Pole piece screw position question

[Liarspoker]

Quick question.

I love the sound of the pick-ups on my Ibanez AFJ85 while the pick-ups on my Ibanez AS93 are more high gain.

While I know that the two pick-ups are different I also noticed that the pole piece screws were in different positions.

On the AFJ they are on the bottom towards the bridge of the pick-up while on the AS they are on the top towards the neck.

One of my students brought his Les Paul in last night and his high gain pick-ups also have the screws up at the neck side of the pick-up.

Does the screw position affect the sound? Is it just a coincidence that the higher gain pick-ups have the screws towards the next and the lower output pick-up has them lower?

Thank you

[Jimmy blue note]

Someone has reversed the position on the guitar in the first photo.
Yes, it does have some effect, but it's subtle. It gives individual volume adjustment and that adjustment will have more of a tweaking on higher frequencies when reversed.
This overall effect is less as you lower the pickup (inverse square law tends to average any tweaking the farther the pickup is from the string).

This was done more commonly on guitars that had a single pickup in an attempt to tweak higher frequencies when the pickups were set closer to the strings (more trebly an hotter).
It's one factour but only one, and personally, I don't hear much of a difference, but then again I don't keep my pickups very close to the strings.
Play around. It's fully reversible and you might find it does make that difference to you.

[sgosnell]

When Gibson started production of the humbucking pickup, the factory workers supposedly asked Lover which way the pickups should go. His opinion was that it didn't matter, but the factory decided to install them with the polepieces on the outside edges - near the neck on the neck pickup, near the bridge on the bridge pickup - and that's the way it has been done since. It was decided based on looks and standardization, nothing else. At least that's the lore. I wasn't around, so I can't say if that's the actual truth.

[Jimmy Mack]

I have reversed my pickups on hum bucker equipped guitars....but I also raised the polepieces when I did, to take advantage of the new positions of the p/ups.
On one guitar, I reversed the neck p/up to get a somewhat brighter tone, and on another, I reversed the bridge p/up to tame its brightness. This worked very well for me - it tamed the bright tone of the p/up but also allowed a more "airy" tone to that p/up.

I hope this helps

[rpjazzguitar]

If the pickup senses the string near the node (24th fret equivalent) it will sound a little mellower than if the pickup senses the string anywhere else. This, taken to an extreme, is why bridge pickups sound more trebly.

When you turn the pickup around (screws nearer the bridge), my guess is that it will sound about the same if the screws are flush with top. But, when you raise the screws, you're now sensing the string (more) off-node. That means the screws are sensing higher harmonics to a greater degree. It will sound less mellow.

I don't know if that's really audible. Maybe it's just something that can be measured but not heard (or maybe I've got this wrong).

Wes had a guitar with the screws near the bridge and nobody complained about his tone. I don't recall that the screws were raised though.

The L5S (solid body guitar with the L5 trim) had the neck pickup behind the node. Getting it under the node would have required taking that little pointy end off the neck. Some have proposed that the model never really caught on because the pickup position negatively affected the sound. OTOH, there might have been other reasons.

[JCat]

This is a most fascinating subject. Guitars do sound different, but mostly due to things we cannot see with a naked eye. Most folklore (e.g "Rosewood sounds dark, Maple sounds bright") stems from the fact that people are listening with their eyes. When comparing guitars, use your ears.

The PAF humbucker pickup

got two coils inside, but only one of them got adjustable pole screws. These coils may or may not be balanced (of equal wind).
These pickups are typically suspended in a plastic pickup ring and may or may not be parallel to the string plane. If not, the pickup is tilted, resulting in one of the coils being closer to the strings.
When flipping a tilted humbucker 180 degrees this is most likely going to affect the sound, especially if the coils are unbalanced.
The pole screws are there for the purpose of adjusting string-to-string output balance. This is not to be confused with the fact that a pickup can be set to slope (higher on the treble side to attenuate bass).
Humbucker pole screws get magnetized by one bar magnet inside, shared by both coils. The screw alloy plays a role in the equation (not to be confused with a bar magnet of A2 or A5 etc).

Pickup adjustment in theory

There's an interview with Seth Lover claiming that his original design didn't have any pole screws, but that it was a requirement from the marketing department. He was insinuating that pole screws is an unnecessary feature. He didn't come up with the idea himself.
Pole screw adjustment was no novelty, because prior to the humbucker, Gibson already got the P-90 single coil that had adjustable pole screws.
Fender single coils on the other hand never got adjustable pole slugs. A fact that makes some people argue that this is but an unnecessary feature. The Telecaster got flat slugs, but the Stratocaster got staggered slugs, (individual poles at different heights). So Fender certainly didn't ignore the question.
At that time all guitars came with a wound 3rd (thin magnetic core). These days most people use a plain 3rd (massive, solid magnetic string) that generates a much stronger pickup signal.
The high 3rd slug on a Strat is supposed to balance a weak wound G-string.

Pickup adjustment in practice

A pickup is located in a multidimensional grid:
i: Length of string, or node. Fixed, non-adjustable. The six poles may be situated at equal distance from the nut (e.g a Telecaster neck PU) or on different locations (e.g an angled Telecaster bridge PU).
ii: Height, distance to the strings. Adjustable.
iii: Slope (typically higher on Treble side). Adjustable. Arguably a sub-category of height.
iv: Tilt, meaning the pickup is leaning towards the nut or towards the bridge. The top of the pickup is not parallel to the string plane. Sometimes Adjustable (e.g a Telecaster bridge PU) sometimes not (e.g a Telecaster neck PU)
v: Staggered poles, (slugs or scews) meaning that some strings are closer to the receiver than others. Sometimes adjustable (e.g Gibson) , sometimes not (e.g Fender).

Optimal pickup adjustment depends on many things, not least the individual player and his playing technique and ears, string set, amp & speaker and style of music. And then of course the individual pickup and the individual guitar. Guitars are different and so are the people playing them.

Tip: Each time you adjust bridge height and neck relief (typically as a result of regular season climate variation) you are de facto also altering the pickup location relative to the strings, meaning pickup re-adjustment is part of a regular setup routine.

[Herbie]

I think that turning the neck humbucker screws nearer the bridge would help avoiding boominess, not necessarily adding much treble. Especially if You lower the pu and raise the screws. But I have not tested it.