Pickup theory question

[David Schwab]

Last night I showed you that it does matter, and now you respond to a days old post, not the one from last night. Thank you for the response at last, but I would have felt better if you had responded to the post from last night.

Well I didn't get a chance to read everything, so I had missed that post. Also I responded to that last night, not today. Well maybe early today, but it was during the same posting session.

You showed what mattered? You lost me here. Maybe I need to read everything again.

Anyway, my point was, have you wound a humbucker and swapped the A5 for an A2? I told you that I did this, and first it had a big ceramic magnet. The tone changed more than the output. The most dramatic output change was from the ceramic to the A2, but it wasn't huge. But it did take an unpleasant edge off the pickup. I can't find the sound clips for that one.

But here's another real life example. This is a dual rail Strat sized pickup installed in the neck position. This is not as drastic as C8 to A2 however.

This was recorded direct. I use using a clean Twin patch in my Roland VM-3100 digital mixer. I had the levels a little hot.

First you hear it with a C8 magnet. This magnet reads 740G on the North pole.

Ceramic

Next is a small neo which reads over 1500G. At that point my meter goes out of range.

Neo 1

It's a different tonality than the ceramic, with a little more low end.

Next is a much larger neo. I didn't even try reading that directly.

Neo 2

Now that one is a little louder. But not a whole lot.

To try and get a reading on the two neo magnets (until I build the second probe for my meter) I used a 0.08" plastic spacer.

With the spacer I get 645G for the C8, 690G for the small neo and 1450G for the large neo.

Here's the waveforms. You can see the two neo magnets have more output, but what you hear is a lot less drastic.

Ceramic



Neo 1



Neo 2

[salvarsan]

Duhhh...

If a guitar pickup produces a measurable voltage and current,
duzzat mean it has a power output?

Like, y'know, power = voltage X current, or P = VI?

And if power P = energy E per time unit ( E/dt),
does that mean the pickup has an incremental energy output?

Naaah.

Idle conjecture, flawed logic, nope, neither energy nor power in a pickup,
nope, never, zero, zilch, zip, nada, negatori.

Furthermore, screw Maxwell.
Embrace the Heaviside.

[FunkyKikuchiyo]

Being fundamentally interlinked and the SAME THING are two different things, David. You're losing yourself in details and equivocation. Dualities are very complicated and you can't ever just put an equals sign in the midst of that - otherwise we wouldn't have any distinctions between electricity and magnets. We could discuss the particle/wave duality of light all we want, but it wouldn't help us decide if my neon shirt is battery powered. You're changing your arguments as you learn more... that is fine, but please don't come back and tell us how stupid we are when you started by saying that magnets store and provide the energy for a pickup, when the energy itself comes FROM THE STRING. The laws of conservation of energy tell us that if the magnet PROVIDED the energy, the magnet would eventually drain. Do you ever have to change your magnets? If you leave your bass plugged in over night, does it drain the magnets the way a 9v preamp will get drained when you leave it plugged in? The absolute, most basic law of physics is that you can't make something from nothing, be it energy or matter. I'm talking about the forest, and you've skipped right over the trees and looking at the veins on the leaves.

So, where does the energy from the pickup come from? It comes from the player hitting the string. Typically this comes from refined sugars in candy bars accelerated by red bull. Espresso in the case of jazz players. That was my original, fundamental point on why measuring "output" is highly subjective. Add to that that I have only seen one person present data that used a consistent pickup height (which showed a near linear correlation, albeit not passing through zero) and you are left with data that is mostly useless in a discrete fashion.

Descartes in all of his skepticism of empirical data never seemed to have problems with conservation of energy, if his air pressure experiments were any indication, by the way. Though, Pascal had that experiment down a bit earlier to my understanding... so perhaps be should be talking about probabilities instead?

[Steve Conner]

The sad thing is, espresso doesn't have any calories in it. (Sad, because it means I have to put milk in it to survive.)

Dave, thanks for the pickup samples, and the pickups sound nice, but they are digital clipped to hell and back! I think your amp model is clipping and compressing the signal too. If you recorded those completely clean and undistorted, I bet the ones with stronger magnets would have considerably bigger waveforms on the display, and sound louder, too. In short, I think the tonal changes you're hearing come from the amp model reacting to the increased drive, transforming volume changes into tonal changes, and that feeds into the "Best amp for testing pickups?" thread.

[big_teee]

This Post has been Very Entertaining!
Rock on!
Terry

[Dave Kerr]

OK, I'll be the one to ask the obvious. David S's magnets were measured at the poles - did you try taking a reading at string height?
:ducking

[Rick Turner]

Now for a different viewpoint.

