DAC For Krell KAV300CD Player

Would it behoove me to add a DAC to my Krell KAV300CD player? It has a toslink digital out & all that I can find on it digitally wise is that it's a 20 bit DAC onboard.
Another concern would be to upgrade to a player with a wider freq. response to match my speakers & electronics, below 20Hz. 16 HZ & 5Hz respectively. As I'm getting older, I know the hearing tends to go, but I can still feel (like in a cathedral) which is all a part of the experience. Any ideas?
If you want to sell your player I may be interested. That player is best a transport and not the DAC. With that being said adding a DAC would be stellar. You pick the DAC.