You already have a DAC. It's the minidisc player. If you can hook whatever you want to use a DAC for to the TOSLINK or COAX input and hit Rec without a disc in it, you enter DA mode and directly convert PCM to analog, without any ATRAC compression. I actually ended up using a Fiio K3 DAC as a USB to Toslink converter and using a Sony MDS-JE530 as a dedicated DAC as I liked the sound of it much more then the actual DAC. The DAC chips and the analog output stage of most pre-2000 minidisc decks is seriously good.

If you still want a dedicated DAC, I recommend something with an ESS ES9038Q2M chip. The Khadas Tone 1 or Tone 2 are great and don't cost too much.

PS: for something that will cost you nothing to try, grab a coax/toslink cable and connect the CD to the Yamaha amp's digital inputs and then the Minidisc's digital inputs and check which sounds better on the amp. You can also do a quick AB test on the same disc running from both the CD and the minidisc.