Issue with Graininess from my Aurender N100H

I've been using an Aurender N100H for the past 3 months for digital streaming (TIdal HiFi) and my digital library (AIFF, ALAC, Hi-Res files on the internal SSD drive).  Overall, the sound is outstanding with good soundstage, serious detail, rich timbre, etc.  However, much of the music has a "coating" of graininess or static.  When the system is not playing a track it is silent, but during songs, especially, quieter passages, the static is more pronounced.  It happens on both the internal drive tracks and streaming via ethernet.  It seems to be more pronounced while listening to horns - alto and tenor sax and trumpets.

I have tweaked the system by switching out the stock power cable with a Shunyata cable plugged directly into the wall versus the Venom.  I have run the Curious USB cable directly to my Multi-bit Gumby and also through an ISO Regen with an Ultracap LPS-1.  I just picked up a Schiit Eitr SP/DIF converter and have a Kimbler D-60 going to the optical.  In each case, I get the same graininess.

Anyone have a similar issue.  Remedies?  Thanks.
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Do you have another source to make sure the issue is not the Aurender? Perhaps it could a noise issue be further down the chain, any tubes anywhere?
When I had an Aurender N100H, I heard the same grain and static.  I switched to a Sony music server and have never been happier.
Interesting, stereo5.  You and I may be the only ones with Aurender issues as most users seem satisfied with the sound.  Jon, I play vinyl on my system and it sounds perfect.  It is definitely isolated to the digital signal and it didn't do it when I had a W4S modded Sonos connect in the signal path or a Marantz CD player.  My records through a Music Hall 5.1 sound fine.  It is definitely an issue with the Aurender.
Understood guys and what an odd problem for a streaming device. Has either of you contacted Aurender? Self noise in a component like that should be way below the threshold of the rest of your systems.
Based on your description, it seems the graininess and static is only on streaming digital  My suggestions are:

I suggest you turn your router and modem off for 2 minutes by removing their plugs from the wall.  Remove the battery, if any, from these devices.

I suggest you call Aurender Customer Support and ask their advise.   My Aurender N10 has no graininess, and, it seems, many other do not either.  Your unit might have a problem.

Is it possible to return the unit to your retailer and have them test it in their system?   As JOND suggested above, can you try another digital source to see what happens. 

Is your router and modem working okay?  My Linksys router was dropping packets and this was messing up the signal.   I doubt this is the issue but it is worth a try.

JOND above suggested your check your other down stream components.  As I understand it, your CD's play okay so this means there is a problem in the digital area.

My best guess is there might be an issue with your Aurender that needs repair.   Did you buy it new or used?   I still think your best option is to return it to your retailer for his testing and also call Aurender Customer Support for help.  Please keep us posted.

I also suggest the following:

Power down your Aurender N100h for 2 minutes and re-start (power down on Conductor iPad).   This process might take several minutes.  Its cache may need to be cleared.

Please check all your electrical plugs and cables to ensure they are correctly plugged in.   Unplug ALL your cables and plug back in.

Please review the settings on your Aurender to ensure they are set right (they probably are but it is worth checking)

Please check your USB cable to ensure it is okay.  If possible, borrow another USB cable test.   Please keep us posted.  

@pg62, I forgot something.  

Please ensure your software on your Aurender N100H and Conductor App are current. Aurender updated the Conductor App on December 29.    See:

i do not know if the above will fix your graininess issue but your software needs to be current.  As I said above, please call Aurender Customer Support and Please keep us posted. 
hgeifman, thank you so much for all the advice on this issue.  I am working on your list.  Aurender support asked me to connect to one of the USB data ports underneath the ethernet connection.  I did that and the graininess has stopped.  That said, the sound is a bit more digital, but I just made the reconnection and perhaps the port needs to burn in.  I may return the unit and seek a repair to the main USB output port which seems to be the culprit.  I bought it new through Music Direct.  I'll keep you posted.
Music Direct was good enough to take back the defective unit.  I replaced it with a N100C, the latest N100 with a coax digital connection.  I set it up yesterday and it sounded great.  I may try the USB rig I'd gotten - ISO Regen and Curious cables, but I'd doubt they'd sound better than the Kimber Kable D-60, but you never know.

The best sounding S/PDIF cable for the money:

Steve N.

Empirical Audio