in any direction. Given that fact, on a guitar like a Mustang, where the stock wiring allows for polarity switching, you should hear a big difference in noise as you switch between the starts and finishes of the coil, and the noise changes to some extent, but doesn't noticeably reduce, and not anywhere to the extent that humbucking reduces noise.

Something I'm not so sure about, but which makes sense in my mind, since shielding can't block low frequency magnetic waves, but can block electrical field noise, I would think devices in the area that are emitting noise, like a PC or a transformer, and are also shielded, are going to leak magnetic field noise while blocking their electrical field noise, and so in the guitar pickup you'd be more likely to get one and not the other.
 
Last edited:

jim_pridx

Tele-Afflicted
Joined
Oct 1, 2008
Posts
1,882
Location
WI
I think Rob is saying the 'tone price' only happens with high-Z dummy coils.

Since the Ilitch stuff is low-Z, it shouldn't appreciably alter the treble freq. response.

Ahhh......ok, gotcha! Thanks for clarifying this!
 

rigatele

Tele-Afflicted
Joined
Apr 20, 2014
Posts
1,673
Location
Canada
I'm not sure how much is helps to have just one size shielded, in the case of an uncovered humbucker, since electrical charges will interact in any direction.
The electrical model is a capacitive voltage divider, involving
1. the capacitance between the one-sided shield and the device
2. the capacitance between the device and any conductive objects nearby.

If the nearby objects convey changing electrostatic voltages, they function as the "plate" of a virtual capacitor composed of the objects, and the device.

If the device is placed very near to the shield, the virtual capacitor composed of itself and the shield, can easily be made orders of magnitude greater than the nearby object to device capacitance.

Under those conditions, the divider effect of the two capacitances reduces the interfering voltage from the nearby objects, by the same orders of magnitude, at the device.

Thus, even an incomplete shield can protect a device from electrostatic interference to a great degree. The maximum effectiveness is, of course, reached with a full enclosure.
 

TwoBear

Friend of Leo's
Joined
Mar 31, 2020
Posts
2,388
Location
oc. CA.
Proper shielding works exceedingly well for the gigging musician. It ain't just tape though. It's a faraday cage and a known thing unless you are one of the non science believers. If that's the case, well, I can't help you.

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.
I had a similar problem long ago in orange county California at a club opened by one or both of the Righteous Brothers. My stock three bolt Stratocaster was not liking it at all-I had to do as you did and stand still, and stepping on my gain pedals Was completely out of the question the noise would just go crazy. It turned out that the neon was on the same circuit.

They didn’t want to turn it off but they had to. They had an electrician come out the next day and move things around. It seems to be a pretty stock thing nowadays that most clubs and electricians know about-Most!

Another thing about Orange County was playing places like McCormick and Schmick‘s that were close to the John Wayne Airport-we stopped using wireless because airplane communication would come through really loud!
 

Telenator

Doctor of Teleocity
Vendor Member
Joined
Sep 19, 2005
Posts
14,716
Location
Vermont

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

Because shielding tape really doesn't work that well.
 

Southpaw Tele

Friend of Leo's
Joined
Jun 30, 2008
Posts
2,821
Age
49
Location
The Golden State
It's the difference between electro-static noise, which shielding helps enormously with, and electro-magnetic noise (60Hz hum and related), which shielding can barely touch. In my experience, I need both. They are two different solutions to two different noise sources.

A good example of electrostatic noise is the crackling and buzzing you get when you move your hands along the strings, or release them altogether. Shielding has helped me very well with this noise. But for the noise that JakeDog describes, which shows up in so many places (including my old house), only noiseless pickups fix that.
And even then, we can still have issues. I play at a church with a lot of lights and equipment that puts out EM interference; not to mention the Helix and in ear monitors I use. I shielded both my electric guitars (Tele and Jazzmaster) and put noiseless pickups in both and I still have issues. The weird one is where if I’m turned perpendicular to the direction my Helix is pointed in. The most common is when I have things set for lead work with a lot of overdrive. I also have to engage the noise gate on the Helix. Everything is grounded properly and we have ground lifts on everything. Just a lot of interference.
 

ndcaster

Doctor of Teleocity
Joined
Nov 14, 2013
Posts
11,430
Location
Indiana
in my next build maybe

 

chris m.

Doctor of Teleocity
Joined
Mar 25, 2003
Posts
10,421
Location
Santa Barbara, California
How do you define 'circuit noise'?
I think circuit noise is what a power conditioner filters out. Listen to signal without power conditioner. Turn on power conditioner. Whatever reduction in noise you hear is the result of cutting out circuit noise. Whatever remains is things like 60 Hz hum.
 

Si G X

Friend of Leo's
Joined
Dec 8, 2019
Posts
2,876
Location
England
How do you define 'circuit noise'?

I'd call it internal noise, but same thing .... shielding is to shield against external noise right? It's not a band aid for bad ground soldering or noisy pickups. ... it shouldn't be imo anyway although I know that what some seem to use it for.
 

Old Deaf Roadie

Friend of Leo's
Gold Supporter
Joined
Oct 11, 2017
Posts
4,530
Location
Goonieville, OR
In reply to @11 Gauge, I would say that this sums it up better than I could have in as few words:

I'd call it internal noise, but same thing .... shielding is to shield against external noise right? It's not a band aid for bad ground soldering or noisy pickups. ... it shouldn't be imo anyway although I know that what some seem to use it for.
 

Zepfan

Doctor of Teleocity
Silver Supporter
Joined
Nov 30, 2013
Posts
11,508
Location
Horn Lake, MS
Cooper tape and shielding paint is great for RF noise.

Aluminum tape does everything copper tape does while also being cheaper. If enough aluminum(quantity)is used, it can effect the magnet eddy currents of a single coil pickup and reduce or eliminate 60 cycle hum. This was written by Bill Lawrence as he found out by accident and did a write up about it.
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.

People hear the 60 cycle hum and it's high level of treble noise, once that's removed, they perceive a loss of treble. They aren't wrong, but the lost treble was in the noise that was eliminated. Had nothing to do with what the pickup offered. Same thing about microphonic pickups. Some don't think potted pickups sound the same as unpotted pickups and they aren't wrong either. Unpotted pickups turn all vibrations to signal and add a significant extra amount to the signal chain, take that away and we notice a difference.
 

hopdybob

Friend of Leo's
Joined
May 28, 2008
Posts
2,408
Location
netherlands
.


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.
could you explain how to do that?
 




New Posts

Top