I've read about it in the net, and as far as I know, that decay noise comes with your machine. It seems the 18-bit DAC's are to be blamed for it. The XP-30 and 1010 seem to have the same trouble, while the XP-80 or 1080 don't. Ask your technical support, anyway. By the way, I am considering buying a XP-60 myself. Is it worth it? Is that noise too much of a problem?
Hugo