I just started playing piano and gained interest in digital audio. My mac pro having been used mostly for digital photography so far, it only had fairly basic speakers attached (LaCie USB speakers designed by Neil Poulton). I was thinking about investiing in a small desktop amp (NuForce Icon 2, project, ... SMSL) together with a pair of good monitor or dipole surround speakers. Many such amps offer a USB connection, but I noticed that my current USB speakers often suffer from spurious emissions. Is this a Mac USB audio issue? Would a DAC connected to the digital output of the Mac Pro sound better?