I've had a few emails regarding this thread so I guess I need to chime in: the MP-3 is fully balanced-differential from phono input to main output. The output is patented, is direct-coupled and the preamp is zero feedback throughout. It employs a true bi-polar power supply, not unlike solid-state designs in that regard. Even the volume control is balanced, made out of a custom-built switch and made up with fixed resistors.
It was first introduced in 1997 and evolved out of the MP-1 which was the first fully-differential preamp made, so far as we know (fist introduced in 1989).
It was first introduced in 1997 and evolved out of the MP-1 which was the first fully-differential preamp made, so far as we know (fist introduced in 1989).