Identifying magnets

[Benjy_26]

Hello all.

I'm wondering if there's a quick and easy way to ID magnet types. I ask because I've got a set of single coils in my strat that came out of an Ernie Ball Albert Lee sig. They're listed as APS-3's, and I'd like to know if there's a difference in magnet type between these pickups and the standard APS's.

Thanks a bunch!

 

[AlexR]

Re: Identifying magnets

Fully saturate the magnet and read its gauss is the only reliable way.

Some makers put marks on bar magnets in certain colours, but I'm not sure if there is any consistency with such markings.

 

[ItsaBass]

Re: Identifying magnets

There is not a "quick and easy" way, unless you know that a certain user of the mags (i.e. a certain pickup maker) makes some sort of marks to differentiate them, and you know what those marks are.

Type doesn't matter so much as gauss anyhow, so that is the best way to see what you're working with. Within the same pickup design, what you are really hearing when you hear differences between types is just differences in strength, not differences in alloy composition.

 

[AlexR]

Re: Identifying magnets

There is not a "quick and easy" way, unless you know that a certain user of the mags (i.e. a certain pickup maker) makes some sort of marks to differentiate them, and you know what those marks are.

Type doesn't matter so much as gauss anyhow, so that is the best way to see what you're working with. Within the same pickup design, what you are really hearing when you hear differences between types is just differences in strength, not differences in alloy composition.

Not according to the findings of winders. For example one winder I know has done testing on this - and amongst them he talked to me about a degaussed A5 to typical A2 level (from the same supplier) and he found definitively its not the same at all......if what you're trying to say is that strength is the only tonal difference in mags.

 

[ItsaBass]

Re: Identifying magnets

Not according to the findings of winders. For example one winder I know has done testing on this - and amongst them he talked to me about a degaussed A5 to typical A2 level (from the same supplier) and he found definitively its not the same at all......if what you're trying to say is that strength is the only tonal difference in mags.

That within the same exact pickup design, magnetic strength is what causes the tonal differences we hear, is *mostly* true. But there are some caveats. The big one is that the statement is made assuming identical magnetic permeability of the mags. In reality, the differing magnetic permeability of the alnico grades, which affects the shapes of the respective magnetic fields that they establish, affects how each grade magnetically couples with the strings.

A2/3/4 are more magnetically permeable than A5. This means that they want to "hold on to" the magnetic field more tightly; the field hugs the magnet more closely than it does with A5's. This creates slightly different (more "withdrawn") magnetic field shapes that A5, regardless of gauss. This results in increased inductance within the pickup itself, but in the end, reduced output vs. A5. This is because A5, with its larger field, is more strongly coupled to the strings, even though its lower permeability (i.e. less dense, more widespread magnetic field) results in coils with lower inductance. Thus, A2/3/4 will still be [just a bit] in a league of their own compared to A5; they will result in less output, *even if* A5 and, e.g. A2 are gaussed exactly the same.

This is all considering the case in which A2 and A5 are matched in strength. But in the real world, they are not. So you take the slight differences in output caused by the differences in permeability when strength is equal...and add in the fact that in real-world application, their strength is *not* equal, and you have an even larger tonal difference, caused simply by the increased magnetic strength. This leads to even more additional output (much more than the difference in permeability causes), which in turn dramatically affects how an amp responds to an A5 magnet, vs. the lower powered alnico varieties.

So...no, it's not only as simple as magnetic strength...but in the real world, it pretty much is. So much so, that we can say that it basically comes down to magnet strength.

 

[Ayrton]

Re: Identifying magnets

Slightly related thought...

We all know that magnet formulas varied wildly for decades, but given what guitar manufactures know today, are specific formulas consistently used?

I know some like Suhr or ThroBak uses a specific magnet formula and supplier, but do say Duncan and DiMarzio? One of the reasons we covet old Duncans so much was the magnets used at that time.

 

[Aceman]

Re: Identifying magnets

That within the same exact pickup design, magnetic strength is what causes the tonal differences we hear, is *mostly* true. But there are some caveats. The big one is that the statement is made assuming identical magnetic permeability of the mags. In reality, the differing magnetic permeability of the alnico grades, which affects the shapes of the respective magnetic fields that they establish, affects how each grade magnetically couples with the strings.

