Lowest magnetic pull with a reasonably efficient pickup

[Fluoroscope 5000]

If you ever used AlNiCo V Strat pickups with any gauge strings, you'll know how important magnetic pull becomes.

[Mike Sulzer]

The effect can be much more severe than damping, resulting in the replacement of the normal vibration of the string with apparently two close spaced frequencies and a rough transfer of energy between the horizontal and vertical modes. (Examine the vibration with a strobe.) It does happen on wound strings too, but certainly less so.

You know, the degree of magnetic pull really only becomes an issue if the mass of the string is low enough, and the polepiece close enough, that the polepiece can damp string vibration.

Nobody really concerns themselves with magnetic pull when it comes to basses, or wound guitar strings for that matter.

Now, if you're Billy Gibbons, and using those ultra thin strings on a short scale guitar, magntic pull may well be an issue of concern for your unwounds.

[fieldwrangler]

Considering that Steel can easily be saturated by Nd magnets, I’d think you'd need very small Nd magnets indeed. Maybe 2~4mm thick depending on the type? C5 or C8 might just be easier, and make sure to ground the poles/core directly to the chassis. Efficiency is hard to manage without knowing exactly how everything interacts and how the field is configured, but increasing inductance with Steel is more efficient than with more winds. You want all the winds to be as close to the core and strings as possible. A small, square cross-section coil close the core and strings will be the most efficient. Hand-winding invariably produces excess internal distributed C and possibly eddy-current shorts. I think 43AWG poly wound very slowly is the best bet, doing whatever you can to make the cross-section square, so all the wire is closer to the strings and core combined. For good articulation above 4kHz, you should probably aim for 3.5~5H for 500k pots, or 2~3H for 250k pots. A higher H value will require a lower C cable to get a sweet articulate high end. The magnetic aperture can be fine-tuned via screw height. I see no reason not to use screws in each coil. A Steel base-plate would probably be counter productive in a standard HB design, drawing the field through the coils and what not. Use “German Silver”, or use Brass for a different quality. Bill Lawrence sated that a thin brass Tele base-plate warms the sound in some way. I really like the crisp warm sound of my bass-plate GFS bridge D180 in my semi-hollow, but I don't think they generally sound good in hard sounding solid body guitars. Certain types of 4xx series Stainless Steel as the core and screws can work for less bass emphasis and a more focused resonance peak. Not sure where you'd get the core material. Screw inserts or nuts?? FI, you might want that in the neck, and Steel in the bridge...or use mini-HB bobbins in the neck for less upper-harmonic roll off.

There's a lot of very valuable info here, or maybe I just THINK it's valuable because almost all of it agrees with my own observations. A few minor details that I'll throw out for discussion:

"The magnetic aperture can be fine-tuned via screw height" -

This business of a magnetic aperture has often seemed to me to obscure pickup function more than it enlightens. I don't think that 'buckers really have a "wide aperture" - instead they seem to respond to string behavior at two points positioned above the two poles of the magnetic circuit. They are indeed intrinsically efficient. I like your emphasis on getting the winds close to both the strings & core; excessive screw pole protrusion tends to work against this. However, it can definitely affect tone & response in ways that can be appealing for some applications.

"Bill Lawrence stated that a thin brass Tele base-plate warms the sound in some way" -

I think this may actually refer to the brass covers on the neck units, perhaps others know the facts on this one.

Bob Palmieri

[JD0x0]

Wow! Lots of great info, here already. Thank you all for the contributions!

Why?

What exactly are you trying to accomplish by doing that?

I was hoping the narrow magnetic window would less affect the string compared to a wider one. The coil wind would be to compensate for the likely lower output of having a narrow magnetic window.


Not really into the piezo's sound with electric, unfortunately, but there's a wealth of info here, already, that is a huge help.

The reason for low pull, is what was described already. I essentially want to avoid all symptoms and any chance of 'stratitis' with the least string damping reasonably possible, from the pickup for maximum sustain and best intonation/pitch accuracy potential. Not to imply that my current pickups have huge issues with this, I'd like to have a pickup that has even less damping than what I'm currently working with. (Alnico 2/3 singles and Wilde L-90's)
I've come to enjoy the lower pull pickups, seems to get along with my playing style. I use a very wide dynamic range, when picking, and there are often times where I'll pick the strings extremely lightly. Having minimal magnetic pull definitely seems to help keep those notes going, without cutting out, and without gobbing on layers of compression. Also less damping seems to increase 'note bloom' which I like.

I have a lot of reading to do now

[Fluoroscope 5000]

Yeah, it can be more like two separate portions of string depending on how the field from each core is focused, but the screw heights definitely alter the note timbre. Brass covers also affect the tone. Here's the BL article in question:
Fender Telecaster® Electric Guitar Central -- No. 1 in the World

From what I've been told, not all AlNiCo II is the same. BL and DiMarzio mentioned a stronger grade with a quality more like AlNiCu III. Not sure what that is, but I'd look into it. I have a few HB”s and a mini-HB with AlNiCo V bars. I don't have any noticeable stratitus, and I set my pickups pretty close to the strings. The L90 has a V bar. I imagine it's longer than usual as well, so more powerful. It might be interesting to seek out this newer AlNiCo II grade if it's not already the new standard.

[big_teee]

FYI, Alnico 2 is stronger than Alnico 3.
Alnico 3 is the weakest of all the Alnico pickup magnets.
On stratitus, pickups that are configured RWRP helps cancel that out and was discussed by Seymour Duncan in his Q & A.
Brass baseplates and brass covers are known to rob highs, and give more of a duller sound.
Hardly anyone uses brass parts in pickups anymore.
However, you can use brass with Ceramic magnets to get a rounder sound.
T

[Fluoroscope 5000]

Yes, but if this newer grade of II were to FI interact more with the string field, and if that's also true of III, it would produce more similar results to III, which I'd think would be more upper-harmonics and greater sensitivity without the instability of III or excess pull of V. That's why I say look into it. That's all I have to say about that.

