[poulsbobill]

It's been a few days and the "blurp" has gone away, but while i was spending time in the back of the set i noticed this.
This is one of the 6b4g power tubes, they were purchased as NOS set about 2 months ago. You are looking at the right tube and the left one is in the frame.  I know it is dark but i wanted to capture this blue/purple glow.  It is about this bright with normal ambient light.

What is happening?  I switched the tubes and the glow follows the tube and not the circuit.  I have 2 heater circuits one with about 6.1 volts and one with about 6.6. You can see at the end of the vid that a small area stays blue once the tube warms up, but  it is not evident in the other tube.

I use a fake name for youtube.

Thanks

Bill

 [Video: https://youtu.be/llSyscjRO4A]