Recommendations for used CD player


I'm looking to improve my sound by adding a CD player to my system.  I'm currently now just using a Yamaha DVD player along with a Yamaha Aventage home theater receiver (which uses ESS Technology ES9006 SABRE DACs).  I use the receiver as a pre/pro with a Threshold S500/II amp and B&W 802 Series 2 speakers.

Right now I really like my sound and I've read these DACs are fairly high quality, but wasn't sure if I could get improved sound by adding a used, higher end CD player and possibly outboard DAC.

No SACD needed, my budget is about $400-500.

Thanks.

dastro
I should add that I also got back into audio, putting together a new system once retired. 
Yes, keep us posted. Always nice to hear feedback, once suggestions offered.
The Teac UD-501 is, IMHO, the best (used) bang-for-your-buck DAC under $500 right now.

Here’s one on USAudioMart for $375: http://www.usaudiomart.com/details/649325716-teac-ud501-dac/ (no affiliation).

I own one and it’s a stellar performer! It replaced a Schiit Bifrost.
After lots of listening and speaker positioning, I have decided to go back to my 802 Series 2 and I no longer feel the need to try to change my system to change my speakers' sound. 

They just sound more balanced and natural.  Also, they just aren't nearly as revealing as the 801s.  Which to me, is a good thing.  I enjoy all my music much more with the 802s.  Music ripped into itunes nearly 10 years ago running through an inexpensive Audioengine DAC sounds wonderful.  The 801s let you know the source can be better.