if the system does not have RCA connections it probably isn't the best anyway.

Actually, it's a fairly decent system (for a bookshelf), it's just a little old. I've certainly seen much, much worse systems that *do* have RCA aux in connections, and I've also seen some newer fairly expensive systems that also don't have aux in connections. I got this system before mini-disc players, iPods, and what-have-you were invented, but long after vynal went the way of the dodo, so there was much less need for aux in.