I believe the c542 and the music hall cd-25 use the same op amps, bb 2134. They also use the same d/a converter, bb 24/96. I know the nad does hdcd, I do not know about the music hall.. There are several sites which mod the music hall, so this may factor in your decision as upgradability is available.. I personally am intrigued with the jolida ja-100, but that is another story...