Question About Amp Hook Ups

I am currently listening to a Krell 400cx amp and using balanced cables from my preamp. I am going to audition an Edge NL-10 amp later this week and have just found out that it only takes RCA ended cables. Can anyone tell me why a manufacturer would make this choice. Is there any sonic benefit? I was under the impression that balanced cables were better than RCA ended cables, especially to the amp. But what do I know if a top company such as Edge would use RCA ended cables only.

Any advice or opinions would be most appreciated.
thanks.