Power cord to add ease and tame treble.

Sounds more like an AC issue. What do you have the system plugged into and how is the AC delivered to you system? I will be experimenting with some AC noise products that come off my fuse box prior to the AC coming to my dedicated AC lines and Porter outlets. At my friends home, fixing the AC took away the harshness in his system. Don't buy a power cord until you have fix the AC. There have been several posts about this subject and excellent comments from Sean, Psychicanimal and Lak. Look up their posts on this subject. I was chasing the same issues you were but this makes more sense before you spend money in another direction.

Happy Listening.

I second the Harmonix Studio Master

Two cords that help with removing treble harshness are Wolff's Carbon Cord and the Ridge Street Power Cords. Both are excellent and worth a try.

If you ask the wrong question you're bound to get the right answer for the wrong problem. Your problem is not the power cord...

Something else to consider looking at your system is that every review I've read about the Ayre CX7 stresses that it that it sounds dramatically better through the balanced outputs to the extent that it's been suggested that one not purchase the player unless intending to use it in balanced mode. Now from what I know of the Hovland pre it's single ended only, so you may have a mismatch right there. Remember it's not just the best components, it's their synergy together. Perhaps you could borrrow a balanced preamp or a different cd player and see how things sound. I'd recommend against using the band-aid approach of a power cord until you look at this issue as well as room treatments and ac issues. Good luck!