12 Powered Speakers A guitar pickup is actually similar to a dynamic microphone coil. For decades, energetic microphones have now been sent with the voice coil mounted on the primary of the microphone's transformer, and perhaps not recommended to ground (‘floating'). The microphone's situation is usually connected to the cable shield, which will be connected to the microphone amplifier's surface (see Rane's internet site for more discussion).
By and big, dynamic microphones are extremely calm products as a result of the combination of transformer isolation and balanced, suspended sign lines all through, along with shielded, humbucking coils.
Therefore why don't you guitars? Instruments are notoriously affected by noise. Humbucking pickups are only an incomplete (though essential!) solution. The most obvious option would be to float the guitar collection to a healthy production, as being a microphone. The same strategy was printed this 2001 patent request like this 12 Powered Speakers?