My Alnico 5 Magnet Test

[tonedeciple]

In the past I have always used alnico 5 bars that come to me already magnetized for my humbuckers. However, I've often wondered what would happen in terms of tone if I charged/degaussed the magnets myself. So I did a test today.

First I made a test humbucker with 6,000 turns of 43 AWG SPN wire on both bobbins. Next I charged three A5s to around 950 gauss. Then I degaussed one down to 650 and the other to 550.

For the test, my goal was to determine the difference in tone for all three gauss levels. I did this by swapping out the magnets after playing the same chords and notes for comparison.

I was rather surprised when I discovered absolutely no difference in tone or sustain. All three A5s sounded exactly the same! In fact, I further degaussed one of the A5s down to 400. Still no difference. As a sanity check, I slid in a ceramic mag and once again, no change. Any Ideas about what may or may not be happening here?

[Possum]

...

950????? I"ve never seen an alnico 5 bucker bar hold a charge that high. Try this experiment on the neck instead. At 400 you should start getting a more soft tone....

[tonedeciple]

950????? I"ve never seen an alnico 5 bucker bar hold a charge that high. Try this experiment on the neck instead. At 400 you should start getting a more soft tone....

Cripes! 950! What was I thinking. I rechecked my notes and it was 830. I guess I shouldn't start a thread so late at night. Sorry about that.

I did the test with the pup in the neck position with identical amp settings and even down to 400 I couldn't detect any difference. I did notice the poles had far less string pull, which I thought would contribute to greater sustain, but I simply couldn't tell.

[David Schwab]

I have an A5 bar here that reads 800G, but all the rest are around 400.

You should try the test with a pickup wound a bit cleaner. You will hear a softer top end. With hot pickups you probably want a stronger magnet so it wont be muddy.

[tonedeciple]

Yesterday when I did the test, I would play and record the 830 mag, then the 650 mag and compare. Then I'd do the same with the 550 mag and compare to the 650. I was trying to see if the tone would suddenly change at a specific gauss. But nothing. So I did the 400 and compared it to the 550 and still nothing. This morning after reading the responses here, I compared the 830 to the 400. And yes, there is a subtle difference. The treble has been knocked back a bit.

I guess I was expecting a more dramatic affect. But, it's nice to know that fine tune the tone of a pickup with careful degaussing.

So, I would think the priority in designing a pickup should be:
1. The coil. Wire gauge, # of turns, tension and pattern.
2. The magnet. Composition and gauss
3. The materials. Bobbins, baseplate, keeper, etc.

[David Schwab]

Another approach, which is patented but interesting none-the-less, is what DiMarzio do. They stick a couple of plastic spacers on the four outside poles to stop the magnet from directly touching the poles... so the air gap simulates a degaussed magnet.

[tonedeciple]

Another approach, which is patented but interesting none-the-less, is what DiMarzio do. They stick a couple of plastic spacers on the four outside poles to stop the magnet from directly touching the poles... so the air gap simulates a degaussed magnet.

I'll have to do a cost/benefit analysis to see if it's feasible. Oh wait, I got into this because I couldn't handle the corporate world anymore!

[Mike Sulzer]

Why would you expect lowering the strength of the magnetic field to affect the tone of the pickup, unless you started out strong enough to have some effects due to string pull?

Weakening the field (at the string) causes less output. You can measure this. On the other hand, if your standard test involves a lot of distortion you will not notice much of a change in level, but might notice a change in the sound because you have changed the amount of distortion.

Yesterday when I did the test, I would play and record the 830 mag, then the 650 mag and compare. Then I'd do the same with the 550 mag and compare to the 650. I was trying to see if the tone would suddenly change at a specific gauss. But nothing. So I did the 400 and compared it to the 550 and still nothing. This morning after reading the responses here, I compared the 830 to the 400. And yes, there is a subtle difference. The treble has been knocked back a bit.

I guess I was expecting a more dramatic affect. But, it's nice to know that fine tune the tone of a pickup with careful degaussing.

So, I would think the priority in designing a pickup should be:
1. The coil. Wire gauge, # of turns, tension and pattern.
2. The magnet. Composition and gauss
3. The materials. Bobbins, baseplate, keeper, etc.

[tonedeciple]

Why would you expect lowering the strength of the magnetic field to affect the tone of the pickup, unless you started out strong enough to have some effects due to string pull?

I should have stated my assumptions were based on bits and pieces I've picked up here and there about how an A5's gauss can affect tone. Before I had a gauss meter I couldn't help but wonder if the bars I have been using (all were charged for me) might have varied wildly in their gauss levels and whether or not this would have an affect on tone. Since I have to test things out myself to see if there's any truth to an idea, I gave it a shot.

