Steel Acoustic Guitar A electric guitar pickup is actually just like a powerful microphone coil. For decades, powerful microphones have been wired with the style coil mounted on the principal of the microphone's transformer, and perhaps not recommended to ground (‘floating'). The microphone's event is usually linked to the wire guard, which can be connected to the mike amplifier's floor (see Rane's web site for more discussion).
By and large, active microphones are very quiet devices as a result of the mix of transformer isolation and balanced, hanging sign lines throughout, as well as shielded, humbucking coils.
So why don't you instruments? Instruments are notoriously affected by noise. Humbucking pickups are merely an incomplete (though essential!) solution. The most obvious alternative would be to float the guitar collection to a healthy output, being a microphone. A similar idea was published this 2001 patent program like this Steel Acoustic Guitar?