short in a tube-what happens?

A tube can short when heater wires within the tube deform under high heat and touch the cathode. Excessive heating happens when air leaks in the tube. With a heater to cathode short, excessive current can destroy an amp output transformer unless the mains are fused.

Some tubes will light up a 'shorts' light on some testers, even when there is no short.

A short is two elements touching that should not be doing so.

-Ed

Here is my experience. I was getting a kind of popping/rumpling sound coming from one of my speakers. It was intermittent, not extremely loud, but with no music playing it was very noticeable. Could not figure it out but ultimately traced it back to one of my mono blocks which was brand new. I started by testing the “6DJ8” driver tubes and sure enough one of the sides of one of the tubes registered a short. I replaced both tubes and the amp is now dead silent.