For that, I've been using an Alan Maher Designs Tricell Platform. It's an isolation platform that reduces noise - just put the component on it and plug the platform in. Doesn't draw any wattage from the wall, it only connects to ground. After 3 days it starts to sound really good, but you get the most out of it after 30 days. If you like the sound, try another platform on top of your CDP (on soft feet) and then place another component above on the top platform...you'll be reducing even more noise in your CDP and I think your jaw may drop all over again :)
Alan's web store is not quite ready yet, but you can get the Tricell at Amazon for the time being. One thing I like about Alan is he's up front about his noise spec. He tells you the amount of reduction AND how that curve behaves across the frequency range...(dunno who else is doing that, usually you have to guess). For the Tricell: 65db noise reduction evenly at all points between DC and 10ghz.
Probably not best to rest the platform directly on a flat surface. Some appropriately soft feet underneath should remove the slight midrange "grit" to the sound and your done.
You can also try the platform underneath a power conditioner to really turbocharge its performance.
