Tube or Amp Problem? Please help.

lowrider57, I am not home now but I will check. If I do I will definitely try it out. Hope I do but unfortunately I don't think so.

russ69, thanks for all of your helpful comments.

I agree.   Try a different tube.  Tubes that do that have an internal short or something that made it have a fireworks display.  
 

hopefully a new tube on that position will bias fine and sound will return as normal. 

Good advice above. If peak performance is what you are after then replace both sides. I would recommend ordering two complete sets. I always have a spare set.  While not tremendously unreliable… tubes wear out and occasionally fail. With a thousand hours on them, I would (me) swap them all out. Tubes are getting more expensive… as a hedge, having an extra set doesn’t hurt. 

Tube is probably bad and the bias from the resistors is probably also gone bad.  Check under the hood to see if you see any burn marks on any part, and have the tube tested.  

If you are close to New Jersey, I would help you take a look and evaluate the issue.

Happy Listening.

Without cross checking with other tubes, I wouldn't run the amplifier. There may be a problem with the screen voltage being out of spec (which can cause tube failure, distortion, and/or inability to increase or decrease plate current to spec). The amp will probably continue to eat tubes on that socket. 

A lot of times it is bad solder joints that causes these kinds of problems after a good amount of time of normal operation -- and simply reflowing solder joints solves the problem.