Shielding a Guitar

[ChrisK]

Here's a StewMac link;
www.stewmac.com/tradesecrets/promo/ts0052_shielding

Here's a link for copper tape where the self-adhesive backing is also conductive, so overlapped seams are electrically continuous.

[Teleblooz]

I've been unable to access the "Quieting the Beast..." pages on the old GN site (for quite some time). I can get to the homepage, but when I click on the link to those articles, I get redirected to Musician's Friend. What's up with that?

I used to have bookmarks with direct links to the pages, but compooters being what they are, they fell prey to Gremlins awhile back.

[sumgai]

TB,

Hear ya go!

"Quieting the Beast"



HTH




sumgai

[newey]

+1 to SG for something we probably should have done a long time ago!

Also, if your browser has tabbed browsing, you can access the G-Nuts pages despite the redirection to MF or other sites. The redirected page is a separate tab, on which you click the "close" box, leaving you at the page you wanted on the next tab down.

But the direct link from SG is neater, assuming one is starting from hereabouts.

[Teleblooz]

Why I'll be dipped.... It woiks!!

[gckelloch]

After researching shielding quite a bit, I conclude that it's not worth shielding PUP cavities with properly shielded PUP's, as leads shorting on the shielding, or increased hum from improper grounding can be issues. However, it may be useful in the control cavity. Either way, you'd only eliminate RFI.

You're unlikely to notice RFI noise over SC hum (EMI). Hi-Z PUP's are tuned far below the RF spectrum, so shouldn't pick up RF signals, but your control cavity wiring may inadvertently be tuned in the RF spectrum, so shielding it is a worthwhile endeavor.

Aluminum shielding has the added benefit of reducing buzz from bad light dimmers. It will also slightly reduce upper mids, if mounted under the pick guard around the PUP's in ~0.015-0.030" thickness. Such upper-mid reduction has a very nice sweetening effect, and was employed by Fender in the Pre -CBS years. I use it on my Wilde NF SC's in conjunction with special alloy strings for a more "soulful" tone. Still, shielding won't effectively reduce SC hum unless you use ~1/2" thick of Aluminum plating, and who's going to so that?

[sumgai]

Alright, I'm making book on who's gonna be the first to set straight the assertions made by gckelloch, above.

BTW, gck, I don't believe I've said it before, so....

to the NutzHouse! ;D


Stick around, I believe the discussion is gonna get lively, but it'll remain friendly, I assure you.






sumgai


EDIT: updated the "welcome" smilie - 2/7/20

[D2o]

Well ... I have shielded my pups (copper strip - not completely surrounded) and still found aluminum shielding of the cavity to be "worth it", as you say - and I've got bench testing to back it up.

Many others have shielded with the same results, even though they may not have recorded them.

And then there is you, Mr. Kelloch* ... if that is even your real name. This certainly begs the question of your so-called "research", Mr. Kelloch - have you actually bench-tested your hypothesis as some of us here have done? If so, let's see it!

Sincerely,
D2o

* I have no idea if your name is Kelloch ... it just seemed to add a little something to my lame attempt at sounding 1930's reverent. Oh, and welcome! Welcome to GN2!

[newey]

Either way, you'd only eliminate RFI.

If, by this statement, you mean that the hum from 60Hz mains current cannot be reduced through proper shielding of the cavities (both pickup and control cavities), I can only say that my anecdotal results indicate otherwise. And my results are backed up by D2o's testing, as he mentioned above.

On several guitars, and based on before/after comparisons with no other changes apart from the addition of shielding, the reduction in SC hum is fairly dramatic.

As for your objection to shielding on the grounds that leads could short or that improper grounding can cause hum, first off, leads potentially shorting is only an issue in the control cavity, since there generally aren't any exposed leads in the pickup cavity or cavities. And, in the control cavity, any such problem is easily solved by adding some electrical tape over the shielding in the areas where a lead might come into contact.

Improper grounding causing hum could equally be an issue in an unshielded guitar (granted, shielding does add to the number of those connections- by one). Proper soldering techniques, and double-checking one's work, should eliminate this as a concern.

[b4nj0]

Shielding does work, there's no question about it. "ye cannae change the lozaphysics" as Scotty said. If it were otherwise, then we would no longer need to use co-axial cable for guitar leads in an unbalanced configuration. A twisted pair would both suffice and make the bean counters smile.

