The Lumin U1 mini brings very clearly the most SQ improvement. The stereo image becomes wider, with better positioning of the sound stage and a more laid back presentation, against a complete black background. It’s like the sound is reprocessed and becomes de-digitalized. The SOtM tx-USBultra also “de-digitalizes” the USB signal, but not to the same extend as the Lumin does.
I preferred the AES/EBU output (Love Cable) most, just over the coaxial BNC connection (Nordost), and least liked the USB signal path. Maybe it’s the Devialet USB input that’s not the best input choise. I’ve compared between Audioquest Diamond USB cable (100% silver) and the AQ Carbon USB cable; where the AQ Carbon sounded less harsh(d) that the Diamond. But I think that silver cables are not the ideal match with Devialet Expert 400 (class-D).
The A/B comparison with Chromecast was not yet done (will do in the near future).
Budget network cables were replaced by AQ CAT700 UTP cable with Telegartner connectors.
Standard power adapter of the network switch was replaced by lineair power supply.
SBooster adapterkit for Lumin U1 mini has been ordered, and will be delivered next week(s), in order to feed the Lumin with SBooster power juice…