flashy blue light in power tubes

[gary sanders]

blue glow on the low notes.They are TAD 6L6GC.though you cant really hear anything wrong and all specs are good,what does this mean exactly?

i know some tubes have the glow but ive never seen any in an amp Ive ever owned do it this so intense to where you can actually see the tubes push pull process going back and forth.They were in a poorly biased bassman 165 and now I adjusted it to a true adjustable bias and they are set at 35-33 ma.when i first got the amp it was 29 and 12 with the original circuit.like someone found the "hum" pot and said hey what does this do?...

[tubeswell]

Blue is normal (and looks cooler in the dark )

[Gaz]

My understanding is that more blue around the glass means that the vacuum is a little soft. I don't really know exactly what that means though, considering it doesn't mean the vacuum's actually been lost. I've found it to be more common in well used tubes, however not exclusively. It does look awesome.

[Colossal]

I don't really know exactly what that means though, considering it doesn't mean the vacuum's actually been lost. I've found it to be more common in well used tubes, however not exclusively. It does look awesome.

Just means that, during manufacture, the atmosphere in the tube was not pulled down to a really hard vacuum, where the of quantity of gases remaining is the is truly very, very, very disperse. So when operating, the small amount of gases ionize and return to ground state, giving off lovely photons in the process. Like those cool plasma balls where you intentionally ionize cool gases like neon and argon.

[M Fowler]

Yeah what colossal said.

[gary sanders]

coolest amp light show I have ever seen.I'll make a video clip and post

[Colossal]

Yes it is. I put a pair of TAD 6L6 STRs in a local fellow's amp and they looked like they had a butane fire in them.

[jjman]

All the blue-glow tubes I've used would change intensity from playing. Even my SE amps during early clipping since they are also not biased in the middle of the swing potential. The glow gets fainter at that point, presumably from the voltage being lower from the (average) current being higher from the asymmetric clipping.

[TooL46_2]

This is a pretty nice effect -> http://www.youtube.com/watch?v=C3_-2fUm ... ure=relmfu

[Structo]

Whoa!

Those tubes really heat up when the bass kicks in.

http://historische-elektronik.piranho.d ... aerker.htm

Listen to this thing on the dummy load!

http://www.youtube.com/watch?v=QBAAF5UIzsA

[TooL46_2]

It is a MONSTER!

These tubes glow cause they are filled with Mercury vapor. It always makes me smile when I watch this video