My only concern regarding the use of screening, is that of the effect of stray capacitance on the output. Of course, we are only talking about a few picofarads, but capacitance does have an effect over longer guitar leads so I'm not going to ignore it as inconsequential even if it is slight.
All guitars are equiped with (at least) six antennae. They are (or should be) grounded, but some interference is always going to find a way through. It's an example of the law of diminishing returns.

I finished a "tribute" (copy!) of a Danny Gatton Tele last year complete with original Joe Bardens. I screened every cavity with self adhesive copper foil and I don't know whether it's the screening, the Bardens or a happy combination of the two, but it is as quiet as a church mouse, even if I hold the guitar right up next to a dimmer switch doing its thing.

Screening works for sure, how you implement it is the wild card.
Half inch aluminium plate? Jeez!

[gckelloch]

Apr 20, 2013 13:18:58 GMT -5 D2o said:

Well ... I have shielded my pups (copper strip - not completely surrounded) and still found aluminum shielding of the cavity to be "worth it", as you say - and I've got bench testing to back it up.

Many others have shielded with the same results, even though they may not have recorded them.

And then there is you, Mr. Kelloch* ... if that is even your real name. This certainly begs the question of your so-called "research", Mr. Kelloch - have you actually bench-tested your hypothesis as some of us here have done? If so, let's see it!

Sincerely,
D2o

* I have no idea if your name is Kelloch ... it just seemed to add a little something to my lame attempt at sounding 1930's reverent. Oh, and welcome! Welcome to GN2!

My research is secondary: from the testing, writing and correspondence of others. Some of what I said is a matter of opinion regarding which type of shielding is actually worth it. It's the individual's call on all that.

Al shielding of the thickness I mentioned does soften the upper mids. Try it, you might like it.

If a rheostat is properly constructed/wired/etc, it won't cause buzzing. Al shielding guards against buzz caused by faulty rheostats. I should have clarified that.

If you or anyone has evidence that thin shielding significantly reduces SC hum (without affecting PUP tone/output), I would truly like to see those results. It's possible that eddy currents created by conductive tape wrapped around a PUP might reduce 60Hz hum and/or it's upper harmonics, but the same loss in tonal spectrum might also occur, so you would not have gained anything. I don't know how you would bench test to show that. Maybe that's what is happening?

In any case, I just thought I'd offer up what I've learned as a possible aid in trouble shooting or time-saving. Take it, leave it, or test for yourself. As I said, it's just what I've concluded. In keeping with that statement and to make matters worse, I don't think ground loops can occur in guitar circuitry where there is just one power source. I can't prove it, but only state so from my understanding of how ground loops occur.

[JohnH]

Apr 20, 2013 2:54:06 GMT -5 gckelloch said:

After researching shielding quite a bit, I conclude that it's not worth shielding PUP cavities with properly shielded PUP's, as leads shorting on the shielding, or increased hum from improper grounding can be issues. However, it may be useful in the control cavity. Either way, you'd only eliminate RFI.

You're unlikely to notice RFI noise over SC hum (EMI). Hi-Z PUP's are tuned far below the RF spectrum, so shouldn't pick up RF signals, but your control cavity wiring may inadvertently be tuned in the RF spectrum, so shielding it is a worthwhile endeavor.

Aluminum shielding has the added benefit of reducing buzz from bad light dimmers. It will also slightly reduce upper mids, if mounted under the pick guard around the PUP's in ~0.015-0.030" thickness. Such upper-mid reduction has a very nice sweetening effect, and was employed by Fender in the Pre -CBS years. I use it on my Wilde NF SC's in conjunction with special alloy strings for a more "soulful" tone. Still, shielding won't effectively reduce SC hum unless you use ~1/2" thick of Aluminum plating, and who's going to so that?

Actually I agree!

If you have screened pups, theres no advantage in screening the pickup cavity (but see below)

Control cavity screening yes, agreed, and its helpful

SC hum, is not fundamentally much affected at its low frequency by screening. But the buzzy higher components are reduced, and that is the 'RF' part I assume.

the sweetening effect, could be.

Massive amounts of conductive metal may reduce low frequency hum - I could believe it in theory, but dont know.

