2015 Gibson SG Pickup Upgrades?

[ThreeChordWonder]

Well, there's about 200 years of engineering and science...

And I was talking frequency not amplitude.

The amplitude of the vibration will be determined by how hard the string is plucked, and that, in turn, will determine how loud an acoustic string sounds, or how large the induced current in the pickup is. That's why an open e, properly tuned of course, always produces an open e, no matter how hard it's plucked.

The proximity of the string to the pickup determines how strong the magnetic field is, it diminishes with radius squared, and also, therefore how large the current induced in the coil is. But the stronger the magnetic field is, the greater the damping force experienced, and so the decay in the vibration will be affected accordingly.

 

[ThreeChordWonder]

https://youtu.be/cnH2ltfW48U

https://youtu.be/BSIw5SgUirg

In the second vid you can see how the amplitudes of the vibrations decrease as you go up the harmonics.

 

[beaubrummels]

The proximity of the string to the pickup determines how strong the magnetic field is, it diminishes with radius squared, and also, therefore how large the current induced in the coil is. But the stronger the magnetic field is, the greater the damping force experienced, and so the decay in the vibration will be affected accordingly.

Right, and it's the string disruption to the magnetic field that the pickup is sensing, which according to your post changes every radius squared (I'm assuming that's radius of the string travel when vibrating? or is it the thickness of the string itself?), either way, small adjustments in the distance from the pickup to the string produce perceptible change. The mode or frequency isn't mechanically what the pickup is sensing. It's mechanically picking up the amount of disturbance in the magnetic field. If that disturbance takes place at a frequency, then that frequency will be reproduced, but that's not what adjusting the pickup height affects.

 

[eclecticsynergy]

A difference in neck pickup placement can affect tone and feel noticeably.
There are players who prefer 22-fret PRSs over 24-fret ones because of the neck pickup placement.

Near the bridge it makes even more difference I think.
String excursion is less there, sure, but the critical treble frequencies are very prominent.

Forty years ago I moved the bridge humbucker on one of my Floydcasters a mere quarter inch further away from the bridge.
I did this on the advice of a friend, who later went on to be Steve Howe's touring guitar tech.

It transformed the guitar's voice far more than I'd expected; I remember being amazed at the change.
Warmer highs, richer mids, smoother overall and maybe just a smidge more output.

 

[ThreeChordWonder]

Radius from the center of the magnet(s) and therefore the center of the magnetic field. The magnetic field diminishes 1/radius squared, not linear, so small changes in the distance between string and magnet(s) create big changes in the induced current. Double the radius, the current induced in the pickup drops not to 1/2 but 1/(2 × 2) = 1/4.

And it's not mechanically picking up anything. There is no mechanical contact between a guitar string and a regular magnetic pickup. Piezo, yes. Regular pickup, no.

The movement of a conductor in a magnetic field induces a current in the conductor and vice versa. It's called electromagnetic jnduction.

As demonstrated by Michael Faraday at the Royal Institution in 1830 or 31, I forget which. He actually put on a public demonstration which he thought would prove there is not a link between electricity and magnetism, only to prove that in fact there is.

 

[ThreeChordWonder]

A difference in neck pickup placement can affect tone and feel noticeably.
There are players who prefer 22-fret PRSs over 24-fret ones because of the neck pickup placement.

Near the bridge it makes even more difference I think.
String excursion is less there, sure, but the critical treble frequencies are very prominent.

Forty years ago I moved the bridge humbucker on one of my Floydcasters a mere quarter inch further away from the bridge.
I did this on the advice of a friend, who later went on to be Steve Howe's touring guitar tech.

It transformed the guitar's voice far more than I'd expected; I remember being amazed at the change.
Warmer highs, richer mids, smoother overall and maybe just a smidge more output.

My 22 fret Fender Strats and Teles have the same scale length as a 21 fret Fender. The fretboard merely extends further back towards the bridge. You could extend a fretboard all the way to the bridge and it wouldn't change the way the string vibrates. The number of frets is therefore irrelevant. It's where the pickup is located relative to the points if macmximum and minimum vibration amplitudes that matters.

