I'm no techie, but a true digital cable is supposed to have a uniform impedance of 75ohms from tip to tip. Few, if any cables actually achieve this spec, which probably accounts for the wide variation in sound and opinions as to whether this matters or not. Some analog interconnects, when used as a digital cable, may brighten or darken the sound and can negatively affect the soundstage. If you want to play it safe and minimize your investment, you can get a half way decent canare digital cable for around $20 on Ebay.