J

[gckelloch]

Apr 20, 2013 16:40:48 GMT -5 JohnH said:

Apr 20, 2013 2:54:06 GMT -5 gckelloch said:

After researching shielding quite a bit, I conclude that it's not worth shielding PUP cavities with properly shielded PUP's, as leads shorting on the shielding, or increased hum from improper grounding can be issues. However, it may be useful in the control cavity. Either way, you'd only eliminate RFI.

You're unlikely to notice RFI noise over SC hum (EMI). Hi-Z PUP's are tuned far below the RF spectrum, so shouldn't pick up RF signals, but your control cavity wiring may inadvertently be tuned in the RF spectrum, so shielding it is a worthwhile endeavor.

Aluminum shielding has the added benefit of reducing buzz from bad light dimmers. It will also slightly reduce upper mids, if mounted under the pick guard around the PUP's in ~0.015-0.030" thickness. Such upper-mid reduction has a very nice sweetening effect, and was employed by Fender in the Pre -CBS years. I use it on my Wilde NF SC's in conjunction with special alloy strings for a more "soulful" tone. Still, shielding won't effectively reduce SC hum unless you use ~1/2" thick of Aluminum plating, and who's going to so that?

Actually I agree!

If you have screened pups, theres no advantage in screening the pickup cavity (but see below)

Control cavity screening yes, agreed, and its helpful

SC hum, is not fundamentally much affected at its low frequency by screening. But the buzzy higher components are reduced, and that is the 'RF' part I assume.

the sweetening effect, could be.

Massive amounts of conductive metal may reduce low frequency hum - I could believe it in theory, but dont know.

J

I don't think the harmonics of 60Hz hum constitute RFI. RFI is more like white noise. I believe both Copper and Aluminum shielding do guard against it.

You can experiment with the affects of AL by using a pie tin, as PUP maven Bill Lawrence suggests. As you bring it close to the surface or rear of the PUP, you'll notice some slight hum reduction, but also some tone loss.

The tone loss affect is different when Al is oriented under the pick guard for the subtle "softening effect", as opposed to above or below the PUP, or vertically aligned on the cavity walls. It has to do with how the eddy currents cancel the signal.

[D2o]

Hi gck,

You know, while I have tested the efficacy of shielding the pickup cavities and won't debate that, for all my shielding of SC pickups, I don't think I've ever objectively measured any results.

My gut says there is less hum and they are quiter and even more resistant to interference by, say, CFIs ... to the point that I always shield my SCs ... but I have no objective evidence to support my gut feeling.

I haven't been too active with wiring and the like over the last couple of years, but next time I have an opportunity I will try my darndest to remember to do some sort of objective testing.

One last point on shielding the SCs - I use copper strip, because I have it, not screen ... which is preferable but I don't have any.

Cheers,
D2o

[gckelloch]

Again according to research by Bill Lawrence, shielding PUP cavities with copper tape shouldn't alter the tone, but neither will it decrease 60Hz hum. Perhaps you have experienced high levels of RFI, and the shielding actually helps with that? Shielding PUP cavities with Al tape would slightly alter the tone. Not sure how. I'm no engineer. I don't know what CFI is.

[D2o]

Oops - I meant CFL (compact fluorescent lightbulbs). Sorry about that. They are horrible inventions for accompanying strat style guitars, so it could be something other than 60Hz hum is being reduced. As for altering the tone, I almost always find SCs a little too trebly - so it could be that tone was altered and I liked it. Entirely possible.

Cheers,
D2o

[candyflipper7]

Apr 20, 2013 2:54:06 GMT -5 gckelloch said:

After researching shielding quite a bit, I conclude that it's not worth shielding PUP cavities with properly shielded PUP's, as leads shorting on the shielding, or increased hum from improper grounding can be issues. However, it may be useful in the control cavity. Either way, you'd only eliminate RFI.

You're unlikely to notice RFI noise over SC hum (EMI). Hi-Z PUP's are tuned far below the RF spectrum, so shouldn't pick up RF signals, but your control cavity wiring may inadvertently be tuned in the RF spectrum, so shielding it is a worthwhile endeavor.

Aluminum shielding has the added benefit of reducing buzz from bad light dimmers. It will also slightly reduce upper mids, if mounted under the pick guard around the PUP's in ~0.015-0.030" thickness. Such upper-mid reduction has a very nice sweetening effect, and was employed by Fender in the Pre -CBS years. I use it on my Wilde NF SC's in conjunction with special alloy strings for a more "soulful" tone. Still, shielding won't effectively reduce SC hum unless you use ~1/2" thick of Aluminum plating, and who's going to so that?

