Better cd SQ

Hi All,

I am considering purchasing an external DAC to use with my Marantz CD6006, trying to squeeze all the SQ from my cd's that I can. I like the sound of the CD6006, but feel like there is something better. Good idea or bad? If good, being that I know very little about DAC's, what DAC would you recommend for better SQ. My primary
Source is LP's. But I play a lot of CD's also.

All help would be very much appreciated.

Thank you,
nic919