Fuzzy bending, and not in a good way.

[nicholaspaul]

Try going "open circuit" with one coil instead of shorting it out and see what happens.

Also, you can bang on a supposedly dead humbucker coil without there being some kind of magnetic coupling from the core of the "deadened" coil to the other coil. You've got relative motion going on there.

Pardon my ignorance but what do you mean by relative motion?

[David Schwab]

Is that due to the poles not being the magnets or different magnets being used? Can a humbucker of sorts not be made with one half as a single coil, or even both, like the StagMag from Seymour Duncan?

Not just the poles. Look at Strat pickups; you either have the vintage style with alnico poles, or the import style with steel poles and ceramic magnets. They sound a little different, but not all that much.

Half a humbucker is not wound the same as a typical single coil, and the geometry of the coil is different. Strat pickups are taller and usually have more wire on them. You can make a humbucker with taller bobbins, and then tap the coil, so when you want the single coil tone, you use the full winding on that coil, and then less windings for the humbucker tone.

Do you find neos suit bass pickups more than guitar pups?

I use them for both, depending on what tone I want. I'm getting ready to introduce some guitar pickups, and some of them use neos. I also make bass pickups with ceramic and alnico magnets.

[Mike Sulzer]

Not just the poles. Look at Strat pickups; you either have the vintage style with alnico poles, or the import style with steel poles and ceramic magnets. They sound a little different, but not all that much.

I think quite a bit of manipulation of other parameters would be required to get pickups with steel and alnico cores to sound the same. I think in general that does not happen, and they sound different. Many people dislike the steel core imports, expecting them to sound like Fenders. I see noting to dislike necessarily, just different pickups for different purposes.

Let's see why the difference. This pair of measurements uses a coil wound on a plastic bobbin of single coil shape. It holds alnicos, or humbicker steel cores, a bit loose. The most striking difference is in the height of the peak. The eddy current losses in the steel are much greater than in the Alnico.

The low frequency inductance of the alnico coil is 0.47 of the steel coil. This is a result of the higher permeability of the steel. In the absence of increased
eddy current losses in the steel, the ratio of resonant frequencies would be about .69 (the square root). It is actually about 0.82, showing that the eddy currents have a significant effect on the frequency response. This is more complicated than just lowering the inductance at higher frequencies as the curvature in the yellow line shows. The yellow line is derived by removing the effect of the coil capacitance from the measured impedance. Without eddy current losses, this would just be the grey dashed line, the impedance of the coil (Lcoil) extended across frequency. The effect is much greater with steel coils than alnico. The green line shows eddy current losses; with no such losses, it would just be the gray dot-dash line. With the steel cores, these losses change significantly over the width of the resonance. Taken together the "yellow" and "green" effects mean that the shape of the resonance is not just like that of a simple RLC circuit

Eddy current losses have a profound effect on the response of pickup, and they help explain the differences in the sound of alnico and steel core pickups.

[ScottA]

The pole piece, being the core of the inductive sensor, is the single most important component of the "voice" of the pickup.

Approaching an order of magnitude more important than the coil.

As Mike outlines above, it is the eddy current loss properties and permeability of the core that define this voice, and specifically their effects on the way the frequency response is filtered.

[David Schwab]

I think quite a bit of manipulation of other parameters would be required to get pickups with steel and alnico cores to sound the same. I think in general that does not happen, and they sound different. Many people dislike the steel core imports, expecting them to sound like Fenders. I see noting to dislike necessarily, just different pickups for different purposes.

Let's see why the difference. This pair of measurements uses a coil wound on a plastic bobbin of single coil shape. It holds alnicos, or humbicker steel cores, a bit loose. The most striking difference is in the height of the peak. The eddy current losses in the steel are much greater than in the Alnico.

The low frequency inductance of the alnico coil is 0.47 of the steel coil. This is a result of the higher permeability of the steel. In the absence of increased
eddy current losses in the steel, the ratio of resonant frequencies would be about .69 (the square root). It is actually about 0.82, showing that the eddy currents have a significant effect on the frequency response. This is more complicated than just lowering the inductance at higher frequencies as the curvature in the yellow line shows. The yellow line is derived by removing the effect of the coil capacitance from the measured impedance. Without eddy current losses, this would just be the grey dashed line, the impedance of the coil (Lcoil) extended across frequency. The effect is much greater with steel coils than alnico. The green line shows eddy current losses; with no such losses, it would just be the gray dot-dash line. With the steel cores, these losses change significantly over the width of the resonance. Taken together the "yellow" and "green" effects mean that the shape of the resonance is not just like that of a simple RLC circuit

Eddy current losses have a profound effect on the response of pickup, and they help explain the differences in the sound of alnico and steel core pickups.



