I've actually used the Rotel RSX 1065 before. Great piece by itself and an excellent preamp when paired with good amps. "Increase in sound quality at the same level of output," is the perfect way to describe the advantage of using an external amp. Smooth/ warmer midrange, crystal highs, better low end if you are running your speakers full range, and less chance of otic fatigue which plagues entry level to moderate priced (all but the best) receivers.

Mini Rock's Lounge.com