I have a 66 BFDR with a C-Rex. I just put the C-Rex in a few weeks ago and have been playing the hell out of it while my DRRI is in the shop. The amp was running beautilful cleans up to around 6 1/2 before any slight breakup. All of a sudden there is a lot of breakup with the volume at 5. I notice that the power tubes and rectifier tube are loose. Can this cause the sudden change? I'm not an amp guy at all. Can I open it up and tighten the sockets withour discharging the caps?