DAC for carousel cd player?

From what I can see on the web, your player has a toslink digital out.  You can connect this to the input of virtually every dac and it should be a significant improvement.  Will you hear it?  I don't know.  You would connect the toslink output on your Pioneer to the toslink input of the dac and then use a pair of interconnects to connect the dac to the preamp.  If you give your budget, you will soon have enough recommendations to make your head spin. 

Wow, great thank you so much for responding and explaining chayro!

Hadn't thought about budget as I wasn't even sure if this made sense to do and if it was even possible...That said I guess I'd like to keep it under 1K if possible?

Thank you again for taking the time to respond:)

Get a Topping DAC for $300. Excellent SQ! Why spend more?

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. 

Does the Pioneer have a coax RCA digital output? If so I recommend using that instead of the toslink (plastic) optical output. The best optical digital outputs are glass fiber. Toslink falls short! A 75 ohm 1.5 meter RCA cable will sound much better than a toslink!

Thank you @soix and @jasonbourne52!

I will have to use the toslink to connect the dac to my cd player. I have it narrowed down to the Schiit Modius and the Cambridge Audio DacMagic 100...Can't thank you all enough for your advice and recommendations! Big help, which unit do you think?

I agree that a new inexpensive DAC would make for an improvement. Might look for a used one having the characters soix recommends.  MHDT DACs have this, having a a tube output buffer. Known to be very smooth sounding DACs. 

a used MHDT Istanbul is on sale at audiomart, R2R, tubed great sounding DAC  600.00

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. 

Thank you @soix  great advice. Kinda sucks as the Modius is out of stock right now, but worth the wait I guess. Think I'll take your advice and go that route...Thank you again for all the advice my friend, sincerely appreciated!

Yes soix made a good point. I have (had) several of the entry level Schiit products and found them to be very competent at their price point.  Have not explored the Modius however.