Guessing on ADC = Analog to Digital Conversion?
I tried recycling two older DVD players as CDP - after my Philips CD-960 finally expired. They both would run open loop on rotational speed - perhaps trying to read the DVD. The poor CD would jump the arbor and scratch itself. My once great Yamaha DVD player, and my no-name $29 at a grocery store DVD player were discarded. I ordered an Onkyo C-7030 CDP and love it - it sounds better than a repurposed DVD or even my early Sony BRD player (analog outputs). Ultimately, I got a second C-7030 for my upstairs hobby room. My office stereo is now comprised of a C-7030 driving an Emotiva Mini-X A-100 connected To a pair of Klipsch RB-81ii's - and I love it. My hobby room has my original Sony BRD player as well as my second C-7030 as selectable inputs to my Onkyo TX-8020, so I can play CD's on both (I have a 24" LED JVC monitor fed by HDMI so I can watch movies - or select CD's easily.). The best way I can describe the BRD and DVD players playing CD's is that they sound 'hollow', when they sound full bodied from the Onkyo CDP, which reportedly uses excellent quality Wolfson DAC's. The stereo Onkyo receiver is used on Direct mode, ie, bypassing the tone controls, and drives a pair of Klipsch R15M's, with my HT's reject Polk PSW-505 subwoofer 'on call', if needed. It may have helped watching the BRD 'Director's Cut' version of "Das Boot" last week, but I generally leave it off.
Consider getting a decent dedicated CDP - they really do sound better!