M Audio Keystation 61 A guitar pickup is essentially much like a dynamic microphone coil. For many years, active microphones have already been sent with the voice coil attached to the primary of the microphone's transformer, and not called to ground (‘floating'). The microphone's situation is normally attached to the cable shield, which will be connected to the mike amplifier's floor (see Rane's web site for more discussion).
By and big, dynamic microphones are extremely calm products consequently of the combination of transformer solitude and healthy, flying transmission lines during, in addition to protected, humbucking coils.
So why not instruments? Instruments are notoriously plagued by noise. Humbucking pickups are just a partial (though important!) solution. The most obvious option would be to float practicing the guitar collection to a balanced output, being a microphone. An identical thought was printed that 2001 patent application like this M Audio Keystation 61?