The situation is this: I was testing a bunch of 12AX7s in my Peavey VB-2 to see if they're all operational (I don't own a tester and this was my only available option) and in the process, the overdrive channel became very hissy and microphonic. My immediate thought was the tube was bad, but when switching the tube the problem was still present and still the same after I put in yet another different tube. My clean channel, which I use exclusively works perfectly but I was really starting to dig my OD channel with my new tube of choice. Could all that tube rolling have disrupted something in the signal path? I always made sure the chassis was completely cooled down between carefully installing and removing the tubes, but I'm still a rookie when it comes to this kind of thing. No doubt I'll have to take it to a tech, but I'm hoping there's at least a slim chance that it's something I can fix at home and if not, I can at least learn why this came to be so I can avoid this situation in the future. Any and all input is greatly appreciated. Thanks.