I you want to experiment with something newer or different, do the DAC route as others have suggested. That is where most of the difference will come from.
Outdated CD player
After 15 or so years of not listening to my system I am now getting back into it. Made some big changes to my analog section and now I am evaluating my digital front end. I have a MacIntosh MCD 7007 that I bought new in 1990. I never remember it giving me an ounce of trouble and sounds OK to me. My question is, never listening to any other player, am I missing all the latest technologies? Will a newer unit make a big difference in sound? I was informed back when I bought it that this unit was built like a tank. Any suggestions? If a new unit is suggested, what would be recommended in the $1000.00 range, used?