TAD 6L6WGC-STR Redbase Tube Duett

The tube sockets on the TAD tubes have a little centre pin that is supposed to make sure that you can only put in tubes in one correct direction. The round piece on the bottom of the tubes and the centre pin are significantly smaller than on other tubes, like Sovetek or GT. So it's very easy to put in TADs in the wrong direction, there's no physical resistance when putting them in incorrectly.
TAD support's snotty response to this issue is that the tube sockets vary due to manufacturing variances, and that one can't expect the centre pin to actually perform it's intended function (!). (Important: I'm referring to TAD support, not Thomann support - my experience with Thomann support has always been very good..)

Soundwise, I was unimpressed by the tubes, especially compared to GT and Sovtek. The attack phase of the note almost disappears, dynamics and articulation are not great. The tubes that the TADs were supposed to replace went back in...(Fender 57 Tweed Twin RI amp).