Tube replacement

[bsco]

Received a Fender 65 Deluxe Reverb amp.....Customer supplied a complete set of tubes....he wanted the GT tubes replaced with JJ's......all of them.....so did that......set the bias at -37V as Fender specifies and plugged in one of my strats...Plays great but I noticed that there is a faint blue glow in the output tubes...when you play, the harder you hit the strings the more vivid the blue color is.....is this something to be concerned about or is this a normal by-product of the normal tube operation......just curious as I thought I had heard somewhere that this is nothing to be concerned about.......so I just wanted to check here with you guys..........(Just to be sure)
Cheers

[Enzo]

It is a matter of how hard the vacuum is within the tubes. SOme have harder vacuum than others. SO it is real common for tubes to have a small blue glow inside. A LOT of blue glow is something else. Tubes that do glow blue will naturally vary with the music.

[Leo_Gnardo]

It's "space charge." Most of the action takes place between the plates & grids & cathode, but sometimes you see lost electrons wizzing around in the space between plate & glass bulb, glowing brighter when current is near maximum.

Just tell 'em you're with the Lost Electricity Reclamation Agency and it's nothing to worry about.

[bsco]

It's "space charge." Most of the action takes place between the plates & grids & cathode, but sometimes you see lost electrons wizzing around in the space between plate & glass bulb, glowing brighter when current is near maximum.

Just tell 'em you're with the Lost Electricity Reclamation Agency and it's nothing to worry about.

hahahaaa.....I like that...well done...I will re-assemble it and give it a final test....Thank you very much Leo and Enzo for your input.....
Cheers