I have to disagree.

[gckelloch]

Surely, you don't have to. ;D

Here's the BL article if you haven't seen it: www.billlawrence.com/Pages/Pickupology/External%20Interference.htm

It's very concise and may take several readings to grasp, as do most of his articles. More of which are here: www.billlawrence.com/Pages/All_About_Tone.htm/Pickupology.htm

[cynical1]

Bill Lawrence, or more properly Willi Lorenz Stich, is one of the few people I respect in this industry. He's forgotten more than I'll ever learn.

I feel impelled to offer a little hard earned knowledge I've picked up along the way. Most professional musicians, especially studio musicians, need an instrument that is as dead quiet as possible.

From my experience, a couple coats of shielding paint and a layer of copper shielding tape with conductive adhesive in the cavity does the trick. Shielding the pickup routings is only as effective as the depth of the pickup. Single coils raised half out of the cavity will gain less advantage.

Tone is such a subjective thing that you could argue the benefits of installing 1/4" plates of unobtanium all day and still never come to any agreement. But noise is still noise.

Happy Trails

Cynical One

[sumgai]

gc,

First, I would've lost the pool (the bet) - D2o was the first to pipe up. Sorry, D!


Next, I'd like to ask you to place a sheet of aluminum foil between your strings and your pickup, then play something - what does it sound like?

And finally, you do understand that Willi Stitch is neither an Engineer nor a Scientist, correct? A good example of that is right here:

Eddy currents alter sound and output of a pickup and play an important role in pickup design.

Eddy currents are induced in metals in the vicinity of an AC magnetic field, creating a secondary magnetic field which opposes the inducing magnetic field of the coil. The dimensions, conductivity and permeability of the metal, along with the frequency of the current in the coil, determine the magnitude and phase relation of the eddy currents. An internal short in a pickup coil forms a conductive loop which, also, becomes the source for internal eddy current interference.

There aren't too many factual errors in that statement, but one or two stand out, and need addressing...

Paramagnetic materials are indeed subject to electromagnetic fields (implying AC), but the order of strength needed to do that to a noticible effect is quite a bit above what a vibrating string can produce with a pickup's coil. Period.

A secondary thought to that is, how pure is the aluminum?   It turns out that a sheet of aluminum foil is usually around 99% pure, but the subtlety of that remaining 1% is what will skew results from one researcher to another. That's another "uncontrolled factor" in anyone's experimenting with this material, and which can lead to misleading results.

And just for a gasser, who says that eddy currents have to be opposite? They can indeed be shown to complement a field, and not hinder it.


Now, never let it be said that Mr. Lawrence isn't capable of finding and elucidating meaningful results, far from it. However, he doesn't always come at the conclusion from the proper direction.* Meaning, that in the end, when the soldering iron has cooled down for the day, what counts is only the final product - does it sound good? Or, from Willi's standpoint, does it sound good enough to make players want to buy it? Indeed, he's a wildly successful man in that respect, we'll all agree on that.

But to take him as a primary authority on all things (or anything) related to pickups just because of that success, that's not what I consider the best way to conduct one's cognitive processes.

HTH




sumgai

* Or if he is doing so, then somehow it's getting mangled in the translation, on its way to the webpage.

[gckelloch]

I know of no one alive who has the knowledge and clinical experience with PUP design of Mr. Stich. I'm am also aware of his history and numerous patents and have talked with him many times. While he doesn't posses degrees in the field, I believe his genius and decades of extensive research and application more than make up for that. He was also chief engineer at Gibson corp for over a decade. I do consider him a primary expert on the subject.

sungai, while it's a good point you make about how external induced eddy currents may affect the signal regarding material properties and orientation to the coil, you'll notice that the last sentence in the statement you quoted refers to internal eddy current coil shorts, which always produce some kind of cancellation. They result from "crazed" insulation from excess winding tension using PE wire. It's not an issue with poly based wire insulation, but wire and insulation stretching is. It can result in skewed A/C performance and increased capacitance. Not sure what the results of the A/C issue are on tone, but increased capacitance means limited high frequency resolution unless lowered external capacitance is employed.

