I've found this to be true for my Harman Kardon cd player also. I'm burning in a Marantz sa-7s1 super-audio player for a friend (I DO feel lucky!) and I can't discern a difference yet,but It's quite possible that something else in my system is not up to the resolution level required to make a determination here.
For crying out loud
If you have the option, and you haven't done so, try turning off the display's on your digital gear. I know that I tried this years ago and, discerning no difference, concluded that this was just one of those anal audio things. Well, my system has evolved since then and I accidentally turned off the display on my Modwright Sony. I am now realizing improved definition and detail, voices are more natural, instruments have a more realistic timbre, images are better defined, and everything emerges from a blacker background. I really feel like a nincompoop. Here I am rolling tubes, shifting footers and stuff, and all along, a significant improvement was a push of the button away.