DAC for carousel cd player?

The DacMagic 100 was introduced in 2012 and as far as I can tell hasn’t been changed since then.  It may still sound fine, but nine years is an awful long time in the digital world, and as good as it might still be I’d put my money on a new design by Mike Moffat in the Modius.  FWIW. 

I agree a better DAC should make a nice improvement.  I’ve had a Rotel prepro and am familiar with the house sound, so I’d recommend a DAC that’s not too analytical and has a little flesh on the bone as it were or the result may be a little fatiguing.  The Schiit Modius is only $199 and offers a relatively robust sound for a cheaper DAC so may be a good fit with your Rotel and yield significant overall improvements.  Add a decent toslink cable that shouldn’t be very expensive (sorry I’ve no experience with them so no specific recommendation) and you’re good to go.  Best of luck.