I don't know how different they sound but based on my experience AC plugs plays a big roll on sound quality. Actually, because of its cheaper price, I was going to purchase a couple of Cardas NEMA/IEC. On the ads it says copper metal connector! I called them last week and found out base metal is beryllium copper and plated with Rhodium. Furutech F-15 series (plus or even earlier version used by Cardas) use pure copper as base metal and R or G plating. Conductivity and frequency integration of pure copper is far superior than beryllium-copper.
