Hi-Rez file playback advice please - not NDX!

Hi.

I recently replaced my ageing amplification (NAP90/NAC92) with a NAC202/NAP200/non-Naim PSU. Quite a change! This new gear has revealed to me hitherto unnoticed differences between digital music files of different resolutions and in files played via various sources and connections through my Rega DAC.

I am now reasonably convinced about the worth of beginning to collect hi res downloads from Naim, Linn etc but am looking for a good playback solution which doesn't involve me shelling out 3000 quid for the NDX - my recent purchases have already strained wifely relationships.

I have, up to now, been very happy playing normal res files back through a Sonos Connect via the Rega DAC but I think the optical out or USB of my mac book pro renders the same files sounding better. Using the macbook pro is a little aesthetically unappealing and none of these solutions will provide me with easily controllable playback of 24bit/192KHz files though so I was hoping to use the USB out of my Synology 1511 NAS (used for storing iTunes library and FLAC files) for playback. It has a reasonably useful iPhone and iPad remote control for its audio station.  Unfortunately the Rega DAC USB input doesn't accept hi res files so I would need to convert to S/PDIF. All very convoluted.

Does anyone have any ideas for a suitable USB to S/PDIF converter for hi res files into my DAC or any other easy to control solution?

I had wondered about the Audiophilleo device. Any experience? 

Thanks

J