Mechans invited me to take a look at this thread :)
Regarding the "Western Electric 6SN7GT," here's a short history lesson. Western Electric, as we all know, is one of the great American tube manufacturers. The interesting factoid that few people know is that WE opened up a low-key operation in the UK in the late 1800s, which was then bought out by the International Telephone and Telegraph Company (ITT), which then became a company some you guys may recognize: Standard Telephone and Cables, AKA STC. STC transitioned to various brand names - the one most people know is Brimar.
Looking at the tube, it looks like a classic UK tube (similar to Tungsram and Brimar). WE probably continued to do limited business in Europe for decades so it's not surprising to see them rebrand a STC tube, whose heritage is Western Electric.
Edited by Len - 2/15/14 at 7:56pm