Andrew, only if your Roon Core is Digital Signal Processing the bit stream, or if the Server is less than optimal, like an underpowered CPU/RAM, then you can expect to hear a difference vs. Mosaic.
Otherwise, when both Roon Core and Mosaic’s UPnP Servers are running optimally, there will be no difference between Roon vs. Mosaic playback as both are able to deliver bit-perfect synchronised bit streams to the dCS DAC. dCS’ own post on this question is worth revisiting if you haven’t already ;
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