I have a pair of SX1000. No R. And NC500 one up Nords.. The Nords sound better with no EQ or tone control. The W4S I had to give them a little bump +3-6db) on top and -3 in the lower mids. Sure are powerful amps though. They are a very black background too. Dead quiet either one. They both push small planars and ribbons all over the place..
Regards