A2/3/4 are more magnetically permeable than A5. This means that they want to "hold on to" the magnetic field more tightly; the field hugs the magnet more closely than it does with A5's. This creates slightly different (more "withdrawn") magnetic field shapes that A5, regardless of gauss. This results in increased inductance within the pickup itself, but in the end, reduced output vs. A5. This is because A5, with its larger field, is more strongly coupled to the strings, even though its lower permeability (i.e. less dense, more widespread magnetic field) results in coils with lower inductance. Thus, A2/3/4 will still be [just a bit] in a league of their own compared to A5; they will result in less output, *even if* A5 and, e.g. A2 are gaussed exactly the same.

This is all considering the case in which A2 and A5 are matched in strength. But in the real world, they are not. So you take the slight differences in output caused by the differences in permeability when strength is equal...and add in the fact that in real-world application, their strength is *not* equal, and you have an even larger tonal difference, caused simply by the increased magnetic strength. This leads to even more additional output (much more than the difference in permeability causes), which in turn dramatically affects how an amp responds to an A5 magnet, vs. the lower powered alnico varieties.

So...no, it's not only as simple as magnetic strength...but in the real world, it pretty much is. So much so, that we can say that it basically comes down to magnet strength.

Except that everything you just said states that it is BOTH magnet type and magnet strength. Plus winding.


Talk yourself in contradictory cirrcles much?!?!?! :chairfall

 

[Chistopher]

Re: Identifying magnets

This is really quite the informative thread. One thing that I would like to add for posterity is that you can check what grade a bar magnet is if you have another known magnet to compare it with. It's what we often call "the fridge test" and it's simply pulling the magnets off of a bigger magnet and comparing how much force is required to do so.

If you have an A5 magnet and the other magnet is a lot easier to pull off, it is either an A2 or A3, most likely an A2 given how common they are.

 

[metalchurch79]

Re: Identifying magnets

Roughcast vs polished is also quite apparent by visual inspection, correct?

 

[DavidRavenMoon]

Re: Identifying magnets

Fully saturate the magnet and read its gauss is the only reliable way.

Some makers put marks on bar magnets in certain colours, but I'm not sure if there is any consistency with such markings.

I agree about needing to read a fully charged magnet. That’s what I do.

Some of the marks on magnets are just to tell which side is North.

At DiMarzio (which makes Earnie Ball pickups) they have a magnet glued to the to of a filing cabinet. They stack a bunch of bar magnets stuck together and stick it too the magnet on the cabinet. Then they run a magic marker across the ends of the magnet.

I never saw different color markers used. But maybe other makers do that.


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[Mincer]

Re: Identifying magnets

I was always under the impression those pickups were specifically made for the Albert Lee, which is a remarkable guitar. I am not sure how they are different than the APS-2s.

 

[ItsaBass]

Re: Identifying magnets

Except that everything you just said states that it is BOTH magnet type and magnet strength. Plus winding.

That is *not* my point at all. Read better. I say there's more difference between A5 and others, based on permeability...but that the differences in strength dominate.

 

[Benjy_26]

Re: Identifying magnets

I was always under the impression those pickups were specifically made for the Albert Lee, which is a remarkable guitar. I am not sure how they are different than the APS-2s.

That's what I've been reading as well. A friend of mine replaced the pickups in his EB Albert Lee with a pair of CR's and a JB Jr and gave them to me. I then proceeded to install them in my MIJ 62 RI strat. They are EXTREMELY clean and have a ton of sparkle to them. They'll do the Knopfler sound easily if you do your part.

From what I can see, they're flat poled with slightly smaller diameter poles than Fender singles and SSL-1's and the bridge has a steel plate embedded in the bottom.

Some guys on the EB/MM forum have implied that they may be alnico 3, and I've beem trying to confirm that.

 

[DavidRavenMoon]

Re: Identifying magnets

A2/3/4 are more magnetically permeable than A5. This means that they want to "hold on to" the magnetic field more tightly; the field hugs the magnet more closely than it does with A5's. This creates slightly different (more "withdrawn") magnetic field shapes that A5, regardless of gauss.

Permeability is a material’s ability to conduct magnetic lines of force. So air has a permeability of 1, and iron is about 6.3.

So your steel pole pieces are permeable.

Magnetic fields extend forever, but drop in strength with the square of the distance.

So assuming we are measuring the magnets fully charged at a fixed distance from the magnet, an Alnico 5 will have the residual induction (Br) of around 12,200 Gauss, while Alnico 2 is around 7,000.

The field of a stronger magnet might seem to extend further, but it doesn’t. It’s just that the weaker magnet’s field is weaker at the same distance.


