I have been fortunate enough to compare the Khadas Tone Board, Denafrips Ares II DAC, and Nagra R2R DAC ($35k) side by side installed in a $100k+ system installed in a custom designed "idealized" acoustic room. Sources were a Nagra CD player, Nagra preamp, VTL tube monoblocks, Rockport Avior speakers, Melco streamer. Various redbook CD recordings and streamed files of various resolutions. Connections were via coax for lower resolutions and USB for higher resolutions. The Khadas was powered by a linear supply of 5 volts to header pins 1 and 21 (not via USB). We used RCA outputs for all DACs. The Nagra DAC and Denafrips sounded very similar. The Khadas sounded very different. I'm not talking slight variation in sound but a LARGE variation in sound. The Khadas was more "exciting" with deeper bass drive, larger soundstage, a more forward presentation but slightly grainy in texture. The Denafrips and Nagra were more laid back and sounded more refined and smooth. The R2R dacs were superior in midbass pitch and definition most noticeable on acoustic bass and lowest piano notes. I found the Nagra DAC to be slightly superior to the Ares in refinement, but I must admit to splitting hairs and of course subject to faults of non double blind testing. At my home, I find the sound of the Khadas very similar to that of my old Oppo Blu Ray player that has been upgraded with the Burr Brown OPA1611/12 op amps, but the Khadas is a tad better for revealing ambience, reverb tails and a bit more cohesive bass response and a slightly wider soundstage. My system uses NCORE 400 amps, Pass preamp, and tall Line Array speakers. I am contemplating purchasing the Denafrips so that I can have both an R2R and DS DAC on hand. I can imagine recordings that would benefit from applying a specific DAC.