K240 Studio Headphones A electric guitar pickup is basically much like an energetic mike coil. For decades, dynamic microphones have been wired with the style coil attached to the principal of the microphone's transformer, and not recommended to ground (‘floating'). The microphone's situation is typically connected to the wire shield, that will be connected to the mike amplifier's floor (see Rane's site for more discussion).
By and large, powerful microphones are extremely quiet units consequently of the mix of transformer solitude and balanced, suspended transmission lines throughout, along with guarded, humbucking coils.
Therefore why not instruments? Instruments are notoriously affected by noise. Humbucking pickups are merely an incomplete (though important!) solution. The obvious answer would be to float practicing the guitar collection to a balanced production, just like a microphone. A similar thought was printed this 2001 patent application like this K240 Studio Headphones?