Zildjian K Custom Hybrid A best guitar pickup is actually similar to a vibrant microphone coil. For decades, vibrant microphones have now been wired with the voice coil attached with the principal of the microphone's transformer, and not referenced to floor (‘floating'). The microphone's event is usually attached to the cable guard, which is connected to the mike amplifier's soil (see Rane's website for more discussion).
By and big, active microphones are very quiet devices as a result of the mix of transformer isolation and balanced, hanging indication lines all through, in addition to shielded, humbucking coils.
So why don't you guitars? Guitars are notoriously plagued by noise. Humbucking pickups are only a partial (though important!) solution. Well-known option is to float your guitar pickup to a balanced output, just like a microphone. The same idea was published this 2001 patent request like this Zildjian K Custom Hybrid?