Warm sounding power cord for for CD player to suppress digital glare on vocals.

I feel your pain.  Sadly my solution is I've stopped listening to poorly mastered CDs and have found enough well recorded music that I can live with it.  Anything I did to make inferior recordings sound better had negative consequences on better recordings that I couldn't accept.  If I listened to a lot of older red book CDs I'd seriously consider switching to vinyl.  Best of luck. 

Harry Pierson had an interesting observation years ago. He said that if you really wanted to enjoy digital, stop listening to your records. 

Here's a  move that will bring your CD playback up to a point where it's  really worthwhile ... replace all of the fuses in your electronics (and speakers (if applicable) with the SR Red fuses. I'm in awe over the major improvement in my CD playback with these little critters. 

Oregon, whether exotic fuses influence the sound really depends on the circuit design. In some circuits, it can make a substantial difference (eg: Ayon), in others; none (eg: Vitus), so you need to do your homework & talk to the manufacturer before laying down your hard earned quan.

Forget the power cable,put a Tube Buffer between components.You will never hear digital the same again & you will love it!

Wouldn't it be easier to just buy another CD player?