I just want to say thanks to everyone that offered suggestions to me a few weeks ago. After the advice here, I replaced my Mac Mini with an Allo DigiOne Signature / Uptone LPS1.2. I wasn't expecting much, but it ended up being a nice surprise. I found that the noise floor was substantially lowered and the resolution/imaging got better. I didn't even bother spending a lot of time with an A/B comparison because it was such a clear improvement. I'm not sure how much of this might be due to the Adagio performing better with an SPDIF input, or if the DigiOne is a much better transport than the Mac Mini, but either way I'm happy with the end result. I'm guessing it's a combination of the two factors. Thanks again for the help!