Have a '95 blues deville 212 that has been played pretty hard for 20 years. Started having a problem 4 years ago where it would cut out to about 1/4 or less volume after playing loudly. I shelved it as I was using my orange ad30 for gigging anyway. About a year ago I decided to take it to a tech who replaced the tubes, cleaned some joints and gave it a clean bill of health....I had been playing it in an apartment at low volumes and it worked perfectly for the last year. Last night I decided to take it to rehearsal and crank it....about a couple minutes in I hit my OCD pedal and 30 seconds later the problem occurred again, little volume and some distortion, even when turned up to 10. I checked the tubes and one of the power tubes was out, cold and lifeless. Would this cause this problem, or are these problems separate? The amp sounded great at full power for a couple of minutes. I need to know if I can just replace the power tubes or if i need to take it to a tech....any help is appreciated.