Marching Snare Practice Pad A guitar pickup is essentially similar to a dynamic microphone coil. For decades, energetic microphones have already been wired with the style coil attached to the primary of the microphone's transformer, and not recommended to ground (‘floating'). The microphone's event is normally attached to the wire shield, which can be connected to the microphone amplifier's soil (see Rane's site for more discussion).
By and big, dynamic microphones are extremely quiet units consequently of the combination of transformer isolation and healthy, suspended transmission lines during, as well as shielded, humbucking coils.
So why don't you guitars? Instruments are notoriously affected by noise. Humbucking pickups are merely an incomplete (though crucial!) solution. The most obvious solution is to move practicing the guitar pickup to a healthy output, being a microphone. An identical idea was printed that 2001 patent program like this Marching Snare Practice Pad?