Since I started this blog I have been listening to digital music from my Macintosh. Many of you have heard the results, and commented favorably (I hope you wouldn't buy my speakers if the sound of my system wasn't good!). Macs have very good built in audio circuitry, but the output is through an analogue stereo mini jack. The audio subsystem is powered by the same power supply as the rest of the machine, and I've been sure that there had to be better ways of getting audio into my sound system.
Well, I've taken the first step! I bought an inexpensive USB interface/DAC from Edirol (a subsidiary of Roland). It's a little breakout box, with USB cable attached. The usb cable plugs into my Mac, and I have high quality (but not braided virgin platinum handmade super cables!) cables from the RCA out on the DAC to the auxiliary in on my amp.
So far, the results are subtle but apparent. The music emerges from a quieter background, and I think I hear more detail. There are three different sampling rates available, and I will experiment further, but so far so good.