Sound format question....

Since stepping up to a pretty good Reference grade Audiophile set up (Set up and configured for music only) There's been only one downside... My ears have become fine tuned enough to immediately notice the difference in sound format. So much to the point where I don't like even the best MP3 music. It's so noticeably lacking in range, depth, and feel. Question? Like many, regardless of wide variance in sound I do like Pandora, but why is it that from random song to song on Pandora I am hearing "ok that track sounds pretty good" or "Why does this Pandora track sound like ultra compressed garbage? It's about 50/50 and regardless of new or old song will vary so much in terms of sound quality.

Could this be an issue with my sound source? I'm using an Oppo BDP-105 and piped in Analog. No digital.