Isotropic Magnets
- Thread starter The Usual
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Re: Isotropic Magnets
A1, 2, or 3 are usually considered isotropic...so buy a new one from the usual suppliers.
But 50's Gibson stuff also used A4, which is considered anisotropic...I would expect that there are a lot of old Gibsons with mixed A2 and A4, either in phase or out of phase magnetically (quite a few were OOP magnetically, esp. archtops).
A1, 2, or 3 are usually considered isotropic...so buy a new one from the usual suppliers.
But 50's Gibson stuff also used A4, which is considered anisotropic...I would expect that there are a lot of old Gibsons with mixed A2 and A4, either in phase or out of phase magnetically (quite a few were OOP magnetically, esp. archtops).
Zhangliqun
Questionologist
Re: Isotropic Magnets
A4 is isotropic too. A5 and A8 are anisotropic.
A4 is isotropic too. A5 and A8 are anisotropic.
Zhangliqun
Questionologist
Re: Isotropic Magnets
Sintered is just a different manufacturing technique where powder is crushed together. The magnets in pickups are cast though, not sintered.
I have heard of iso (non-oriented) A5, one manufacturer was sending out uncharged samples and I got a couple but couldn't get them to charge even a little so I never found out what they sound like.
Sintered is just a different manufacturing technique where powder is crushed together. The magnets in pickups are cast though, not sintered.
I have heard of iso (non-oriented) A5, one manufacturer was sending out uncharged samples and I got a couple but couldn't get them to charge even a little so I never found out what they sound like.
Natman
New member
Re: Isotropic Magnets
Ok I gotta ask, what is the point? Especially in a pickup, you NEED a directional magnetization. Please enlighten me! I have a materials engineering degree and I can't fathom why you would WANT an anisotropic magnet unless you're referring to the unmagnetized alloy. Sintered would be different.
Ok I gotta ask, what is the point? Especially in a pickup, you NEED a directional magnetization. Please enlighten me! I have a materials engineering degree and I can't fathom why you would WANT an anisotropic magnet unless you're referring to the unmagnetized alloy. Sintered would be different.
Zhangliqun
Questionologist
Re: Isotropic Magnets
Of course you need a directional magnetization. What non-oriented means is that you can easily flip the polarity of a magnet so that the end that was N becomes S and vice versa of course. Can't do this, or at least not easily, with anisotropics.
Of course you need a directional magnetization. What non-oriented means is that you can easily flip the polarity of a magnet so that the end that was N becomes S and vice versa of course. Can't do this, or at least not easily, with anisotropics.
Re: Isotropic Magnets
Thanks folks for all the responses. While you were helping out, I was doing some looknig on my own. It seems that the difference is in the heating and cooling down process. If it is cooled down in a magnetic environment, it is anisotropic, and if it is cooled in a non magnetic environment, it is isotropic. So in theory, you could make them at home. I think I may try.
As for the reason, I assume they will sound different. I am imagining a 5 or 8 isotropic.
While we are on the subject, I have Shaw pickups with A5s in them that have a rough, almost raw looking surface. They sound nothing like any other mags I have. They are actually really nice. Any idea what type of mags they are? Unpolished, or a different manufacturing process?
Thanks folks for all the responses. While you were helping out, I was doing some looknig on my own. It seems that the difference is in the heating and cooling down process. If it is cooled down in a magnetic environment, it is anisotropic, and if it is cooled in a non magnetic environment, it is isotropic. So in theory, you could make them at home. I think I may try.
As for the reason, I assume they will sound different. I am imagining a 5 or 8 isotropic.
While we are on the subject, I have Shaw pickups with A5s in them that have a rough, almost raw looking surface. They sound nothing like any other mags I have. They are actually really nice. Any idea what type of mags they are? Unpolished, or a different manufacturing process?