The bridge is a null point. That is to say, the string isn't, or shouldn't be, moving at the bridge. The amplitude or excursion fo the string is greatest in the middle and so moving the pickup further away from the bridge means the induced current will be higher. Indeed SD told me to match a 7.5k Jazz neck with a 17.5k TB4 bridge because in the neck the bigger string vibration amplitudes compensate for the fewer windings and resulting lower impedance.

 

[eclecticsynergy]

My 22 fret Fender Strats and Teles have the same scale length as a 21 fret Fender. The fretboard merely extends further back towards the bridge. You could extend a fretboard all the way to the bridge and it wouldn't change the way the string vibrates. The number of frets is therefore irrelevant. It's where the pickup is located relative to the points if macmximum and minimum vibration amplitudes that matters.

The bridge is a null point. That is to say, the string isn't, or shouldn't be, moving at the bridge. The amplitude or excursion fo the string is greatest in the middle and so moving the pickup further away from the bridge means the induced current will be higher. Indeed SD told me to match a 7.5k Jazz neck with a 17.5k TB4 bridge because in the neck the bigger string vibration amplitudes compensate for the fewer windings and resulting lower impedance.

I wasn't disputing anything you'd written and didn't intend for it to sound that way. My post concerned placement only.
The neck pickup on a 24-fret PRS is closer to the bridge than on the 22-fret models; that's why it sounds & behaves differently.
Similarly, the neck pickup on an SG is located closer to the bridge than the same pickup on a Les Paul.

Of course maximum excursion of the strings happens in the exact middle.
For an open string that's at the twelfth fret; when we fret notes it moves higher up the neck.
On a Strat or Tele, if you press down at the 12th fret, maximum excursion occurs directly over the neck pickup. This placement is not accidental.
24-fret superstrats all lose some sweetness in the neck tone since their neck pickup can't be located in that magic spot.

Naturally a pickup nearest the midpoint of active string senses more of the fundamental frequency and generates more output. My point was that because the amplitude decreases approaching the end - reaching zero at the saddle - pickup placement in the vicinity of the bridge matters even more than near the neck.

Moving a neck pickup changes its sound a bit, sure. But I can say from experience that moving a bridge pickup just a quarter inch altered its character significantly, as well as increasing the output. The change was not subtle; four decades later I still remember being happily surprised.

This has relevance to the choice of whether to mount your bridge P-rails conventionally or rotated 180 degrees.
Having the rail nearest the bridge would add some nice cut to the series tone, which by some reports can verge on muddiness.
It should also fatten the P90 tone, despite the P90 having a relatively wide magnetic field.
The downside would be a thinner and weaker tone from the rail by itself, a coil that isn't particularly strong even in normal orientation.

Only you can make the decision, of course. But IMO GuitarDoc's suggestion to rotate it is worth considering.
You could leave enough slack in the leads to rotate it again afterwards.
That way you'd be able to try it both ways, no further soldering needed.

 

[ThreeChordWonder]

^Agreed, but it seems like a lot of kerfuffle.

Wiring up the push pulls was bad enough to start...

 

[ThreeChordWonder]

I just got an $1800 income tax refund!!!

P-Rails arrive tomorrow

 

[GuitarDoc]

You obviously missed the point about the placement of the neck pup in a 24 fret vs 22 fret PRS, but eclecticsynergy clarified that in his last post. I agree will all he said, even that the rail coil will sound thinner and weaker when placed next to the bridge. To compensate for that I always put an A8 magnet next to the rail coil to bump up its tone and output. It really does work well and sound great. Try it. It's easy, quick, and cheap but the results will be worth it. And since the pup is new and has to be mounted anyway, might as well just rotate it (you can do it without changing the magnet, in which case it doesn't cost you ANYTHING in terms of effort, time, or cost, or you can change the mag before mounting which you would probably want to do eventually anyway).

 

[ThreeChordWonder]

^ I figured out what he meant after reading it again, thanks.

I have no idea what an A8 magnet is, but if needed I think it can be done later.

What I'm NOT going to do is start pulling pickups apart. I've tried it a couple of times with older / cheaper ones and it's never turned out well.

 

[ThreeChordWonder]

Done.

Pic here:

https://www.strat-talk.com/threads/hnpud.571935/