I've strayed OT a good bit, and just want to restate that what I have offered is just from my own conclusions. If anyone finds they prefer shielding SC PUP's, than more power to them. I mainly thought it might be informative to know what types of shielding may alter tone. Also, as I have stated a few times, the placement of such materials in relation to the coil will produce different results. It's just something to be aware of. FI, an 0.003" thick piece of AL foil held over a pickup probably won't alter the tone significantly, but that also depends on the high end resolution you are trying to achieve. How it might affect the tone when mounted vertically on a PUP cavity wall is another question. I don't know. I never tried it. I do know that a ~1/32" AL pie tin held either over or under my neck mounted P90 did reduce the upper harmonics of 60Hz hum a bit, but also dulled the tone in a way I didn't like.

I am still convinced that a paper thin sheet of CU, AL or of any other known materials are not effective shielding against EMI, but some materials are effective against RFI, and AL is effective against faulty rheostats. Nothing ever stated anywhere has convinced me otherwise. I trust BL's research and statements, which have always proven true when tested, and since I haven't the capacity to test every conceivable scenario myself. I believe that arguing this matter without conclusive evidence one way or another is somewhat pointless and fruitless. Why not experiment for yourself?

P.S. I once used my digital A/I to measure the level of 60Hz hum of a few different PUP's under the same conditions. How the level of string vibration output configures in to determine S/N ratio is near impossible, especially considering how guitar resonances influence vibrational power at different frequencies.

[newey]

I am still convinced that a paper thin sheet of CU, AL or of any other known materials are not effective shielding against EMI, but some materials are effective against RFI, and AL is effective against faulty rheostats. Nothing ever stated anywhere has convinced me otherwise.

Well, since no one else has linked to it, here's D2o's take:
www.guitarnuts2.proboards.com/index.cgi?board=reference&action=display&thread=3375

With all due respect to Mr. Lawrence (and he does deserve a lot of respect), I have to disagree with some of what he says, starting right at the beginning. The first sentence of the BL article states:

"#1. The basic sixty cycle hum caused by single coil pickups."

It's basic, all right, but it is not caused by single coil pickups. The source of the noise is your household AC, which has a frequency of 60Hz (i.e., 60 cycles per second, the rate at which the AC mains current alternates). A magnetic pickup acts as a receiver, because of the length of wire in the coil.

Shielding works, at least partially, because the shield blocks* some of that radiation. Cyn1 is right, the higher your pickups are out of the guard, the less the effect will be. But, done properly, there should be some effect, and it's usually pretty dramatic.

Disproving the effect of shielding also requires disproving Mr. Faraday, who discovered the effect of shielding over 100 years ago. The theory is pretty solid . . .

Now, I can see how one may think that shielding is ineffective if one believes that the coils are creating the hum in this first place, as opposed to simply receiving, and transferring it onto the signal.

Wrapping metal foil of any type close to one's pickups can alter the shape of the magnetic field, and thus can affect tone, usually adversely. That much is certainly true. But with Strat-stylr guitars, there's enough space that the shielding isn't really right on top of the coils. I've never heard any loss of tone in any of the guitars I've shielded.

And, gckelloch, which you are certainly entitled to your opinion, it seems to me that the whole of your argument is based on BL's article. That is what's known as an "appeal to authority", and is one of the classic logical fallacies.


*I know, "blocks" is not technically correct, the noise current gets shunted to ground.

[D2o]

Kelloch, you are hereby accused of not acting in the spirit of a true Nut! ;D

Do some before and after experimenting : either you will prove your hypothesis and waste no more or your time shielding, or you disprove it and benefit from shielding.

Cheers,
D2o

[gckelloch]

Interesting that BL states that single coils cause the 60Hz hum. That could be a translation mistake, or he just used the phrase loosely. Technically it is incorrect, and by his own logic, should be corrected. He is well aware that it is electronic equipment like transformers in vicinity that create the hum. You'll notice it might be weaker or stronger depending on proximity to various equipment. Yet another reason it's difficult to get consistent results. Still, I'm pretty sure it takes very thick shielding of Al to actually reduce that hum by a significant factor. Rather than argue, it's simple enough to test out for yourself. Just try the pie tin test and see how much EMI reduction there is. You'll find that it's not much if anything at all, but some decrease in the upper harmonics. Just becasue you might hear some decrease at 60Hz (which you probably won't) it wouldn't mean it's a significant decrease. It might be >1dB. That's hardly significant in my book. I'd think ~6dB or more would qualify as significant, but that is of course debatable. Interesting to see how a thick sheet of Cu would fair. Probably no decrease at all, but I don't have a thick sheet of Cu or any Cu pots to check with.

