Agree with Zd542, the DH-75 gets good reviews, and should work well in your system. Also, digital XLR is 110 ohm and digital RCA is 75 ohm. Ive seen digital cables with XLR on one end and RCA on the other, but that just makes no sense as it would seem to result in a mismatch of impedance.
When it comes to cables, patience is a virtue. Too many people get caught up in spending more than they should, when upgrading a component makes better sense. Cables do make a difference, but sometimes its only that, different, not really an upgrade, but we think it is because the cable was more expensive. Some years ago, I rolled speaker cables on a $5000 pair of speakers, and ended up using a $400 pair, just better overall sound than a $3000 pair from a well respected company. And not just me, several audiophile friends agreed.
Zd542 makes a good recommendation to upgrade the preamp, but if you dont want to add another component, save the money, and later, just upgrade to a better integrated amp.
If you care to share, what does your system do well, and what needs improving?