The problem with the rca/xrl's typically is that you are using them in a pinch, with a "foreign" bit if equipment, and you run the risk of having a problem. Balanced to unbalanced converter boxes these days are cheap, and offer a much better level of "insurance". In my experience you are far better never plugging in any unbalanced device into your system,
http://www.partsexpress.com/pe/showd...number=245-868
Sharyn