Use Multi-Section Windings to Reduce Self-Capacitance

[Mike Sulzer]

How much Flux is generated by current? And: I don't know, if that is your "retoure-hit" at me, but: Telling somebody, he is stupid, wouldn't improve things at all. I already apologized to you for my language. I do it again. So: Can we now move over to EE again? I did't want to hurt you, if it is that, what you want to tell me.

Please help me again, in understanding your thoughts.

We are so far accord with the fact, that the magnetized/or permeable guitar string does something to the field. My understanding is, that the string changes the properties of an otherwise static magnetic field. I always thought, that this change is being picked up by the coil. You tell me, i am wrong. I am worried. Please explain in more detail, where i am wrong and why.

Thank you very much.

And: I would be very thankful, if you would consider giving me another chance of a friendly conversation between us two.

Thanks again.

The field from the magnetized string adds to the original field from the permanent magnet. But it is better to forget about the original static field from the magnet and just concentrate on the part from the magnetized string, because it is what varies with the string vibration, and thus causes changing flux through the pickup coil, which then induces the voltage by Faraday's law. We can do this because fields can be considered the sums of other fields as long as no material is close to saturation, as could happen in an audio output transformer, for example.

This is the last reply I can make today because I have to leave this computer, and my laptop is broken.

[Antigua]

And also to you Antigua: Sorry for the escalation. I am sure, you are a pretty cool guy. Was my fault. Sorry. I should have behaved better. You are right.

Back to your thesis: Ever considered AlNiCo Magnet Poles in your explanation above?

I understand, that you point out, that a permanent magnet hasn't really a "permeability". It is a permanent magnet.

I also understand that a Ferrite (non-permanent magnet) has huge permeability, but no own magnetism in a sense of a permanent magnet.

But: Does this play a role here? The poles just conduct the flux of the permanent at the bottom. You could also omit the ceramic on the bottom and use -whatever- polepieces you like. AlNico or Ceramic - as far as i know, this plays only a secondary role (eddy currents are different as well as saturation flux).

All other things being equal, a highly permeable steel pole pickup is louder than a lowly permeable ALNiCo pole pickup, and both are louder than an air coir pickup, and this is because the permeability of the core will enhance the amount of flux change through the coil, as the string moves nearer and farther from the pole pieces, therefore creating more voltage. The fact that the pole pieces in question also supply a residual flux, which the magnetic guitar string exploits, can be ignored in the analysis. For example, suppose the pickup had no magnet at all, and instead you held a magnet above the pickup, or suppose the string itself was a permanent magnet. The analysis would be the same.

* actually, for the sake of accuracy, it does change the analysis if the permanent magnet is moved to another location, in that the string would have a different total flux charge, depending on it's distance at any given moment from that permanent magnetic source, but that's a minor point and can be ignored. There hysteresis curve of the steel guitar string would also factor in, but that's getting even more trivial.

[Bagpipe]

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[Antigua]

Lets simply omit miller effect here and only talk about additional parallel capacitance. You may or may not be right with your thesis, that you may improve tone a bit with reducing self capacitance. I think we go in accord (all) that we can expect the difference to be very small - probably not to be heard by people like me, or people with a similar ear.

I haven't read your whole reply yet, and might have to leave for a while, but over on another forum where this stuff is discussed it was generally thought that if the pickup had a lower capacitance, the pickup would remain brighter as the volume was rolled off, since the pickup's capacitance would be isolated with its inductance, which speaks to the value of reduced C, which is on topic for this thread, and you're saying none of that matters vaguely because of Miller effect, so you're not just rebuffing my point, but that made by others, so if you're correct, that would be important, but it would also require thorough reasoning.

You said " but its influence is usually high enuff to swallow self capacitance of the pickup." I'm not sure what you mean "swallow" the pickup's capacitance. Does it dampen the LC resonance? Change the value of C?

[Helmholtz]

And what happens to miller effect?

Just for information and maybe lowpass calculation:
The typical input capacitance of classic (12AX7) tube amps is around 150pF including the Miller effect and internal wiring. This just adds to the cable's (and PU's) capacitance.
Any active electronics between guitar and amp will isolate from the amp's input.

[Antigua]

Sorry Antigua, but my opinion varies.

A highly permeable steel pole is only louder than Alnico's because the Permanent Magnet at the bottom is stronger. And this force is transferred with pretty good efficiency by the steel slugs. The AL Value of AlNiCo isn't very good compared to permanent ferrites. That is why -subjectively- Alnico sounds "weaker" than ceramic+steelcores.

This is what I mean by you having to admit you're assuming too much. You're stating as fact something which is demonstrably incorrect. AlNiCo poles are much stronger than steel poles with an undermounted magnet. This is evidenced, for example, by "Stratitus" where AlNiCo 5 pulls so hard that it causes the string to lose pitch. This really only ever happed with AlNiCO 5, because it is distinctly strong. I recommend buying one of these so that you can see for yourself https://www.amazon.com/Gaussmeter-Fl...ds=tesla+meter

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[Antigua]

Just for information and maybe lowpass calculation:
The typical input capacitance of classic (12AX7) tube amps is around 150pF including the Miller effect and internal wiring. This just adds to the cable's (and PU's) capacitance.
Any active electronics between guitar and amp will isolate from the amp's input.

When you turn the volume control of a 250k pot down to where there is, say, 125k ohm series resistance between the pickup and amplifier, is either the miller effect or the 150pF input C impacting the LC resonance of the guitar pickup?

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[Antigua]

Just for the record:
Stratitis works different, than you described it - at least according to seymore duncan.

It has nothing to do with "string pull" and "losing pitch".

It is slightly more complicated.

I know a lot about Stratitus. It does impact the pitch. I wrote a post about it here Analyzing the "wolf tone" effect in a spectrogram | GuitarNutz 2

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[Helmholtz]

When you turn the volume control of a 250k pot down to where there is, say, 125k ohm series resistance between the pickup and amplifier, is either the miller effect or the 150pF input C impacting the LC resonance of the guitar pickup?

Easy to simulate. The Miller effect just shows in the increased input C. Nothing else to consider. Without the Miller effect the input C would be around 50pF.

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