Dear sir, I have and adcom GDC 700 HDCD decoder listening to an hdcd encoded cd is like night and day compared to redbooks. The dynamics are incredible, you hear instruments and vocal inflections you never thought possible through your system. Blake Sheltons newest cd is recorded in hdcd and the sound is off the charts. Some on this forum seem to think its no big deal, but take it from me it's a big deal, look for an adcom 700, 250-300 used. You will thank me.