Over-voltage on tube heater… any damage?

[elskardio]

Hi guys,
While testing a 6s6b tube, my psu regulator for the heater died and the tube filament received 12v for 1-2 minutes instead of 6v.
Can this damage the tube?
Thanks

 

[k brown]

If the filament didn't burn out, it won't impact the function of the tube, but it will have shortened it's life.

 

[pucho812]

Yeah assuming the filament didn’t completely fail you have just taken hours off the tube life.

 

[Tubetec]

Heater volts are specified +/- a % in tube service docs ,factory heater burn in might already encompass an over voltage by a considerable margin ,over a short period of time ,

If on test (presumably with the tube mic circuit you envisage) the tube performs satisfactorily ,treat it as good .

 

[elskardio]

The tube still works in the microphone (m49 style) but I have a feeling there’s less bass frequencies than before the incident… I have an other 6s6b on the bench. I will swap them to double check
Thanks