Old Accoustic Guitar A guitar collection is actually much like a dynamic mike coil. For decades, vibrant microphones have been sent with the voice coil attached to the primary of the microphone's transformer, and maybe not referenced to surface (‘floating'). The microphone's event is typically attached to the cable shield, that will be attached to the mike amplifier's ground (see Rane's web site for more discussion).
By and large, active microphones are very quiet devices consequently of the mix of transformer isolation and healthy, suspended sign lines for the duration of, in addition to shielded, humbucking coils.
So why don't you instruments? Instruments are once overwhelmed by noise. Humbucking pickups are only an incomplete (though crucial!) solution. Well-known answer is always to move the guitar collection to a balanced output, as being a microphone. A similar strategy was printed that 2001 patent program like this Old Accoustic Guitar?