Second and just as important, get some good interconnect cables. Those RadShack cables are definitely limiting what the Cambridge can do. (And they masks the limits of an older CD player). Good interconnects through your whole system will work wonders everywhere. Nordost Solar Wind and Blue Heaven are good choices. Kimber PBJ are liked by many, but I find they smear some CD players sound, but can be used elsewhere successfully. Also check out Bettercables.com for good cables relatively cheap. And those new ZuCable Oxyfuel work well (www.zucable.com).
Your new preamp is a good idea too!!! Do you use a power center? The Monster HTS2000 is a good place to start.
Now you see why all of us audiogon members are slowly going nuts. Welcome to the club.