Help Identifying Magnet Types?

Mr. Lime

Mr. Lime

New member
Hi folks,

as I have swapped some magents over the last couple of years I have some laying around with no clue what types they are.
Is there any way to differentiate AlNiCo from ceramic magnets?
I tried to measure the resistance with my DMM.

I guess the bright looking ones are AlNiCo 5 with ~0.4 Ohm. At least I remember I shoud have one or two from TB-4/SH-4 conversions.
The one with the blue mark should be an A5 from a Duncan Full Shred I reacently swapped but it's looking different and reads open on the DMM - so this one seems no conductive, which I rather expected from ceramic?!

The dark big blocks are different as well. I think they are from a Duncan Distortion and a Duncan Designed Invader knock off but one reads 900k while the other shows open on the DMM.

What's your guess or how can I identify them else?

Magnets.jpg
 
Mr. Lime said:
Hi folks,

as I have swapped some magents over the last couple of years I have some laying around with no clue what types they are.
Is there any way to differentiate AlNiCo from ceramic magnets?
I tried to measure the resistance with my DMM.

I guess the bright looking ones are AlNiCo 5 with ~0.4 Ohm. At least I remember I shoud have one or two from TB-4/SH-4 conversions.
The one with the blue mark should be an A5 from a Duncan Full Shred I reacently swapped but it's looking different and reads open on the DMM - so this one seems no conductive, which I rather expected from ceramic?!
Click to expand...

Yes it is.

The dark big blocks are different as well. I think they are from a Duncan Distortion and a Duncan Designed Invader knock off but one reads 900k while the other shows open on the DMM.

What's your guess or how can I identify them else?
Click to expand...

Both are ceramic as shown by their color and resistance measurements...

There's certainly other ways to identify magnets but they require some lab gear:

-a Gaussmeter or Teslameter will measure a strong magnetic field on most ceramic mags, decreasing according to the grade of AlNiCo (A8 > A5 > A4 > A2 > A3 as long as the magnets are normally charged);

-an inductance meter will show an inductivity increasing in a reverse order comparatively to what is said above: a pickup with ceramic has less inductance than the same PU with AlNiCo and the weaker the AlNiCo is magnetically, the more inductivity it brings (the most inductive being A3... if all magnets have comparable sizes and mass).

FWIW. :-)
 
I started writing the typ on it with the A5 from the Full Shred but then got confused by it's color.
The Full Shred is an old pickup, probably from 80s or 90s but it looked original. Do you guys think they had put in a ceramic magnet instead of an A5?!?

Both are ceramic as shown by their color and resistance measurements...

There's certainly other ways to identify magnets but they require some lab gear:

-a Gaussmeter or Teslameter will measure a strong magnetic field on most ceramic mags, decreasing according to the grade of AlNiCo (A8 > A5 > A4 > A2 > A3 as long as the magnets are normally charged);

-an inductance meter will show an inductivity increasing in a reverse order comparatively to what is said above: a pickup with ceramic has less inductance than the same PU with AlNiCo and the weaker the AlNiCo is magnetically, the more inductivity it brings (the most inductive being A3... if all magnets have comparable sizes and mass).

FWIW. :-)
Click to expand...

Thanks for the hint!
A friend of mine has an pickup winding machine with a Gaussmeter included.
Do you guys experience a big diffrence in the magnets you buy from various sources so testing each makes sense?
If so which gear would you recommend for the pickup requirements?
Inductance- or Gaussmeters start at 50$ but I suppose they aren't sufficient?
 
My stash of non used magnets is meanwhile 30+. I test them with an gaussmeter and with my ears. A lot of them don't meet the specs. Some of them can't charged high enough, some loose their charge very fast and are not stable, but most of them don't charge evenly over the length.
 
Duncan puts a particular color pen on the end edge of different types. Addiction FX actually writes the type on the face with black sharpie.

The black brittle ones are ceramic (at least I've often had small little shards of it break off when swapping if I'm not careful). Shiny metallic would be Alnico, though roughcast Alnico will be a darker gray.

I hadn't heard of measuring resistance on a mag before, but I guess that is a way to rule out ceramic vs alnico. I don't know how you could figure out the actual Alnico grade without destroying it to determine it's composition (but I'm not a metallurgy or magnet expert either). But if you install them in the same pickup and listen for the relative differences, you might be able to categorize what they might be.
 
Mr. Lime said:
I
Thanks for the hint!
A friend of mine has an pickup winding machine with a Gaussmeter included.
Do you guys experience a big diffrence in the magnets you buy from various sources so testing each makes sense?
If so which gear would you recommend for the pickup requirements?
Inductance- or Gaussmeters start at 50$ but I suppose they aren't sufficient?
Click to expand...

You're welcome.
Yes, there's differences IME between magnets from various sources (mags of a "same" AlNiCo from different suppliers being able to give noticeably different tones, exactly like a given magnet can open to totally different sounds once paired to different coils from various winders).
Bbut as said by Hamerfan, magnets are very inconsistent things anyway. My explanations above were about averaged measurements, whose global consistency is far to deny the inconsistency of individual magnets...

Regarding testing gear: the DER DE-5000 costs less than 100 bucks and appears to give reliable LRC measurements. :-)
 
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