Thanks to all for the help so far. After thinking, it seems it will be more feasible for me to replace my source first and the amp after. I think I want to look at the cambridge 540 and 640 models, if I eventually go with either the NAD 320 or cambridge 540 amp, will I hear a difference between those 2 cd players? Just trying to determine if it is worth it to spend the extra $ for the 640. Thanks.