You're best equipped to answer your question...
How did you rip them? iTunes has several different combinations of formats, Apple Lossless, AAC, AIFF, MP3, and WAV. On top of that it has options for bit rates of 64K through 320kbps.
You can maybe find out how you've ripped them by going to Edit>Preferences>Import Settings on Windows and Preferences on a Mac and check the settings. If you've been using the default settings, you've no doubt lower resolution than the CD.
How did you rip them? iTunes has several different combinations of formats, Apple Lossless, AAC, AIFF, MP3, and WAV. On top of that it has options for bit rates of 64K through 320kbps.
You can maybe find out how you've ripped them by going to Edit>Preferences>Import Settings on Windows and Preferences on a Mac and check the settings. If you've been using the default settings, you've no doubt lower resolution than the CD.