I've believed since I started making pickups that the shape and density of the magnetic field as it relates to the string and the position and shape and depth of the coil is very important to tone. Change anything in the magnet(s) or pole pieces and you'll change the three dimensional dynamic interface among the strings, coil(s), and magnetic circuit.

And David, yes, I was the one who came up with the Alembic "Hot Rod" kit in 1973 for juicing up humbuckers with Ceramic V magnets. Blame that on on me!

The biggest problem with jacking up magnetic strength is "Stratitis"...the braking effect of the magnetic pull on the strings.

You want more output without adding turns or putting in stronger magnets? Wind flatter coils with more turns closer to the strings. It might even be worth trying to design ultra thin bobbin flanges or even putting self supporting coils that don't need that thickness of the bobbin material. You might even be able to wind coils with fewer turns of thinner wire where all the turns are closer to the strings than with conventional pickups.

My earliest pickups were bobbin-less. Might have to try that again.

[David Schwab]

You're changing your arguments as you learn more...

I'm not changing a thing. The devil is in the details. You are showing you really don't understand electricity or magnetism.

that is fine, but please don't come back and tell us how stupid we are when you started by saying that magnets store and provide the energy for a pickup, when the energy itself comes FROM THE STRING.

What I said was, without the magnet you have no current. The magnetic field is required to get the kinetic energy from the string into current in the coil. If nothing is moving, no electricity is formed. But that's true of everything. Everything is moving. That also provides us with time.

Remove the magnet and strum the strings. What do you have? Nothing. What's missing? The magnet. So on their own the strings cannot induce current in the pickup coil. So what is the magnet doing in the circuit?

The laws of conservation of energy tell us that if the magnet PROVIDED the energy, the magnet would eventually drain.

So why don't magnets lose their power when they sit over night? If they were holding a change, like a battery, they might. But they don't. They are generating the magnetic field. They might, and probably will drain after a very long time. No one is implying perpetual motion here.

But that in itself is not electricity, but it is energy. And the relationship between magnetism and electricity is why you get the current in the coil.

Some other things you said that are in error are:

No energy ever comes from a passive pickup.

I'll quote Dan:

"If a guitar pickup produces a measurable voltage and current, duzzat mean it has a power output?"

A passive pickup is a small AC generator.

Magnets don't have energy, they just have polarity.

Polarity implies a charge. Charge implies energy potential. And in fact magnets do have measurable energy.

To quote Steve:

"magnets do have energy. If you multiply B (the flux density) and H (the MMF) together, the resulting number has units of joules per cubic meter, and it's called the "energy product" of the magnet."

The fact that two neo magnets can attract each other, move across quite a bit of distance, and smash into fragments requires energy. They can also remove your finger. They can also provide enough energy to overcome gravity.

Where's that energy coming from?

[David Schwab]

OK, I'll be the one to ask the obvious. David S's magnets were measured at the poles - did you try taking a reading at string height?
:ducking

No.

But I did supply a reading at a fixed space from the magnets. I didn't do that at the time because I'm working with magnet types that I use all the time. In all cases the pickup was adjusted the exact same height from the strings.

I was really interested in how each magnet sounded. In some instances the large neos made the tone very muddy. That was very surprising. A smaller neo cleaned up the tone. But then I rewound the pickup with a lot less turns.

But just for the heck of it, the small neo version is still in the guitar. I read 263G touching the top of the pickup, and 122G at the string height (with the string pulled out of the way).

[David Schwab]

The sad thing is, espresso doesn't have any calories in it. (Sad, because it means I have to put milk in it to survive.)

Add sugar.

Dave, thanks for the pickup samples, and the pickups sound nice, but they are digital clipped to hell and back! I think your amp model is clipping and compressing the signal too. If you recorded those completely clean and undistorted, I bet the ones with stronger magnets would have considerably bigger waveforms on the display, and sound louder, too. In short, I think the tonal changes you're hearing come from the amp model reacting to the increased drive, transforming volume changes into tonal changes, and that feeds into the "Best amp for testing pickups?" thread.

Yeah, they were clipped. But it was just for me, was quick and dirty, and I often end up clipping the signal a little because I can hear it better cranked up! When I just plug into the high-z input with no amp sim the sound is very dry.

I just do it as a reference while I'm working on a new pickup. That way I can hear them all the same time, and my memory wont be spotty on which one I liked or disliked.