I'm curious how RWRP could actually affect stratitus if both magnets are pulling on the string and so far from each other. Something else worth looking into as well.

I've mentioned I'm not a builder. If my suggestions and insights are unwelcome, I don't need to be told twice. I only continue replying because I was told I could stay active if I "play nice". I hope I have done so thus far.

[big_teee]

You're fine.
I was just mentioning some things I've read and observed as well.
I'm not aware of different types of A2, except that some sound brighter than others IME.
T

[big_teee]

I found the Q & A by SD.
it is Q&A 323.
301-325 - Seymour Duncan

323. What is "Strat-ites"?
Often caused when the height of the pickup is adjusted close to the strings and dissonant overtones are heard as you play further up the frets. It is really noticeable as you play on the bass strings way up the fingerboard. The overtones are due to each pickup having the same polarity (3 South or 3 North Polarity). The string acts like a keeper but is magnetized in three locations. As the magnetic field from the center pickup travels down the string, the magnetic field is repelled by the two outside pickups. As the like poles repel each other down the string, the overtones become very distorted sound wise. The Strat-ites can be reduced by lowering the pickups on the bass side of the pickups. Also reversing the magnetic polarity in the center pickup will help reduce magnetic repulsion in the string. The notes will have a clearer sound as you play up the frets. The string can have several magnetic fields that react with the pickups magnetic field.

We all have our heroes, and Seymour Duncan is one of mine.
There is some great stuff in the SD Q & A.
Enjoy!
Seymour's Q & A - Seymour Duncan

[Fluoroscope 5000]

That's creative reasoning, but I don't think the fields are strong enough in the string so far from the pole to have any affect on the string harmonics. It would also be pulling from each side on axis with string. Counteracting the string tension would then be that much harder, init? Consider how strong the field is right above the pole compared to how strong it would be ~1” or more down the string. I think it's just that the magnet causes the string to vibrate asymmetrically, pulling the harmonics above the string out of whack. If strong enough, the note pitch will even go sharper as you play up the neck and the string gets close to the neck pickup. It depends on the pole stagger, but my experience is that the low E and plain G are affected most, having more mass at nearly the same tension as the other strings. I don't have a RWRP set of AlNiCo V pickups. I really couldn't get the note timbre I want with the set I have without noticeable inharmonious...ness. It's not horrendous, but I have no intention of keeping the pickups anyway.

You could test the SD idea pretty easily if you haven't already.
1. Lower the bridge and middle pickup way down.
2. With only the neck pickup on, raise the neck pickup until you clearly hear modulations fretted above the 12th fret.
3. Raise the RWRP middle pickup to see if it reduces the modulations. My guess is it will only add to them. I'm curious to know, but would need to hear recordings each way to be convinced.

[big_teee]

I've never done the experiment, but never had any issue with the problem.
I guess I don't adjust them that high.
Note 311 also talks about it.
I'll try to do the experiment.

311. How do I get rid of that dissonant overtone in my Strat pickups when playing notes on the lower strings at the higher frets?
Lowering the neck and middle pickup on the bass side of the strings helps reduce the “Strat-ites”. I remember needing a pickup for the center position of an old Strat and I ended up putting an old Duo-Sonic pickup that was reverse wound and reverse polarity (RW/RP) from the existing bridge and neck pickups. I found that when I put the lever switch in the two and four position of a normal 3 or 5 way lever switch the two positions became quieter and I noticed that the dissonant overtones on the lower strings was reduced. I used a Boy Scout compass and noticed that each pole piece on the pickup magnetized the string with the same polarity and would repel as I moved the compass in between the neck and middle pickup and the middle and bridge pickup. Than I remembered in science class that like magnetic fields repel and opposite magnet fields attract. The strings had several areas where the string was trying to repel the magnetic field within it. This would cause the string to have an inaudible overtone that got worse as you moved up the fingerboard.

[Antigua]

I found the Q & A by SD.
it is Q&A 323.
301-325 - Seymour Duncan

The overtones are due to each pickup having the same polarity (3 South or 3 North Polarity). The string acts like a keeper but is magnetized in three locations. As the magnetic field from the center pickup travels down the string, the magnetic field is repelled by the two outside pickups. As the like poles repel each other down the string, the overtones become very distorted sound wise. The Strat-ites can be reduced by lowering the pickups on the bass side of the pickups. Also reversing the magnetic polarity in the center pickup will help reduce magnetic repulsion in the string.

Very, very unlikely. The magnetism travels up the string, but it loses strength within a very short distance. If you introduce another magnet a couple inches away, it's going to completely overpower whatever induced magnetism remains from the first magnet. Fluoroscope 5000 is almost certainly correct, the additional magnetism, though opposite polarity, would serve to further pull the string further downwards.

top of magnet


close


further


furthest

[big_teee]

You're in the wrong place.
why aren't you checking where the neck and middle pickups are.
I don't think you proved anything.
Have Fun,
T

[Antigua]

You're in the wrong place.
why aren't you checking where the neck and middle pickups are.
I don't think you proved anything.
Have Fun,
T

Look more closely... that's an A5 bar sitting directly on the strings. If that doesn't induce magnetization, nothing will. The metal guitar string are no more or less paramagnetic over the frets than it is the bridge, middle, etc.

[big_teee]

Please read note 311, and 323 again.
Your test has nothing to do with that.
Later.
T