Paul Reed Smith Bass A best guitar collection is basically much like an energetic microphone coil. For many years, vibrant microphones have been wired with the voice coil attached with the primary of the microphone's transformer, and maybe not recommended to floor (‘floating'). The microphone's case is typically connected to the cable guard, which is connected to the microphone amplifier's ground (see Rane's site for more discussion).
By and big, dynamic microphones are extremely quiet products as a result of the mix of transformer isolation and balanced, flying transmission lines throughout, as well as protected, humbucking coils.
So why don't you guitars? Instruments are notoriously overwhelmed by noise. Humbucking pickups are just a partial (though crucial!) solution. The most obvious solution is always to float practicing the guitar pickup to a balanced output, being a microphone. An identical idea was printed that 2001 patent request such as Paul Reed Smith Bass?