How/why do magnets make a difference?

Sporky McGuffin

Sporky McGuffin

New member
Hallo. I know little about magnets (other than that steel sticks to them). As such, while I'm happy that different magnets do result in a different sound (all other factors being equal), I have no idea why.

Could someone give me a basic explanation for how different magnet materials result in a different pickup sound please? Ta. :)
 
Re: How/why do magnets make a difference?

same way capacitors made from different materials make different sound. I've discovered that just changing the material of the capacitor even at the same value can make vast improvements.

Yeah, I don't have any real answers I'm afraid. I guess it's because they pull the steel in different ways.
 
Re: How/why do magnets make a difference?

Caps I understand - different materials affect the parasitic inductance and variation in value with frequency and so on.

Magnets I don't!
 
Re: How/why do magnets make a difference?

The shape and intensity of the magnetic field varies with different Alnico and ceramic grades so they read (and thus emphasize) different parts of the string (which have different parts of the frequency spectrum on them) to different degrees.
 
Re: How/why do magnets make a difference?

Zhangliqun said:
The shape and intensity of the magnetic field varies with different Alnico and ceramic grades so they read (and thus emphasize) different parts of the string (which have different parts of the frequency spectrum on them) to different degrees.
Click to expand...

Not to be a Walters, but the field of a stronger magnet presesnts a larger magnetic field for the plucked string to disturb?:?:
 
Re: How/why do magnets make a difference?

From my observation the major factor is the shape of the magnetic field that causes the noticeable and recognizable differences between the different Alnicos.

Of course other factors come on top. Quite obviously the compression when you play harder from ceramic isn't field shape based but some kind of saturation effect.
 
Re: How/why do magnets make a difference?

I'm surprised that no one has mentioned that the output voltage is directly proportional to field strength. The stronger the magnet, the higher the output - all other things being equal.
 
Re: How/why do magnets make a difference?

ArtieToo said:
I'm surprised that no one has mentioned that the output voltage is directly proportional to field strength. The stronger the magnet, the higher the output - all other things being equal.
Click to expand...

True, and the larger collapsing field (on each half wave) that is generated with a ceramic magnet, might also be responsible for impeding the same frequencies of said pickup.

Really, I'm not trying to be Walters!:D
 
Re: How/why do magnets make a difference?

The original question was about tone rather than output. I think folks intuitively understand that stronger magnet = higher output, but why differing grades of Alnico that are not outrageously far apart in field strength (or even when they have the same field strength due to partial degaussing of the stronger magnet) have significantly different tonal personalities.
 
Re: How/why do magnets make a difference?

The strength really isn't that important. The only Alnico much stronger is A8.

A weak A2 still sounds like A2, just "less so", same for A5.

The only weakness similarity that I found is that A3 sound to be like weak A5. Might be the particular A3 magnet I have.
 
Re: How/why do magnets make a difference?

All this magent talk has me thinking. What classifies a magnet to be an A2, A5, A8? What are the spec differences and how can they be measured? Can you tell which is which just by looking at them?

I'm very curious.

Thanks.
 
Re: How/why do magnets make a difference?

Zhangliqun said:
The original question was about tone rather than output. I think folks intuitively understand that stronger magnet = higher output, but why differing grades of Alnico that are not outrageously far apart in field strength (or even when they have the same field strength due to partial degaussing of the stronger magnet) have significantly different tonal personalities.
Click to expand...

True, but I believe, (and I stress "believe"), that tonal characteristics are directly related to output. I doubt that the interaction between L, R, and C are linear in a guitar/pickup circuit.

77CUSTOM said:
All this magent talk has me thinking. What classifies a magnet to be an A2, A5, A8? What are the spec differences and how can they be measured? Can you tell which is which just by looking at them?

I'm very curious.

Thanks.
Click to expand...

The "A" number is derived from when the material was invented/discovered. Thats why magnet strength doesn't follow "A" numbers. For example, A2 is stronger than A3, but A5 is stronger than A8.

Here's a good read. Especially check out the chart on page #7:

magnetics.pdf
 
Re: How/why do magnets make a difference?

I use two different types of pole magnets .One lot are Ferrous Oxide and the other are a "rare earth" type. The FeO's are bright and clean tone.What i would call"full and round".The Rare earths are very bright[top endy]and sound "metallic"[not as in head banger music].Both are fairly strong types of magnets.Alinco's are a compound which would appear to tone down the top end and "metallic"[as in sound] qualities of singular metal type magnets.
 
Re: How/why do magnets make a difference?

Rats! Where is that Michael Faraday when we really need him?
 
Re: How/why do magnets make a difference?

Different alloys of the metal used to make them. See the table at this link:

http://www.salvarsan.org/content/alnico.html

Alnico magnets range from 29% to 65% iron. The rest is some combination of ALuminum, NIckel and CObalt (hence the name "ALNICO"), plus a tiny bit of copper and/or titanium. Alnico 3 has no cobalt in it -- so you could make a case for calling it ALNICU -- while Alnico 4 has no copper. Alnico 3 and 4 both have a good deal more iron than most other grades. And Alnico 6, 8 and 9 have titanium, and use much less iron and more cobalt than the other grades.

As you can see, there are also some variations on Alnico 5 and 8, and don't ask me to explain them. All three A5 variations appear to have identical ratios of the various metals, maybe the process of mixing or charging them is different.

As for telling them apart visually, I can't do it. A3 might look a little different because of the lack of cobalt but it would be just too close to call, so I mark all mine with a sharpie.

77CUSTOM said:
All this magent talk has me thinking. What classifies a magnet to be an A2, A5, A8? What are the spec differences and how can they be measured? Can you tell which is which just by looking at them?

I'm very curious.

Thanks.
Click to expand...
 
Re: How/why do magnets make a difference?

People forget that the induction is the countereffect for the varying magnet field. When string vibrates it modulates the magnetic field that is around it and the modulation is being stopped by creating an opposite force. The force is actually a magnetic field that is opposite to the field being modulated. The field is generated by a current being inducted to the coil of the pickup. Since the coil is "open"(referenced to ground) along with the current there is a voltage potential inducted to the coil of the pickup, which is actually based to the resistance of the coil(U=RI). The pickup thus literaly picks up the vibrations of the string.

Few things can be seen from the forementioned explanation
1. the resistance of the coil DOES affect the voltage being inducted
2. the magnetic force(intencity of the field) affects the voltage being inducted
3(not actually mentioned before) but the number of windings affect the voltage and current being induced so that more windings=more current= more voltage= more power from pickup= less sustain. Yes more windings lead to faster decay of the string vibration.

The difference of the magnets lie within the magnets structure; how it is magnetized. Different magnets have different magnetic structure and magnetic properties and that is what makes all the difference. The modulation current also induces forces to the magnet which also induces current to the windings(crosstalk) which makes the difference between materials.
 
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