DAC Suggestions for Aurender N100C

Suggestions for DACs that match well with the Aurender N100C (basic N100 with coaxial option).  I have mine matched up with a Schiit Audio Gumby.  The overall sound is good, though there is often a graininess that is an issue.  I exchanged my first Aurender (thanks Music Direct), but the problem persists.  I've used USB and Coaxial.  Now I'm wondering if it is the synergy (or lack there of) with the Gumby.  
@mgrif104 I have compared the Aurender N100 to a Lumin U1 and the Lumin was superior. Perhaps you meant the Lumin U1MINI? If not perhaps you should upgrade your DAC or USB cable.
I have a PS Audio Direcstream DAC.  Excellent DAC and very good discounts can be had for a new one (~40%]
Sfseay - it was the Lumin U1 Mini.  My bad.  In that comparison, the Aurender had clearly superior soundstaging.  The detail and tonal qualities were about the same.  

I’d actually like to audition the U1 as I’ve heard good things about it, but I also found the app to be inferior to Aurender’s conductor (and even the Bluesound OS to be honest). I tried to give it enough time to become acclimated. But, I would expect the full sized U1 to be better than the Aurender - as it should be at $2k more.  

I’m using an Exogal Comet with my Aurender N100H via USB with excellent results.  
Awesome feedback and some good food for thought.  The Ayre wasn't on my radar, but I have been considering the PS Audio Directstream.  I like their topology of utilizes software updates rather than needing replacement because of new chip technology.  Thanks.