I just recorded this now. Here's that neck pickup, DI, no EQ or effects. And also no clipping. Then I turned on the clean Twin patch.

Tele Neck

[Rick Turner]

You can't just measure magnet strength in one place and understand how the field...which is three dimensional...and the string...which moves dynamically in 3 D space interact with the coil which is more or less fixed in space.

Also, I hate to say it, but if you suddenly take the magnet away, there is some magnetism left in the string and the pickup "model" becomes solely and totally a moving magnet pickup. No more variable reluctance, no "disturbing the static field".

There was a lap steel made in the '30s or '40s that had a special amplifier. Flip a switch, and DC flowed up the cable to the pickup, and the pickup coil charged the strings. Flip the switch the other way, and signal flowed into the amp input. You had to recharge the strings frequently.

[FunkyKikuchiyo]

The sad thing is, espresso doesn't have any calories in it. (Sad, because it means I have to put milk in it to survive.)

I misspoke. I meant that jazz players substituted espresso for red bull in aiding the candy bars. I had forgotten that red bull was loaded with sugar and that I had a mismatch there. I don't drink that stuff. I stick to coffee. My music theory isn't quite good enough for espresso so it has largely just been drip, which is about right for blues scales and mixolydian stuff. If I have a dark roast, I can rock the major 7 chords and throw a 6 or 9 in there for color... but it has to be a good dark roast.

[David Schwab]

Also, I hate to say it, but if you suddenly take the magnet away, there is some magnetism left in the string and the pickup "model" becomes solely and totally a moving magnet pickup. No more variable reluctance, no "disturbing the static field".

Right, until you change your strings. It doesn't work very well either, but I'm sure you know that. It's one of those things you discover when you are a teenager messing with guitars.

There was a lap steel made in the '30s or '40s that had a special amplifier. Flip a switch, and DC flowed up the cable to the pickup, and the pickup coil charged the strings. Flip the switch the other way, and signal flowed into the amp input. You had to recharge the strings frequently.

Patent number RE20070, A. Lesti, from 1936.

RE20070_Lesti (electromagnet).pdf

[Mike Sulzer]

You showed what mattered? You lost me here. Maybe I need to read everything again.

I showed you that the output increases with the magnet strength (yesterday 10:23 PM, I believe), even when that strength is well beyond what a normal humbucker uses. You know, actual measurements shown with a graph.

I guess you have read Steve's comment on your clips. This is what I was talking about back there somewhere. If you clip the signal, when the output level goes up, it gets brighter without seeming to get that much louder. You said that that was not what you were doing, but then you showed that that is what you are doing. So no, I do not believe you when you claim that one Alnico is brighter than another or a ceramic is brighter because you are producing additional harmonics from the increased clipping.

But I will try to do the test, assuming I can get some magnets that are certainly the right grades. I think some places sell you whatever and tell you what you want to hear. Do you know where can I get a set of humbucker magnets of known Alnico types and same for ceramic?

[David Schwab]

I guess you have read Steve's comment on your clips. This is what I was talking about back there somewhere. If you clip the signal, when the output level goes up, it gets brighter without seeming to get that much louder. You said that that was not what you were doing, but then you showed that that is what you are doing. So no, I do not believe you when you claim that one Alnico is brighter than another or a ceramic is brighter because you are producing additional harmonics from the increased clipping.

That would be assuming that; 1) I never played the pickup except in a mildly clipped digital editor, one time each, and 2) that I haven't played any other pickups with different magnets. Why do you think they make humbuckers with alnico II magnets? Why not just used A 5 on everything. If it was only the output that changed it wouldn't make any sense.

The pickup I was originally talking about that went from ceramic to alnico was a bridge pickup in a different guitar and went on a bunch of gigs with one of the guitar players in a band I was playing in, and then played through a Fender Twin. So I know what the tones were like with each magnet in real world situations.

That guy didn't like the ceramic, and felt the tone was too harsh. He liked the alnico better, even though he didn't know I changed magnets. But he asked if I did something because the pickup had a warmer tone.

Mike, find a music store and try some different guitars. Pickup makers have been using different types of magnets to get different tones for years. This isn't anything new. DiMarzio even uses different thickness of ceramic magnets in different pickups to control the strength of the magnet.

And then of course they have that air gap patent:

The strength of the magnetic field is reduced a desired amount to achieve pleasing tonal quality...

By appropriate placing of the pole pieces on the retainer bar, the gap between the pole pieces and the magnet may be precisely determined. Different spacings may be selected to provide different tonal qualities.