Agree with Rodman. I just lost a bias resister because a tube went bad. Fortunately, the factory arranged for same day service at my home, all under warranty. When trying out the socket with a back up tube, one of the back up tubes also had a rattling sound. Both tubes went back to the vendor for replacement. Trust me, you don't want to use the amp as a tube tester.
Further, no one can diagnose a tube problem without seeing the suspect tube, and even if the tube is directly examined, I still wonder. Good luck.
Further, no one can diagnose a tube problem without seeing the suspect tube, and even if the tube is directly examined, I still wonder. Good luck.