I played my new '65 reissue in the store for over an hour, so I know it was fine when I bought it. When I take it off standby now, (it's about a week old) it hisses like a sonofagun. I've tried different outlets around the room without a difference. There's w-ifi in the room, if that affects anything. The amp is tilted back, but it hisses sitting flat too. I have another tube amp, a Mesa 5/50 that's absolutely silent. Is it just the nature of these things? I'm positive it didn't do this when I was doing the sea trials.