This is fantastic, thank you very much for sharing. The R2R v3 DAC looks like a significant improvement over the v2 version in terms of design.For those who want to try an external R2R dac I higly recommend this little gem that for less than 180 dollars (version with dedicated power supply) offers an extraordinary result in terms of width and depth of the soundstage, the best I have ever heard, maintaining detail and excellent separation/identification of the instruments in space (3D positioning). An even wider and more articulated soundstage but (and) removing that sense of crowding and fatigue that characterizes the ESS, compared to which it results in a more material (full) soft and relaxed listening, but without sacrificing dynamics and detail.
Obviously both voices and acoustic instruments gain in body and naturalness, a characteristic of all R2R.
https://aliexpress.com/item/1005007859513902.html
All this... already with the stock Muse 8920, whose performance has however been significantly improved by the new configuration of the driver circuits of the V3 version, but it can then be further improved by replacing the 8920 with this new L.K.S Audio Pure Class A opamp (discrete board- external mount) that I discovered, which makes the sound even more "analog" and absolutely free from fatigue, while maintaining excellent details and separation.
https://aliexpress.com/item/1005002717436756.html
I recommend trying this also in pair on the XD05 Pro, the best result I have obtained so far; compared to the MuzgAudio it has a greater soundstage, instrument separation and even more less listening fatigue.
Funnily enough, I have a pair of the L.K.S opamps in my Ali basket so it sounds like I order them. Do they fit inside the v3 case or do you need to leave the lid off?
Thanks again for your continued research and sharing of information.