Massdrop Grace SDAC, Topping D30, Schiit Modi 3, Khadas Tone Board (can be used bare, but would advise using a case). All are excellent and are <$150.
EDIT, seeing as your CD player pliekly only has digital coax or Toslink, then scratch off the Grace DAC, as it’s USB only.
EDIT, seeing as your CD player pliekly only has digital coax or Toslink, then scratch off the Grace DAC, as it’s USB only.