Impedances of a humbucker using different types of alnico

[marku52]

"Losses are not always proportional to frequency squared. " I was referring to the f^2 in the eddy current loss equation. Of course, you are right that the actual system losses would be a complex multi faceted thing. And this "The cores of a pickup sure do look like little secondaries with currents circulating near their surfaces. " is just brilliant.

[Joe Gwinn]

Warm= less highs. More lows would be "fat".

Transparent= more highs, maybe less mids.

These are the terms as used by most bass players.

But if the highs are too prominent, one again loses transparency, or rather, has icepick transparency.

I suppose it would be a good exercise to provide engineering definitions for these musical terms, to as much precision as is practical.

[Mike Sulzer]

"Losses are not always proportional to frequency squared. " I was referring to the f^2 in the eddy current loss equation. Of course, you are right that the actual system losses would be a complex multi faceted thing. And this "The cores of a pickup sure do look like little secondaries with currents circulating near their surfaces. " is just brilliant.

Thanks. That concept is from this discussion: A new model the impedance of a humbucker, compared to measurements .

The same concept should work for the magnet, even though it is not as geometircally appealing. We still have partial flux linkage and induced voltage resulting in current flow.

[Joe Gwinn]

Losses are not always proportional to frequncy squared. Consider an audio transformer, primary, secondary, and a resistive load. Consider using the primary as an inductor with a normal value of load resistance connected. The power dissipated in the load in this situation is an eddy current loss. Throughout the useful range of the transformer, this loss is close to constant. As the frequency get higher, the loss drops. You know it does, because the power transferred to the load drops as the frequency increases out of the range of the transformer. The reason it does is explained by the transformer model. The so-called leakage inductance is in series with the load, and as the inductive reactive increases, the voltage across the load resistor drops. The cores of a pickup sure do look like little secondaries with currents circulating near their surfaces.

Mike, we've been through this once or twice before. Eddy currents are not well described using lumped-element transformer theory.

marku52, if you want the story, search in the archives. No need to relive the debate here. But be warned there must be hundreds of postings.

[marku52]

Thanks, I'll go hunt in the achives, Interesting stuff.

[Mike Sulzer]

Mike, we've been through this once or twice before. Eddy currents are not well described using lumped-element transformer theory.

You never showed that for the case under discussion, pickup cores. In fact, it is hard to see how it could fail when the eddy currents in question are just like secondary currents in a transformer. That is kind of like saying that transformer theory does not work for transformers.

Also, the model was able to reproduce the measurements with good accuracy.

Looking at this more broadly, the impedance of something must always be representable by lumped impedances in an approximate manner. It might take a lot of them, in some cases, to get it accurate, but not in this case. You can model a transmission line by lumped elements; why not this?

If you do not want to debate this, why bring it up? If you do intend to debate it, please bring something more solid to the table than "I do not believe it."