As I mentioned, there was a slight difference from full strength to a 400 gauss mag on a clean amp setting, but it was very small.

As I sell more and more pickups, I don't want to make claims that are far fetched or down right untrue. Had I not tested this idea, I probably would've faced a lot of guff if I were to state that "I carefully degauss each of my Alnico 5 magnets in order to dial in the perfect tone."

[David Schwab]

Why would you expect lowering the strength of the magnetic field to affect the tone of the pickup, unless you started out strong enough to have some effects due to string pull?

But it does, as does using something like an Alnico II magnet, which has a more mellow top end than an Alnico V.

It's a pretty standard thing actually. DiMarzio use the air gap and Duncan degausses the magnets. I'm sure the guys here do it too.

426-450 - Seymour Duncan/Basslines

426. What is "Dun-aged"?
This is a process I developed to calibrate various bar and rod magnets to a desired field strength. I artificially age or degauss magnets to obtain a certain tone and output from a pickup. I like winding vintage coils and using very weak magnetic fields. It helps soften the sound of an instrument that may be very bright sounding acoustically.

450. What will changing a magnet in my pickup do?
Changing the magnet can do several things depending on the magnet your replacing it with. If the magnet is stronger than the replaced one the output can be greater and brighter sounding. If the magnet is weaker than the original, the output can be less and the sound will be warmer. Often remagnetizing a row of single magnets or a bar magnet will make the sound brighter and harder sounding. If the magnetic field is too strong the notes can sometimes sound like glass shattering. Putting in strong ceramic magnets will make the pickup louder and brighter but will also dampen the string vibration and sustain. The strings can stick to the pole pieces when doing dive bombs with your whammy bar. I like to tone you get with weaker magnets and I spend much of my work week calibrating magnets for a desired tone.

[tonedeciple]

But it does, as does using something like an Alnico II magnet, which has a more mellow top end than an Alnico V.

It's a pretty standard thing actually. DiMarzio use the air gap and Duncan degausses the magnets. I'm sure the guys here do it too.

426-450 - Seymour Duncan/Basslines

Well, if Seymour can say it, then so can I!

[Mike Sulzer]

Well, if Seymour can say it, then so can I!

But what did he really say? Part of what he is describing is just string pull. Much of the rest of it is just what happens when you change the amplitude into a non-linear system. Does any of it really have to do with a difference in sound of the pickup due to changing the field strength?

There is another possibility that might explain a change in sound. An alnico magnet charged to saturation typically has a permeability of maybe 5, with some variation between different types of alnico. If you degauss it somewhat, you move along the B-H curve to where the permeability is higher. This gives a higher inductance and a less bright tone. But how big is this effect? With the short open pole pieces, the permeability affects the inductance less than with closed cores, but there is still some effect with a permeability of about 5. So I am not sure that this would do it or not.

[David Schwab]

But what did he really say? Part of what he is describing is just string pull. Much of the rest of it is just what happens when you change the amplitude into a non-linear system. Does any of it really have to do with a difference in sound of the pickup due to changing the field strength?

I don't think it has anything to do with string pull, but you can listen to the pickup with lower output due to the weaker magnet and then boost he level up the same as the fully charged magnet, and they will sound different at the same amplitude.

If I can share a recent experience, I was testing a prototype dual rail strat pickup recently. I used two 1 x 1/4 x 1/4" neo magnets just to see what I got. It was very loud, but also had an extreme emphasis on the low end.. a very bassy sounding pickup. I removed the two neos and used a 1 X 1/4 X 1/8" magnet, and the tone was much brighter and more open sounding. The output was about the same.

So changing from a stronger to weaker magnet did effect the tone. Was that from saturating the blades? I seem to remember someone posting here recently that it doesn't happen with neos. But the change in tone was huge.

You can get the same tonal effects with different ceramic magnets as well. DiMarzio uses a rather thin ceramic magnet for the neck version of the Evo and a thick one for the bridge.

[tonedeciple]

I'm attaching a couple of sound samples to demonstrate what I got going from 830 down to 400. I used a bit of gain since the clean setting was not as obvious. Please don't laugh at my playing skills!

[Electricdaveyboy]

Another approach, which is patented but interesting none-the-less, is what DiMarzio do. They stick a couple of plastic spacers on the four outside poles to stop the magnet from directly touching the poles... so the air gap simulates a degaussed magnet.

Had seen something interesting in a PAF style humbucker made by a well known american boutiqe winder.

He uses a shorter magnet that touches the keeperbar and leaves an airgap on the slug pole side.
Interesting for me because I always look for tight fit for best magnetic transfer on all components.