Thanks to all who have provided insight with this question. The Mac literature actually minimizes the importance of balanced except for long runs.
balanced cables
What exactly do balanced cables do, and is there any difference in sound quality? What is it that gets "balanced"? I'm in the process of buying a new(used) Mac amp and preamp, and the literature says they accept balanced cables. Is this to connect the two pieces? I'd really appreciate having some light shed on this question. Thanks.