[ATTACH]30202[/ATTACH] [ATTACH]30203[/ATTACH]

Could you try doing the attachments again? I'd like to see them.

I agree the two pickups sound different, and I'd expect them to sound different for the reasons you cited, but in a Strat they still sound like a Strat. The alnico pickups have more of that ice pick brightness. In my Parker P-38, the two alnico single coils ended up being too bright when I tried to get a good humbucker tone from the bridge pickup (which was a darkish sounding humbucker). On a Mexican Strat I have here, the two ceramic/steel single coils blend better with the bridge humbucker. And they are still mighty bright. The owner wanted fuller sounding blade humbuckers.

I solved the Parker problem by replacing all three pickups.

But getting back to my point, half a steel poled humbucker still doesn't sound like a steel poled Strat pickup. Partly because it's under wound.

[Mike Sulzer]

Of course. I do not know where they went. They worked for me after just after I posted the message. Remember that the resonances will move down into the a more critical range when the cable capacitance is added and more turns are used on the coil. To me, the difference between alnico and steel cores (that is, metal inside the coil) is one of the bigger differences. Outside the coil, such humbucker magnets with different types of alnico, not as much.

steelCores.pdf alnicoCores.pdf

Could you try doing the attachments again? I'd like to see them.

I agree the two pickups sound different, and I'd expect them to sound different for the reasons you cited, but in a Strat they still sound like a Strat. The alnico pickups have more of that ice pick brightness. In my Parker P-38, the two alnico single coils ended up being too bright when I tried to get a good humbucker tone from the bridge pickup (which was a darkish sounding humbucker). On a Mexican Strat I have here, the two ceramic/steel single coils blend better with the bridge humbucker. And they are still mighty bright. The owner wanted fuller sounding blade humbuckers.

I solved the Parker problem by replacing all three pickups.

But getting back to my point, half a steel poled humbucker still doesn't sound like a steel poled Strat pickup. Partly because it's under wound.

[Mike Sulzer]

OK, the attachments in the previous message are working for me. Let me know if you have trouble.

[nicholaspaul]

I see. I understand that there are a lot of parameters at play in a pickup. I don't fully expect any humbucker to sound dead like a single coil, but getting close would be nice.

. You can make a humbucker with taller bobbins, and then tap the coil, so when you want the single coil tone, you use the full winding on that coil, and then less windings for the humbucker tone..

Now there's an interesting idea. Are you thinking that is should still have one bar magnet for both coils?

[nicholaspaul]

OK, the attachments in the previous message are working for me. Let me know if you have trouble.

Yup they work fine. Thanks. I wasn't going to reply earlier because the subject is way over my head and didn't want to jump in with rookie questions. I should go and read "guitar pickups for dummies" or whatever precedes that before I start bugging the experts...
If I'm just at the experimenting stage, should I be concerned with eddy currents, or are my problems like to be elsewhere for some time, like worrying about wire tension and other basics?

Thanks again.

[David Schwab]

---

OK, the attachments in the previous message are working for me. Let me know if you have trouble.

This is what I see:



Clicking on a link leads to this:

[Mike Sulzer]

They still work fine for me, and they worked for NP. I have no idea why you cannot get to them.

---

This is what I see:

[ATTACH=CONFIG]30287[/ATTACH]

Clicking on a link leads to this:
[ATTACH=CONFIG]30286[/ATTACH]

[Mike Sulzer]

Actually I see files names, you just see attachment numbers. So there is a difference, but I do not know what causes it.

---

This is what I see:

[ATTACH=CONFIG]30287[/ATTACH]

[David Schwab]

Actually I see files names, you just see attachment numbers. So there is a difference, but I do not know what causes it.

I don't know, and I also don't see the attachments when I click on the link.

On the other hand you can see the attached image in my post. What kind of files are they?

[Mike Sulzer]

I see; you need to click on the attachments in the post where I said I fixed it (8 26, 4:09 PM). Do you see the pdf files there? Those in the original post are gone; I do not know why.

(I know no way to fix broken attachments, just post new ones.)

[nicholaspaul]

How on earth did a post from 29 August appear after a post made on 1 September?!