Replacement Magnets For Pickups

[Jeff_H]

Apologies if this has been covered. I'm familiar with how to swap magnets and the properties of different grades, but I don't know much about where magnets are made and how much difference country of origin or chemical makeup effect the magnet as a whole.

I'm aware of the typical sources of replacement magnets like AddictionFx and a couple of others. What I wanted to know specifically is if there is a source to obtain magnets like Seymour used to use in the late 70's through mid 80's; the very black and rough magnets as found in the old JB's, 59's, PG's and so on, before the change to the smooth sided polished magnets in use today? Magnets from the time when the old pickups sounded just a little different than they do today.

Is it enough to simply have a rough cast magnet to replicate the old SD magnets, or does color and country of origin play a part too? One last question. Are there different levels of rough cast magnets; some rougher than others?

Thanks.

 

[raistlin]

Re: Replacement Magnets For Pickups

Apologies if this has been covered. I'm familiar with how to swap magnets and the properties of different grades, but I don't know much about where magnets are made and how much difference country of origin or chemical makeup effect the magnet as a whole.

I'm aware of the typical sources of replacement magnets like AddictionFx and a couple of others. What I wanted to know specifically is if there is a source to obtain magnets like Seymour used to use in the late 70's through mid 80's; the very black and rough magnets as found in the old JB's, 59's, PG's and so on, before the change to the smooth sided polished magnets in use today? Magnets from the time when the old pickups sounded just a little different than they do today.

Is it enough to simply have a rough cast magnet to replicate the old SD magnets, or does color and country of origin play a part too? One last question. Are there different levels of rough cast magnets; some rougher than others?

Thanks.

Given that rough casts have a slightly different magnetic field to polished magnets, I wonder if SD modified the wind to compensate?

If not, they would sound slightly different, wouldn't they? I can imagine getting a couple of roughcasts A5 in my 59 set.

 

[Jeff_H]

Re: Replacement Magnets For Pickups

Yes, I'm just wondering if the difference between the 70's/80's magnets is just rough cast or if there is more to it than that. I know it's a subject the company wont elaborate on. I'm also not sure if windings were altered to compensate for the new magnets or not? I somewhat doubt it, because using the JB as an example, the company has stated that the wind today is the same as it was in the beginning, but early models clearly sound different than current models.

I just wanted to experiment with magnets if the old type were still available somewhere.

 

[Discharged]

Re: Replacement Magnets For Pickups

Different countries have different composition standards that go with different alnico grades, plus there can be audible differences between sintered and cast magnets from the same foundry and alnico grade, not to mention the differences between batches of production, due to variation of purity of the scrap materials used.

Contrary to popular belief, there's no specific differences between magnets that can be attributed to surface finish. The surfaces touching the keeper bar and the slugs are ALWAYS POLISHED (grinded), so, if the rest of the other surfaces are not, it makes absolutely NO MEASURABLE DIFFERENCE. When roughcast mags are used in conjuction with relatively soft bobbins, specifically butyrate, they may help strenghtening the mechanical side of the assembly as a vibrating unit, specially if unpotted and covered.

The "standard" for PAFs are the formulae based on the MMPA 0100_00 document, that are the accepted definitions for the different alnico grades, produced in the 50a and 60s by Thomas & Skinner, which in reality is a military contractor, producing bar magnets for p'ups by custom order only.

Having said that, there are several up-to-date, ISO 9000 compliant alnico foundries in China, with mass-spectrometers and computer-controlled annealing processes, which will reproduce the hysteresis curves of any magnet, vintage or modern, american or not, adjusting the whole process to accurately match the B/H curves of the sample/s provided.

I've personally used these capabilities to make vintage mags repros of A2s, A3s, A4s and UOA5s, having provided original samples. All of this comes with a cost, but nowhere close to Thomas & Skinner's original request.

The biggest offender in reproducing vintage tone is PAF repros is undoubtly Alnico 4. That's because is actually NOT RECOGNIZED as standard Alnico, due to the proprietary nature of the original formula, covered by Intellectual Property laws, but mentioned in page 25 of the MMPA 0100_00 document: "APPENDIX A: PERMANENT MAGNET MATERIALS NOT COVERED IN PRODUCT SECTIONS". I don't know for sure what foundry came up with it, although vox populi suggests the original source being Arnold Magnetics, IL.

/Peter