Alnico Magnet Strengths - confused

[Tonequest]

A well known and respected pickup maker told me that Alnico 4 is the weakest of the alnico magnets, and that strength order (weakest to strongest) is as follows, with ceramic magnets the most powerful.

A4, 3, 2, 5, ceramic magnets

This has confused me somewhat, because I always believed it went in numerical order - i.e A2 being the weakest, followed by A3 and so on.

Can anyone clear this up for me?

 

[Indyclone]

a ceramic 8 is actually less powerfull than an alnico 4.... but yeah, an alnico 4 is weaker than a 3 which is weaker than a 2... but a 5 is stronger than 2,3,4 and even the 8.

 

[kevinT]

Here is some test results that I did a while ago. I am posting them so you can see the strength of different magnet grades. I used the Carlsen Melton gauss meter to measure the strength of the magnet before (as I received them from the vendor) and after charging to a full charge with my magnet charger.

The sizes of the magnets are the typical 2.5 x .5 x .125 bar magnets for humbuckers

To get a representative sample, I picked 3 mags from various orders that I received or I chose them from the same shipment of mags but various positions within the brick (i.e. end of brick, middle of brick, and some in between). I took 3 readings and used the highest reading. On some mags, I took a couple more readings when the numbers were unclear.


A2
Before Charging (as they came) / Full Charge
1. 554 North 486 South / 627 North 671 South
2. 533 North 493 South / 635 North 671 South
3. 446 North 457 South / 626 North 630 South

A3
Before Charging (as they came) / Full Charge
1. 407 North 461 South / 531 North 534 South
2. 407 North 465 South / 554 North 533 South
3. 414 North 438 South / 541 North 543 South

A4 Suppliers were out of stock when I placed order, sorry

A5
Before Charging (as they came) Full Charge
1. 491 North 567 South / 927 North 930 South
2. 611 North 598 South / 786 North 801 South
3. 765 North 747 South / 721 North 796 South

A6
Before Charging (as they came) Full Charge
1. 644 North 621 South / 768 North 741 South
2. 721 North 605 South / 838 North 915 South
3. 633 North 576 South / 740 North 756 South

A8
Before Charging (as they came) / Full Charge
1. 1171 North 1253 South / 1370 North 1494 South
2. 1216 North 1336 South / 1469 North 1407 South
3. 1297 North 1288 South / 1355 North 1368 South

Ceramic 5
Before Charging (as they came) Full Charge
1. 1251 North 1259 South / 1251 North 1291 South
2. 1252 North 1269 South / 1255 North 1287 South
3. 1297 North 1210 South / 1293 North 1210 South


Ceramic 8
Before Charging (as they came) / Full Charge
1. 1211 North 1216 South / 1219 North 1274 South
2. 1141 North 1190 South / 1197 North 1221 South
3. 1195 North 1204 South / 1242 North 1199 South


What surprised me were the wide differences in the gauss of the A5s. This is probably one of the reasons why PAFs sounded differently.

 

[mrpesca]

Well there is a razor sharp picture. Thanks Kevin.

 

[zoork_1]

Thanks for sharing this info

/z

 

[Indyclone]

yeah thanks Kevin... guess I got ahold of some bad info...

 

[captcoolaid]

I came up with different readings but not by much. Then my charger just fried and I am now haveing to order charged and go from there.

 

[Zhangliqun]

I'm wondering if that 927/930 A5 is really an A5! Sounds more like A6 numbers.

Anyway, my understanding of the relative strength weakest to strongest: 3, 2, 4, 5, etc.

 

[captcoolaid]

I find that my 3 are a tad stronger in pull then my 2. And as far as the 5's go I have seen them as hi as 1000

 

[kevinT]

I've noticed the same thing. I've also noticed that pickups with an A3 in the neck are louder than A2 in the neck with a comparable DCR.

 

[captcoolaid]

Yep.