I've lost count of the number of times I've seen people asking about specialist boutique winds to get a specific sound, and then it turns out the players they are trying to sound like just used generic stock pickups. This goes for single coils, humbuckers, P-90s, everything.
There's no magic faerie dust. Putting one company's or person's name on the baseplate of a pickup doesn't make it sound any different to how it did five seconds before. As long as your magnets and wire are the same, you get the same sound. If Fender make one Stratocaster pickup with A5 pole magnets and .42 wire wound to 7k, and Seymour Duncan also make a Stratocaster pickup with A5 pole magnets and .42 wire wound to 7k, and you put them in the same guitar with the same set up and played by the same person through the same amp and effects, the sound you get is the same.
If you compare pickups which actually have reasonable differences in construction—say, A2 magnets compared to A5—then you
will hear a difference, though how
significant that difference may be depends on the variation in construction and the kind of tone you use. The more gain and effects you use the less you're going to notice small differences between pickups. Bigger differences can still be clearly heard, but they'll still be covered up to an extent. If you're playing clean or low-gain blues then you will hear a difference between a single coil made with A2 magnets and one made with A5 magnets, but something like .42 wire wound to 7k and another one wound to 7.2k won't be obvious.
My general rules of thumb are:
- Magnet shape and arrangement make an obvious audible difference no matter what sound you use. Bar magnets vs pole magnets, three chunky bars vs one skinny bar, etc. 99% of single coils use pole magnets so this one shouldn't be much of a concern to you.
- Coil arrangement and connection makes the second-most obvious difference. Series humbucker, parallel humbucker, big single coil, skinny single coil, etc.
- Overall winding makes the third-most difference, but isn't always totally obvious. High gain or lots of effects can cover up the differences between an overwound and underwound version of a pickup; a clean sound will make this difference very obvious. The wire
type rarely matters simply because it's so rare to see pickups made with extremely different wires unless they're also very different in other ways anyway, at which point you must compare the pickups as a whole and can't single-out just the wire gauge.
- Magnet material is up next. AlNiCo, ceramic, neowhatsitsname (I just woke up; I'll remember after I've had my coffee...). Even just medium gain or light effects can disguise some of the differences between some magnet materials (A2 to A3, or A4 to A5, for example), but you can usually still just about tell them apart. Since single coils are almost always either A2 or A5, and those two magnets are very different-sounding, magnet material certainly does matter in single coil pickups. (Humbuckers aren't quite as distinct and come in more in-between varieties.)
If you're mostly playing clean then all these things will be apparent. You want to make sure you get the magnet arrangement, coil arrangement, winding, and magnet material all right for your style. For a 'normal' Strat single coil this will be something like the examples I've used above; A5 pole magnets and .42 wire wound to around the 7k mark, +/- 0.5k. Which specific model of pickup you may buy isn't going to make a whole lot of difference as long as those parts of the construction line up. If that kind of spec doesn't work out for you then buying another, similar-spec pickup isn't going to help; you'll want to shift more dramatically, such as trying A2 magnets, a much hotter or cooler wind, etc.
Bear in mind some abstract pickup designs can throw all this off, by using very unusual wire gauges to coil combinations to make DC readings which don't follow normal standards, or using very strange magnet arrangements. But typically if you were looking at one of those pickups you'd be well aware of it; you're unlikely to be 'tricked' into buying a blade magnet hum-cancelling Strat pickup. (Take one look at the
SD Hot Stack and you'll instantly see how hard it is to confuse it with a regular single coil.)
