Tube flash question

I have recently acquired a pair of Mullard Ecc83 (12AX7) valves.
The issue I have is when I turn my amp on, one tube emits a bright flash and the other does not.

Is this normal? Does it mean that the tube that didn't flash might not be a genuine Mullard?

Amp sounds great so not really an issue but just wanted to check as they weren't cheap.

 

The flash on start-up is fairly normal with Mullard NOS valves. Nothing to worry about. I have one ECC83 that flashes on start-up and five that don't.

 

yup, normal with the smaller signal valves... my Mullard 12at7`s do it, so do my new EI`s

 

So do Mullard GZ32 rectifier tubes

 

what do rectifier tubes rectify?

 

A rectifier is an electrical device, which converts alternating current to direct current, a process known as rectification.

Rectifiers are used as components of power supplies and as detectors of radio signals. Rectifiers may be made of solid state diodes, vacuum tube diodes, mercury arc valves, and other technologies.

Hope that explains it Kmac

 

it does thanks - I also since looked it up online.