Hartke Bass Combo A electric guitar pickup is actually just like a powerful microphone coil. For decades, dynamic microphones have been sent with the voice coil mounted on the principal of the microphone's transformer, and not referenced to ground (‘floating'). The microphone's event is usually linked to the wire shield, which will be connected to the microphone amplifier's ground (see Rane's website for more discussion).
By and big, dynamic microphones are extremely calm units consequently of the mixture of transformer isolation and balanced, flying transmission lines all through, as well as shielded, humbucking coils.
So why don't you instruments? Instruments are once plagued by noise. Humbucking pickups are merely a partial (though crucial!) solution. Well-known alternative is to float your guitar pickup to a healthy result, being a microphone. An identical strategy was printed this 2001 patent software like this Hartke Bass Combo?