I'm about to purchase and start using a Nad C521-Bee in place of my DVD player,and was wondering what kind of differences i can expect.My system is lacking bass and i'm sort of hoping this change will help this problem,even if alittle.Thanks guys!

That will depend on the DVD player. If it is of any decent standard then the differences will be between very small and nil.

I am also thinking of the same upgrade. My DVD is a Denon 1930, my amp is a Sony STR-DA1200ES and my speakers are Acoustic Energy Aegis Evo 3 floor standers for stereo hi-fi. I have further Aegis 1 speakers for film surround sound use. Would I gain a noticeable benefit with cd audio with a Cambridge Azur 640CV2.

Any advice much appreciated.