newbie DAC question

Wherever you heard that the differences between dacs and interconnects would be "HUGE"...you should stop going there.  They've been telling you tales of Bigfoot and the Loch Ness Monster. 

The limiting factor in your case (setting aside the room, which may be perfect for your setup, we don't know) is your speakers.  There's nothing wrong with Elac speakers - they're great for the money.  But at the end of the day, they're $300 speakers.   I'm not saying they're bad speakers, not in the least, but encouraging you to swap dacs, or upgrade your interconnects, or playing with coax vs. USB vs. whatever is barking up the wrong tree.  Doing those things may affect the system (though I doubt it, as you've discovered), but the sound will still be coming out of $300 speakers.

If you want better sound, put every dollar you can into upgrading your speakers.    And if you're emotionally attached to the Elacs, or simply can't afford to upgrade them, then forget about this thread and enjoy the music you have now.  Playing with those other things is a waste of your time and money, and frankly I'm surprised I'm the first person on this thread to even mention a speaker upgrade, though I know it's not the question you asked.

It's not just this hobby either, kremrik.  In a society, and financial system, based on consumption rather than savings, the goal is to get you to spend more and more, consume more and more, and to always be chasing the next acquisition.  This industry specifically wants you to never be happy with what you have, to always assume that spending more money will make the music sound better, and that you're always one more upgrade away from musical nirvana.  The "keeping up with the Joneses" dynamic is alive and well here, just as it is with home ownership, auto ownership, and numerous other consumer categories.   You, like each of us, have to know when to say enough is enough.