I'm not claiming to be an engineer or scientist, and I am not the subject in question here. Sometimes we just trust the research of others. I have chosen to do so, just as we all trust that the floor we step on in the morning will not disintegrate, or the water we drink will not suddenly turn to poison. We don't know exactly why, but we trust nature to be consistent. BL's statements have proven consistent to me, so I trust him. Take it or leave it, but don't kill the messenger. My personal preference is to always use some type of humbucking pickup. Several designers (including BL) have single aperture models which do not suffer from the drawbacks of older stacked designs.

[Deleted]

well, personally far from being anywhere near to the participants' experimentation and theoretical background, i noticed that when i play with my shielded frankenstrat neck cheap SC distorted, generally and at certain orientations/directions of the guitar it is pretty silent, to the point it would make perfect sense not to replace it with an HS-3 or other noiseless. When i get close to the laptop, hell breaks loose and it is unbearable to hear the noise. In this condition, the bridge HS-3 plays dramatically quieter. I can 100% feel the effect of while playing noisy, to just close the laptops' monitor, and instantly hear the sound getting almost clear. Also what i witnessed yesterday, my cheap plastic digital caliper also gets crazy near the laptop, i was almost on the edge of ordering a new expensive steel one, till i noticed that the said cheap digital caliper works perfectly, closes perfectly and displays perfectly, when not close to the laptop.
So the laptop condition would make a perfect shielding benchmark IMO.

[gckelloch]

Just to be clear, the Dimarzio HS series are the old stack designs. They sound less brilliant than standard SC's. They are very good for distorted lead tones. If you do want to go for noiseless SC's, the Dimarzio Area series are the most SC-like. Wilde (Bill Lawrence) has the NF series. I have those. Zexcoil's are a new noiseless design model using individually tailored windings per string. Neither design compensates for signal loss by using more wire, and the orientation of the magnets/coils virtually eliminates the phase-cancellations of the older stacked designs. These new designs are so good, there really isn't a point in getting standard SC's, unless you want some sort of special custom design, and don't mind the hum. Ferro-Kings Liquid pickups are a very interesting concept.

[Deleted]

There is a special section about pups. Anyway, i am pulling the trigger for the seymour duncan livewire classic II single, next time. I am sort of sick of all those underpowered SC pups.

[gckelloch]

Sorry to go OT. I mainly wanted to point out that there are now affordable noiseless SC options that don't compromise tone.

I've uploaded some screen pics of a frequency analysis of my GFS neck p90 covered in front with: heavy duty Al foil, an Al pan, and no shielding at all. I held the guitar at the same rather noisy angle while touching the strings in all cases. The vertical scale at right on the analysis plugin is in 6dB increments. As you can see, there is no reduction at 60Hz in any example. There is some upper-harmonic reduction with the Al pan, and none other than at ~700Hz with the foil. However, that and the very slight change in the first two harmonics could be that I moved the guitar a little.

drive.google.com/folderview?id=0Bx0CnqsQz_uYblRTLTQwam5FS2s&usp=sharing

[newey]

Do you have any photos of the test rig? I'm curious as to how much of the area surrounding the coil was covered in the various examples, as well as seeing how the shielding was grounded.

[gckelloch]

I just ran direct into my A/I (Presonus Firebox) Hi-Z input and into Cuckos Reaper software. My studio monitors were on, but I damped the strings with a cloth. I think A/I boxes are calibrated ~6dB lower than guitar preamp inputs to allow for the headroom to guard against converter clipping. Even so, the highest hum levels would still be below -75db, which is really good for a single coil -- shielded or not.

As I said, I just held the shielding and covered the entire front of the PUP several inches past the edges in both cases. Any grounding would be through my body to the bridge. I'm mostly water, so it should be adequate.

I suppose completely surrounding the PUP might make a difference, but I doubt it would be much different with a thin sheet of foil. There is the ~3db drop at ~700Hz. That would be noticeable and could make a big difference in some settings depending on the gain level being used, so it certainly wouldn't hurt to do it. I'm curious to see the results others might get with the same test using different pickups.