Network player/streamer to feed NAD M51 DAC

I have a NAD M51 and looking for a network player/streamer to feed into it.  I want to play FLACs from a NAS and control it with an android app. I was initially planning to get a used UltraRendu but found out the MicroRendu and UltraRendu don't work with the M51:  Is there any other streamer that can match up with the UltraRendu's sound quality in the <$1000 price range?  I dont need wireless - wired RJ45 connection is ok.
I have a Bluesound Vault 2i connected to my M51.... sounds great.  You should check out the Node 2I if you don't need CD ripping capabilities.
Since I have an external DAC is there any sound quality difference for me between Node 2 and 2i?
I think there is an improvement ,   I think overall the Node dac is pretty decent.  
I believe the same DAC is used in both units.  Blutooth is improvement is one of the major differences
Check the streamer offerings from Onkyo, Marantz, Denon, Yamaha, Pioneer etc; they all have models in your price range.
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Elac Discovery is in your price range, not sure if it has a DAC 
Maybe the older Auralic Aries -- it has AES out which is best for the M51