I used the M1 as a pre-amp feeding Master 2 mono blocks into my PSB Synchrony 1 speakers. I then replaced it with a M9. I have not compared it with any other pre-amps but I am pretty happy with the sound. dead silent, black background & lots of detail.
Isin't the Precesion 2 an intergrated amp ? So you were pre-amping a pre-amp ? That might be the reason for the hum..