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[Aceman]

Re: Identifying magnets

That is *not* my point at all. Read better. I say there's more difference between A5 and others, based on permeability...but that the differences in strength dominate.

Yes - but magnet STRENGTH is not just about the strength. An A2 and an A5 - IF they were the same strength would sound different. You [to the best of my knowledge] can't really separate the two - strength/type.

Oh - by the way -

https://forum.seymourduncan.com/showthread.php?238750-How-do-different-magnets-actually-affect-tone

 

[ItsaBass]

Re: Identifying magnets

Yes - but magnet STRENGTH is not just about the strength. An A2 and an A5 - IF they were the same strength would sound different. You [to the best of my knowledge] can't really separate the two - strength/type.

Oh - by the way -

https://forum.seymourduncan.com/showthread.php?238750-How-do-different-magnets-actually-affect-tone

I said as much! But it's a matter of degrees. The slight difference between A5 with the strength of A2, and A2, is due to differences in permeability between the two alloys. Again, this is not a huge difference, though there is one. Incorporate the fact that A5's are usually used in the real world fully magnetized, and you have a much, much more extreme tonal affect via the difference in strength than you do via the difference in permeability.

And when you get into A2 vs. A3 and A4, the slight differences become even more slight, because their differences in permeability are less than them vs. A5.

So, bottom line, the overwhelming affect on tone comes via differences in magnet strength.

 

[jeremy]

Re: Identifying magnets

sooo... this is about single coil pups with alnico rod magnets. all this bar magnet talk, while fine, is of little use to the op. my understanding is that the albert lee came with aps pups, alnico 2 magnets. i think the bridge pup has a bottom plate but maybe that was a customization on the one i worked on

 

[Benjy_26]

Re: Identifying magnets

sooo... this is about single coil pups with alnico rod magnets. all this bar magnet talk, while fine, is of little use to the op. my understanding is that the albert lee came with aps pups, alnico 2 magnets. i think the bridge pup has a bottom plate but maybe that was a customization on the one i worked on

It makes for interesting reading, but you are correct. It has little bearing on the APs set in thr Albert Lee. FWIW, that steel plate is a feature I've seen in every Albert Lee pickup during my research.

 

[Lewguitar]

Re: Identifying magnets

Very informative thread.

I do my experimenting with magnets mostly in my PRS guitars. Two CU22’s and three SE Singlecuts.

I’m a bluesy rock player with a good knowledge of chords and harmony and play in alot of different styles.

The pickup sets I’m using in my favorite humbucker guitars are Duncan 59’s and Antiquitys. I swap the stock magnets for Roughcast A3 in the neck pickup and Roughcast A2 in the bridge pickup.

With RCA3, I’m getting the clarity without the muddy bass that I’ve always wanted from a neck humbucker.

With RCA2, I’m getting the thick snarly, harmonically rich Clapton, Beck and Mick Taylor overdrive tones I loved when they plugged their Gibsons into Marshalls and turned it up in the 1960’s.

I also like the sound of alnico 4 and have RCA4 Antiquitys that I modified in a PRS Singlecut. I like that tone alot. Its a little more elegant, more refined, less splashy and tighter sounding than my A3/A2 sets. I much prefer it to the bright, scooped and woofy sound of A5 in 59’s.

 

[ItsaBass]

Re: Identifying magnets

sooo... this is about single coil pups with alnico rod magnets. all this bar magnet talk, while fine, is of little use to the op. my understanding is that the albert lee came with aps pups, alnico 2 magnets. i think the bridge pup has a bottom plate but maybe that was a customization on the one i worked on

I was not talking about any particular type of pickup, but magnets in general. The bit about differing permeability applies to alnico pole piece magnets. A2/3/4 have similar permeability, and maximum strength of the magnet is almost entirely what is causing each have "its tone". A5 is a little brighter and higher in output, even when gaussed the same as an A2/3/4...but not a ton. And in the real world, in which A5's are almost alway used fully charged, not taken down to A2 level, then the difference in strength is the main differentiating factor in tone vs. A2/3/4.

The initial point I was making was simply that measuring the gauss is really ("really" not meaning "only," but "largely") what the OP needs in order to understand the technical specs of his pickup magnets. Knowing the name of the magnet type used isn't as important as knowing it's strength. You measure the gauss, and you know whether you have a relatively strong or relatively weak magnet. That's pretty much all you need to know to basically understand what the magnet is doing in that particular pickup.