@curiousjim the Aero dac that I had in my system had Ray Reserve tubes. Comments made in the 6 dac thread were based on whatever stock tubes shipped with the dac. I have a LTA MicroZOTL preamp and the stock tubes that shipped with it weren't very good. I suppose it's hard for LTA to keep a good inventory of NOS tubes.
I have put my system together using components that are neutral and detailed. I used to have issues with sibilance that drove me nuts. I think my preamp was the biggest issue and ironically, it was a well regarded tube preamp that I thought would add warmth (I find that warmth and sibilance are not mutually exclusive).
Anyway, I thought the Aero dac sounded excellent. The ability to tube roll adds some flexibility. I think you would like it. I'm not good at describing the sound. It just sounds real. Detailed with good separation of instruments. Big soundstage.
The Gustard R-30 dac has three filter settings. Two of the settings would tame the highs a bit. I wonder if the reviewer tried them?

