Hello, I was doing some recordings near the laptop, no amp involved whatsoever, with various guitars over the last weeks, and noticed that : 1) EMG 81 is more prone to low freq magnetic fields 2) EMG 85 is well quieter than the 81 under the same low freq magnetic fields conditions 3) Dimarzio Blazes, Super Dist and Air Norton are quiet regarding low freq fields 4) EMGs and Dimarzios are not affected that much by high freq (radio) 5) Dimarzios are affected by static electricity , i.e. approaching a shirt or hand close to the coil 6) EMGs behave better regarding static fields.
I've not had similar experiences, but then again I haven't tried that many pickups. One question though, are these pickups all installed in one guitar, connected to the same electronic network of volume and tone, or in different guitars? I'm assuming the former. If so, then it's probably simple construction. Different wire guages, number of wraps, magnet material, internal shielding, etc all either contribute or hinder possible electromagnetic pathways for noise to weasel into your signal. Remember, a coil is an inductor, which tends to dampen high frequencies, but all that wire in so close company can act as a capacitor of sorts as well, especially with larger wire gauges (they call that "parasitic capacitance"... look it up). Both high and low frequency noise can be alleviated (to one degree or another) by encasing your pickup in a shield (like any humbuckers covered by a metal housing), but that tends to spread out the magnetic field and lower pickup sensitivity. Ya pays yer money...
What I DO know is that single coils pick up EVERYTHING. That said, now that I've levelled up and gotten LCD monitors, the single coils in my '82 Fender Bullet are nice and serene, even with a flourescent shop light overhead. I also have a Squier Strat that only had two pickups when I bought it, so I converted the two to humbucking and stuck them next to each other in the bridge position, and that's pretty quiet as well. The cheap chinese Firebird-style mini-humbuckers I got recently are dead quiet; so much so that I hear the sound card noise before I hear hum or buzz from the pickups.
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