Seth's or PG's? That is the question.

Re: Seth's or PG's? That is the question.

ArtieToo said:
I love it when a "problem" solves itself. (Just as much as I love finding a guitar that I forgot I had.) So, the Seth's will go into the Pelham Blue EPI LP, and the PG's will go into my Agile Blue Flame LP.

View attachment 79857

No problem. :D



I agree with the first sentence. Not so much on the second.



I agree they may alter the tone, but disagree that it's due to eddy currents. IMHO



Read that. Don't agree. :)

Let me explain my position. Clearly, there are people more educated and experienced than me who promote this "eddy current" thang in guitar pickups. Bill Lawrence was a big proponent of this phenomenon. The math, and the results of my own research, don't bear this out. Eddy currents came to be an issue in power transformers, where the eddy current flow was enough to heat up the transformer frame, making it less efficient. But those levels don't exist in a guitar pickup. The output voltage of a typical humbucker, strummed normally, is around 500 mv's. If driving a 500k pot, in parallel with a 1M amp input impedance, you have a load of around 333k. That results in a peak current flow of approximately 1.5 microamps. Remember, that's the actual current flow that we want. Micro-amps! Any eddy currents created by that current level would be unmeasurably minute. Fractions of a millionth of an amp. "Trace" levels. (But not even that much.) Like the amount of alcohol in 7-Up. The alcohol in 7-Up has no affect, but can be measured in a lab. Thus the "trace" designation. I tried to measure the eddy current in a pickup cover in a temperature and humidity controlled calibration lab, in a Faraday cage, using a high tech calibrated pico-ammeter. That's a lab grade ammeter that can measure down to a fraction of a picoamp. We could not measure anything. Zip. Nada. No matter how hard we tried.

So . . . I'm just not buying the whole eddy current phenomenon as it applies to pickup covers. IMHO. :)
I'm not arguing that they don't affect tone. I'm just saying it isn't due to eddy currents.

Artie
Click to expand...

Artie,

Quickly wrote online statements are inherently discussible and everyone is certainly free to disagree with mine. :-)

That said, here are a few words to clarify what I’ve said:

-Unlike many people, I think that the faintness of a guitar signal is precisely the reason why this signal can be affected by almost undetectable physical interactions;

-some experiments that I won't detail here led me to consider that Foucault currents are a plausible explanation, although I don't see them as the only parameter involved when it comes to pickup covers (and although I don't think that covers are the only part potentially involved in Foucault currents: baseplates might be evoked too)..

-I also remember varous readings like this one: https://alexkenis.wordpress.com/201...t-of-pickup-cover-material-on-tone-and-noise/

-That said, I'm basically open to any hypothesis and testimonial oppposed to this POV.

-Ultimately, my considerations about Foucault currents / Eddy currents were anecdotal side notes in this topic: the main goal of my answers was to try to share with you my own humble experience with Seth/PG's in Epi LP.


So, I'm glad to read that you've made your choice and I wish you to enjoy your blue guitars... with or without Eddy currents (LOL). :-)

Regards,

"freefrog"
 
Last edited:
Re: Seth's or PG's? That is the question.

freefrog said:
-Ultimately, my considerations about Foucault currents / Eddy currents were anecdotal side notes in this topic: the main goal of my answers was to try to share with you my own humble experience with Seth/PG's in Epi LP.
Click to expand...

Yeah, and I got that. :)

It's so hard to get tone-of-voice into text. I hope my tone came across as just casual bar-side conversation. :beerchug:

I'll let everyone know how the pup swaps go.
 
Re: Seth's or PG's? That is the question.

ArtieToo said:
So . . . I'm just not buying the whole eddy current phenomenon as it applies to pickup covers. IMHO. :)
I'm not arguing that they don't affect tone. I'm just saying it isn't due to eddy currents.
Click to expand...

Your reasoning is wrong. It makes no difference what the output of the pickup is.

Any conductor in the presence of a magnetic field produces eddy currents. Eddy currents produce their own magnetic field that opposes the field from the magnet.

The part you are ignoring is that pickups are AC current sources. Impedance increases with frequency. This is why you always lose high frequencies with various things when it comes to pickups. It doesn't take much.

Now if you agree that covers change the tone, explain, in detail, how that happens. And also what changes in tone are happening.

Now lots of people, Bill Lawrence included, know the answer. Also look at the patent by Ray Butts for the Filter'Tron pickup. See the H shaped cutout? That's to lessen eddy current loses. Also look up the parent by Harry DeArmond that shows slots cut in the pickup covers to prevent eddy current losses. These were the pickups in the Fender Coranado.

You can try this yourself. This also includes "shorted turns" of a conductor such as copper wrapped around the coil with both ends touching. Bill Lawrence even has some parents using that.

If you bother to set up a frequency plot of a pickup, as soon as you place a conductor over the pickup the resonant peak will lower and flatten. Due to eddy currents.

If you think it's for another reason please demonstrate it.


Sent from my iPhone using Tapatalk
 
Re: Seth's or PG's? That is the question.

The "other" reason is why we have adjustable screws on humbuckers. It's why people cut the bottom of the screws off, underneath the pup, to alter its tone. Any metal in the proximity of the magnetic field refocuses it, changing the tone. No rocket science here. There's still no evidence of it being eddy currents. Keep in mind, even in large power transformers, where eddy currents were significant, it didn't change the shape of the waveform on the secondary. It just heated the transformer, making it less efficient. I doubt that the microscopic eddy fields in a pickup would generate any measurable thermal shift.

