Chakster- Some years back; I was building a driver board for an amp(ST70) and required three 12AT7 family valves. Desiring the most transparent available; I sought the Tele ECC801S and Tube Museum was offering them. This purchase was, and remains, the only time I've been stuck with(very obviously) counterfeited tubes(out of multiple scores of deals). I'd be interested to know whether those that you bought from them have the embossed Telefunken diamond, at the base of the tube(inside the pins). If you still have them, could you take a look?