Amp failure update:
Yesterday I received an octet of brand new NOS/NIB TungSol 5881 tubes (60s vintage). Trembling with fear, I inserted them in proper positions and listened for a couple of hours. Even in half an hour, the sound was fantastic. I switched the amp off without a problem.
Today in the morning I switched the amp again and very soon heard some noise (cracking sound) from the left speaker. Switched the amp off, let the tubes cool down and swapped the output tubes from left to right and vise versa (exchanged the channels). The problem did not appear again. Went to work. Will resume the listening in the evening. What could have caused the cracking sound? Gas burning inside the tube(s)?
Yesterday I received an octet of brand new NOS/NIB TungSol 5881 tubes (60s vintage). Trembling with fear, I inserted them in proper positions and listened for a couple of hours. Even in half an hour, the sound was fantastic. I switched the amp off without a problem.
Today in the morning I switched the amp again and very soon heard some noise (cracking sound) from the left speaker. Switched the amp off, let the tubes cool down and swapped the output tubes from left to right and vise versa (exchanged the channels). The problem did not appear again. Went to work. Will resume the listening in the evening. What could have caused the cracking sound? Gas burning inside the tube(s)?