Are the Sophias and the Black Treasures made by the same factory but sold under different labels? I have a pair of Sophias for my ModWright Sony SCD-XA5400ES and have thought about trying the Black Treasures but they appear to be the same tube. If these tubes are made by the same factory how do they differ?
Best 6SN7 Pre Amp tubes?
How the Shuguang Black Treasures CV181-Z (6SN7) compare with Sophia Electric 6SN7 "A" Grade tubes? Any recommendation for ModWright LS 100 pre amp?