What would cause the 6SN7 tubes to do this?
I had been using a pair of Sophia Electric Grade A 6SN7 for about a year and a half. A few months back, I switched in some NOS tubes just for a change. And then yesterday, I decided to pop in the Sophia Electrics again. When I put in the Sophias, I swapped the Left-Right positions of the tubes from the last time they were removed, as I often do. When I powered everything on, there was a great deal of noise coming out the speakers. Not just tube rush, but real hiss and white noise. Swapping the positions of the Sophias back to how they were originally the last time I removed them quieted them down to where I am only hearing tube rush (although the tube rush is noticeably louder than what I hear from some of the other tubes, including the NOS tubes and the stock tubes that come with the LS100). I've tried swapping positions Left-Right and back several time with the same result.
What is this? Is one 'side' of one tube bad?
