I have not compared the 50 to the Ref 1 but have heard the Ref II, LS-25 MKII and BAT VK-30SE in the same system. The Ref II was better but only by a small measure, mostly slightly more natural sounding and slightly moer tube sounding (no edge). You would not know it unless you heard it in direct comparision. All of the componenets in your system have to be up to speed to hear the differences.
