Room Tone Sound Effect A guitar pickup is essentially just like a dynamic mike coil. For decades, energetic microphones have been sent with the voice coil attached with the principal of the microphone's transformer, and perhaps not introduced to soil (‘floating'). The microphone's situation is usually linked to the wire shield, which is attached to the microphone amplifier's floor (see Rane's web site for more discussion).
By and big, active microphones are very calm products as a result of the mixture of transformer isolation and balanced, suspended sign lines throughout, as well as guarded, humbucking coils.
Therefore why not instruments? Guitars are notoriously overwhelmed by noise. Humbucking pickups are only a partial (though crucial!) solution. Well-known solution is to move the guitar collection to a healthy output, as being a microphone. A similar thought was printed that 2001 patent request like this Room Tone Sound Effect?