The Ming Da amp came with a set of Sovtek 12AX7 (7025) tubes, but since I already rolled the driver tubes to Sylvania's I thought I would try a set of NOS Sylvania long plate 7025's.
Tubes are almost exactly the same gain, quite, and no microphonics that I can tell. I'm reserving my decision on the difference in sound quality until I can get a few hours on these tubes. So far so good!