While not often found on the used market under $500.00, the Cambridge Audio 840C is a wonderful player and DAC that sometimes pops up under $600.00.
With that said, you can get a refurbished NAD C546BEE for under $400.00. I own a NAD C542 player that is the most dynamic and detailed CD player I have ever had the pleasure to hear under $500.00 new.
http://www.spearitsound.com/CD_SACD_Players-NAD_C_546Bee_Refurbished.html
Or you may want to check out this used NAD C565BEE player/DAC.
http://app.audiogon.com/listings/cd-sacd-players-nad-compact-disc-cd-player-c-565bee-mint-2014-01-27-digital-98296-snohomish-wa
Bill
With that said, you can get a refurbished NAD C546BEE for under $400.00. I own a NAD C542 player that is the most dynamic and detailed CD player I have ever had the pleasure to hear under $500.00 new.
http://www.spearitsound.com/CD_SACD_Players-NAD_C_546Bee_Refurbished.html
Or you may want to check out this used NAD C565BEE player/DAC.
http://app.audiogon.com/listings/cd-sacd-players-nad-compact-disc-cd-player-c-565bee-mint-2014-01-27-digital-98296-snohomish-wa
Bill