Natman
New member
Re: Isotropic Magnets
Hey Usual -when they're talking about heating & cooling it's likely to be during the casting stage, where the alloy is molten. That becomes a question of phase changes which is really complex. When the atoms "lock in" to their final resting place, they will often form a complex molecular (crystal) pattern. Many magnets will only work with a certain atomic arrangement which gets thrown off by phase changes during solidification or heat treatment. Anyway my point is you won't be able to make em at home, unless you've got some smelting equipment. If you want to know more, read up on the phase transformations of alnico and permanent magnets. I really don't believe that anisotropic mags will benefit your guitar pickups IMO. What's the point of being able to reverse the polarity? It sounds like what's currently available is all you would ever need to capture the sound you're after.
Last thoughts: ceramic mags are sintered FWIW. I suspect that the anisotropic mags would demagnetize more quickly too. That might be why Zhang had a hard time charging them? Heating any magnet high enough will throw off the magnetization, regardless of isotropy.
Hey Usual -when they're talking about heating & cooling it's likely to be during the casting stage, where the alloy is molten. That becomes a question of phase changes which is really complex. When the atoms "lock in" to their final resting place, they will often form a complex molecular (crystal) pattern. Many magnets will only work with a certain atomic arrangement which gets thrown off by phase changes during solidification or heat treatment. Anyway my point is you won't be able to make em at home, unless you've got some smelting equipment. If you want to know more, read up on the phase transformations of alnico and permanent magnets. I really don't believe that anisotropic mags will benefit your guitar pickups IMO. What's the point of being able to reverse the polarity? It sounds like what's currently available is all you would ever need to capture the sound you're after.
Last thoughts: ceramic mags are sintered FWIW. I suspect that the anisotropic mags would demagnetize more quickly too. That might be why Zhang had a hard time charging them? Heating any magnet high enough will throw off the magnetization, regardless of isotropy.
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Re: Isotropic Magnets
Well here's what I know. A1,2,3 and 4 are isotropic, or that's the common thoery out there by manufactureres. They are quite beneficial for guitar, as 2,3 and 4 are commonly used. Anisotropic are also quite useful, as currently that's how A5 and A8 are made. So both will work quite fine.
What I am chasing down, is the rumor that the original PAFs had iso A5s, which are very useful in some cases, given that everyone is falling over themselves to get back there.
As to whether or not I can make them in a bon fire in my back yard, I guess there's one way to find out! I'll probably do less reading, and more marshmallowing, but that's me!
Well here's what I know. A1,2,3 and 4 are isotropic, or that's the common thoery out there by manufactureres. They are quite beneficial for guitar, as 2,3 and 4 are commonly used. Anisotropic are also quite useful, as currently that's how A5 and A8 are made. So both will work quite fine.
What I am chasing down, is the rumor that the original PAFs had iso A5s, which are very useful in some cases, given that everyone is falling over themselves to get back there.
As to whether or not I can make them in a bon fire in my back yard, I guess there's one way to find out! I'll probably do less reading, and more marshmallowing, but that's me!
Zhangliqun
Questionologist
Re: Isotropic Magnets
Many of the original PAF's didn't even use A5's. Alnico 5 didn't come out until 1955, the year the humbucker was invented, which meant that Gibson likely was using up all their other A2/3/4 bar mag stock in 56-57 before they grabbed any A5. It's unlikely there even was such a thing as iso A5 back then.
Anyway, the point of chasing down some iso A5 is not so you can flip it, but to hear what they sound like.
Many of the original PAF's didn't even use A5's. Alnico 5 didn't come out until 1955, the year the humbucker was invented, which meant that Gibson likely was using up all their other A2/3/4 bar mag stock in 56-57 before they grabbed any A5. It's unlikely there even was such a thing as iso A5 back then.
Anyway, the point of chasing down some iso A5 is not so you can flip it, but to hear what they sound like.
Re: Isotropic Magnets
You are dead on. Have you ever heard of this before, in your building travels?
You are dead on. Have you ever heard of this before, in your building travels?
