Interested in hearing about tube rolling experiences with the Orchid and other MHDT dacs, namely, the specific comparative sonic characteristics of the various 396a, 5670 and other compatible tubes used in the output buffer. My only experience is with the WE396a that Linear Tube Audio installed in my new Orchid.
Ok, interesting information. I have tried many different flavors of 5670 tube, some obviosly better than others, however, I will never go back to that tube after adapting the socket to emply the 6922. What a glorious difference that made in every respect compared to the stock tubes.
But not just any 6922. The early Siemens is sublime.
Best 5670 to 6922 tube adapter is made by Garage 1217 (  Superior to every other adapter that I have seen. However, please note: the pin holes are tight and therefore the tube pins must be straight in order to facilitate placement.