The iTunes may be mp3 format. If so, they have lost some quality, mostly in the high frequencies. You may not notice much. The mp3 format is a compressed wav file. Data is lost in this compression.
The EAC that bigkidz mentioned is for extracting wav files from a CD. In the extracting, or ripping, the cdrom reader does not always do a perfect job. The EAC software does the best job of correcting this.