When I turn the volume on both channels down and turn the reverb all the way up and shake the amp I can hear the reverb making crashing noises.V3(12at7) was lighting up like a christmas tree and very hot. I tried a second tube (12at7) and it also got hot. then I put in a 12ax7 in and now the tube is running it seems the proper temp. Is the noise normal?Is it ok to use a 12ax7 in place of a 12at7? The reverb works but like I said when I turn the volume down and I move the amp I still hear a crashing noise,not real loud but still there.I would really appreciate any input because I am really stumped. Thank you. something I didn't bring up, when I fully unplug the reverb tank the noise goes away,except there is still a slight hiss.