Blue glow in power tubes (A15Mk2)

Hi,

I finished my amp yesterday, so I put the tubes and turned on the amp.
When I turned on the main switch, only the heater was glowing in all the tubes, but a minute later, when I turned on the standby switch, appeared a blue glow in the power tubes, bigger at the V5, and the transformer's "hum" became a bit louder. I compared this morning the voltages with the schematic and they were OK. I don't know if it's normal or there's something wrong. ???

Best regards,

Juan.

Re: Blue glow in power tubes (A15Mk2)

I took some voltages of the power tubes, I attach an image with the voltages in "green".

Re: Blue glow in power tubes (A15Mk2)

Thanks Martin, I was almost sure when I interchanged the power tubes. The one that was in the V5 socket stills glowing more (now in the V6 socket) than the other tube, so I thought that this is a characteristic of the tube itself, and not a problem of the circuit.

Best regards,
Juan.