What's your room like?
I have had rotel amps and have looked seriously at Adcom, and I don't know that there is much difference between the two within the line. Cables can make a big difference, but I would look at the source first. Cable merely transmit signal. Some do it better than others, but if you have harshness like you mention, it's more likely to be the Denon. Sorry!
Better cables might tame some of the harshness that is introduced by the cables, but better cables could sound even more harsh if the issue is the Denon. Borrow a CDP from a friend and see how much difference it makes. Less expensive gear is built around compromises, the ones you hear might be part of the design inadequecies of your gear, or the cables. It's difficult to point out the source of the problem without actually swapping things in and out.
Did not know about the home demo option for cables. The room is big (24 by 28). Sounded just as bad in a room half that size. As far as the source is concerned, I hear the same level of harshness whether it is the cable box or cd player. Based on what you guys have said, I suspect it is the cables. For my modest system what should I pay for a decent pair of six foot rca cables? I suppose there is a point of diminishing return. Thanks for all of your help.
I had an Adcom preamp and Adcom amp (7500 also) combination before. I switched to a Sunfire preamp and Sunfire amp combination. I'm happier with the Sunfire vice the Adcom. The Adcom seemed to lack in overall strength/authority (amp) and my system sounded thin. The Sunfire is definately warmer and stronger sounding.
My speakers were and still are Klipsch Legends (horns) so they tend to be on the bright side. To get the mids and highs under control (at least for my system), NBS cables were the miracle answer. The mids were transformed and the highs were much more tolerable.
As others have noted, the source is important. I just switched from a modified Music Hall CD-25 to an EAD cdp. The sound again improved becoming smoother and much, much more analog sounding.
IMHO, NBS cables and the source would be a great start for you.
Problem solved! First and foremost, thanks to all who helped. A new amp was the answer. I went from 150 by 5 to 300 by 5. Both Adcom. I still have the same cheap IC cables and cheap Denon 2910. I have a new Denon 3910 on the way. I would not have bought it if I knew what a difference this amp would make. New cables are coming too. I cannot possibly imagine this system sounding any better than it does now. I am embarrassed to say that I think the harshness I was hearing was the amp clipping! Someone at usedcables.com told me about the clipping possibility and suggested I try more power before I try new cables. How's that for honesty? I am sure there are those who responded to my questions that thought about clipping. Probably assumed I would know clipping when I heard it. Thank you for that assumption....but.....like I said....I am new at this! Vman71 and Fife nailed it with their responses. Thanks, man! By the way, my closest neighbor is 1/4 mile away. He commented that he likes my new Tracy Chapman CD. What do you suppose he was trying to say?