#1
Today I came home and looked in my box of totally random guitar parts. I pulled out an old stock pickup out of an Ibanez Rg 270 I believe. I decided that this pup had no worth to me so I tore it to pieces to examine the quality. When I got down to it, there was one small magnet touching all 12 poles of the humbucker. This thing was half a cm thick and the poles all were barely touching it. My understanding was that each coil should have a separate magnet, am I wrong or is this common? If this is common, why does this pup suck and others (like my dimarzios I replaced it with) rock?

I do not know what the magnet is made of, this was an exploratory surgery.
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#2
No, that's what you call a bar magnet. Some pickups use individually magnetised polepieces, some use one or more larger magnets underneath.

The magnet you've got is almost certainly going to be a low-grade ceramic magnet. The higher cost of aftermarket pickups is mostly justified by the quality control and the materials used, plus attention to detail with things like wax potting and the way the pickup wire is wound.
#3
Humbuckers almost always use bar magnets. Good single coil pickups use 6 indevidual poles but unfortunatly most single coils being made are not very nice either so they use steel poles and 1 ceramic bar magnet. Most P90's use 2 bar magnets.
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