I though it was "perfect", but then I stuck the CD in the CD-player and played the MP3s back on the MP3 player, through the same Onkyo amp.

Careful with making that kind of a judgement. The audio output stage of any digital audio device will have different tonal colorations, even if they both reproduce the music faithfully. Even two different brands of CD player will have different EQ responses. The Rio Receiver might simply need a little EQing before it sounds the same as your CD player.

Then again, based on what you said in another thread, you're using MusicMatch at 128, so I could see how you'd lose a little quality that way.

You might want to try LAME at its higher quality settings and do some comparisons of that encoder versus MusicMatch.

You'll want a bigger hard disk, though... higher quality means bigger file sizes.

___________
Tony Fabris