Allen Heath Mixer A electric guitar collection is essentially similar to a dynamic mike coil. For decades, active microphones have been wired with the voice coil mounted on the primary of the microphone's transformer, and not referenced to surface (‘floating'). The microphone's case is typically connected to the cable shield, that is attached to the mike amplifier's floor (see Rane's web site for more discussion).
By and large, active microphones are extremely quiet units as a result of the mixture of transformer solitude and balanced, flying transmission lines all through, as well as guarded, humbucking coils.
So why not instruments? Instruments are notoriously affected by noise. Humbucking pickups are just an incomplete (though crucial!) solution. The obvious solution is always to move practicing the guitar pickup to a healthy output, being a microphone. The same idea was published that 2001 patent application such as Allen Heath Mixer?