Most DVD players make TERRIBLE CD players! Why? Because the angle and focal length required for the laser to read a DVD is different than a CD. The best multi-format players (even a discontinued model like an Arcam DV-78 or DV-88) have either two lasers, or a special laser that changes according to format. DVD players are also not designed to natively play back a CD at 16/44.1, thus there is some converting taking place; and with that conversion comes read errors, error correction, and associated jitter. A player like the DV-78/88 mentioned above is designed to play back both CDs and DVDs in a high quality fashion.
A good CD player is still going to be superior for playing back CDs, in my opinion, than a good multi-format, so-called Universal player unless it is VERY good, like an Arcam DV-137/139 or Esoteric UX-1/UX-3/DV-50.