Well. My extremely unscientific findings are that the vintage 6V6GT's sound better than the KT-150's. I bought a pair of Sylvania 6V6GT's on eBay (cheap, like $40 incl. shipping from Canada) and they just sound so much smoother to my ears/system than the KT-150's. I feel like the 6V6's sand off the round edges and it sounds more musical than the new Russian tubes.
I thought these were kinda cool because they don't have the usual gray/black inner layer on the glass. Just the chrome-dome getter. I like 'em. They'll be a great back up set if I don't *LOVE* my vintage TungSol 6550's that are en route! Hard to fault what the 6V6's do in the Inspire amps, for sure. Such a pleasure to listen to.
