From the tube page linked I read: "6922 (E88CC) is an optional tube in all Decware amplifiers that use 6N1P." I have not had an earlier Taboo but am pretty sure that the change to 6922 was part of the Taboo MkIII redesign. In looking at tube talk in Taboo parts of this forum, I recall the talk being about 12 type tubes (12- AU7, AT7, AX7), so presumably this is the tube the earlier version was designed for. That said, I don't know if it would work with a 6N1P/6DJ8/6922 type tube or not.