Power Amplifier Kelas A A guitar pickup is basically just like a powerful mike coil. For decades, active microphones have been sent with the style coil mounted on the primary of the microphone's transformer, and maybe not called to soil (‘floating'). The microphone's case is normally linked to the wire guard, which is attached to the microphone amplifier's ground (see Rane's website for more discussion).
By and big, energetic microphones are extremely quiet products consequently of the combination of transformer isolation and healthy, hanging indication lines all through, in addition to protected, humbucking coils.
So why not instruments? Instruments are once overwhelmed by noise. Humbucking pickups are just an incomplete (though important!) solution. The obvious alternative is always to move the guitar pickup to a balanced output, being a microphone. The same idea was published that 2001 patent request like this Power Amplifier Kelas A?