I bought some tubes from these guys and am now looking at this DAC by them. I don't know much about this DAC as there are probably only a handful of them even in Japan. (Hence no reviews) However, the company was kind enough to supply lots of different circuit diagrams and while it won't tell us exactly how the unit will sound, it will go along way into telling us how good their engineering is. I know absolutely nothing about circut diagrams but I happen to know a place where there are lots of circuit peepers.
link goes to lots of info: