As you mentioned, I'm completely stocked up on new Tung Sol 6SN7GTB tubes, so logic (and my wife) would tell you I should be good to go for life, right??? . . . . Nope, similar to you, I've already purchased a matched pair of NOS GE 6SN7GTB tubes just to see if they'll "improve" the sound signature just a little bit more.

They haven't arrived yet (expecting this weekend), but I'm excited to start rolling different tubes into the differential gain stage. I've also heard good things about the new production Psvane CV181-T MKII (6SN7) tubes, but can't bring myself to shell out $172 for a pair. I'm assuming you're happy with sound of your NOS GE 6SN7GTB tubes?