I've mostly been using my Fubar III DAC to connect my MBP to an older analog-only stereo amp, which means I probably never heard any issues with the DAC because the amp itself has a "nice" hum that ...

I have two seperate power amplifiers with 3 prong chords. When I connect the amp to the speakers I hear a noticable hum/buzz that comes through although when I play music at low volumes, its not ...