On the other hand, I would love to see an article, or experiment, where someone was actually able to measure, and quantify, the actual affect of an eddy current altering the tone in a guitar pickup. I really wouldn't mind being proven wrong on this one. I find it to be an interesting topic. Just one that I have a hard time swallowing.
 
Re: Seth's or PG's? That is the question.

ArtieToo said:
The "other" reason is why we have adjustable screws on humbuckers. It's why people cut the bottom of the screws off, underneath the pup, to alter its tone. Any metal in the proximity of the magnetic field refocuses it, changing the tone. No rocket science here. There's still no evidence of it being eddy currents. Keep in mind, even in large power transformers, where eddy currents were significant, it didn't change the shape of the waveform on the secondary. It just heated the transformer, making it less efficient. I doubt that the microscopic eddy fields in a pickup would generate any measurable thermal shift.
Click to expand...

In my understanding, your conclusions about the magnetic field can be right... without denying eddy currents. :-)

On the other hand, I would love to see an article, or experiment, where someone was actually able to measure, and quantify, the actual affect of an eddy current altering the tone in a guitar pickup. I really wouldn't mind being proven wrong on this one. I find it to be an interesting topic. Just one that I have a hard time swallowing.
Click to expand...

Here are a few indirect indices that I've personally found favorable to the idea that Foucault currents are at work with covers:
-putting then pulling off covers on a pickup typically reduces then increases its inductance - unless the covers are made of plastic : LOL;
-materials supposed to favor eddy currents are IME systematically linked to more "intermodulation distortion" from guitar pickups.

As a side note, we could refer to the laminated core designed by another pickup maker to build his noise sensing coil: he has imagined it to prevent eddy currents losses and IME, his system works since it leaves the primary resonant peak virtually intact. Granted, a coil core is not a cover: I mention that just as an indice about Foucault currents being most probably involved in guitar pickups.

But as I said, I'm open to other explanations.

I wish you all a nice day.

FF
 
Re: Seth's or PG's? That is the question.

And here, gentle readers, is where Psycho-acoustics becomes important, as opposed to "pure" engineering and physics.

While all of the maths is nice (and not unimportant), one has to consider exactly how much this impacts a resonant peak, and what level. If it is within a just-noticeable-difference, then it will go unheard, or undistinguishable from the original version.

So yes - every little thing can impact the tone and volume of a signal. But humans can't perceive every little thing. Thus this remains - at the "experiential level" a matter of debate.

And the only way to reliably test these things is in a blind experiment - which we are not going to do. Besides - a guitar itself could impact the tone far more than there eddy current....creating a confound.

So you can add/delete covers - but you KNOW it will sound different, which is why you did it. Or you can compare in different guitars, which you should also highly expect to sound different.

Remember science class and that experimental methodology thing? It was important.
 
Last edited:
Re: Seth's or PG's? That is the question.

I think part of the problem stems from not being able to create eddy currents without altering the magnetic field in a large way. It would be kinda like testing to see if you could taste 1 ml of alcohol in a glass of water, but the only alcohol you had was in a beer. The hops would swamp the alcohol. Sorta, kinda.

But now, back to our originally scheduled program: Installing the Seth's, as we speak. :)
 
Re: Seth's or PG's? That is the question.

Perhaps if there were a significant difference between covered vs non-covered pickups, Seymour Duncan and other manufacturers would openly advise customers of such and recommend uncovered. I realize there is the aesthetic value of having those nice chrome/nickle covers on the majority of Gibson electrics, but feel that if the difference was to a larger degree, Gibson (and PRS for that matter) would not use them as standards. Of course, that is just my opinion.

With that said, I just recently installed an uncovered Lollar low wind Imperial in the neck of my Epi Dot, and a covered SD Seth Lover in the neck of my Epi LP Custom Pro, replacing Parsons Street Alnico 5 HB's. Both of these guitars have Parsons Street Alnico 2 HB's in the bridge. My goal was to see which was better and more suitable for each guitar. I primarily play blues and want a low gain, clear tone without getting muddy. I also installed a treble bleed circuit on the Epi LP neck volume pot (cts 500k).

I am quite pleased with both pickups and feel they work very well for each guitar. As a matter of fact, I have not been able to do my weekly guitar rotation between Tele, Strat, LP & Dot, since I installed the Seth Lover. I just can't stop playing the LP now.
 
Re: Seth's or PG's? That is the question.

I think Gibson is battling the idea of sound vs tradition. Covered vs uncovered (looks-wise) is a personal choice, but traditional Gibsons had covered pickups, so the traditional Gibson models always will, no matter if one sounds 'better' than the other. To me, covered vs uncovered- there is no 'better', just slightly different.
 
You must log in or register to reply here.

Similar threads

R
Help me find the right pair of humbuckers...
Replies
5
Views
538
elelpe
elelpe
Chris EmCee
Will anything dethrone the '78?
Replies
19
Views
1K
jeremy
jeremy
strat dude
To shield or not to shield, is that the question?
Replies
10
Views
452
GuitarStv
GuitarStv
Rex_Rocker
Rediscovering the Fluence KSE's (and Moderns)
Replies
6
Views
604
Rex_Rocker
Rex_Rocker
Mikelamury
Mesa Mark V is on the way!
Replies
10
Views
470
GuitarDoc
G
Back
Top