Tube Question about blue Glow

[bobb6k34]

i have 6l6's and the tubes glow blue. i read that thats fine but then other places say its not, it only happens when the amp is on and im playing it and goes away when i flick into standby.

[mr. ricacu]

Isnt that air inside the tube?

Correct me if im wrong

[bobb6k34]

yer i read somewhere that it's gassy tubes... im not shore what that means to be honest

[overdriver]

The answer ya seek is here in the resource section www.kcanostubes.com

[overdriver]

^ if you don't want to take the time to read all about , it is fine nothing to worry about.

[LoKi]

It's fine. Tubes are only bad when they're blown, or starting to sound bad. Even when they are sounding bad, they are still functionally ok, it's just a matter of preference for tone. You can tell if their dying by tapping on each one with a pen lightly while the amp is on. If you can hear the tapping really loudly through your speakers, they're on their way out.

Standby is just the plate warmers on, so not a lot of voltage is going through the tubes, that's why it only happens while you're playing.

[b-squared]

Very Pretty...great avatar pic there.

BB

[bobb6k34]

thanks guys , just wonted to ensure there fine. there new with the amp

Originally Posted by b-squared

Very Pretty...great avatar pic there.

BB

its my desktop Pic atm... might turn it into a sig or somthing when i get the time :P

[overdriver]

Originally Posted by mr. ricacu

Isnt that air inside the tube?

Correct me if im wrong

air in a vacuum !?

[Blues Power]

a lil blue is normal. but imo that looks a little excessive. being that all 4 are even tells me it most likely not a big prob but id still have them benched tested and get the biasing looked at.

my tech explained it to me once but i forget. i think is has to do wth the sealing process in the mfg plant

[ES350]

That looks allright to me...my quartets of Philips 7581A's glow the nicest shade of blue/violet. Nothing wrong with them or the amp...

[lineboss58]

Originally Posted by overdriver

air in a vacuum !?

Air in a vacuum? Oh yes indeed, it is not possible to remove all atmospheric gasses from a tube. The best tube factorys had the best pumping techniques to evacuate as much gas as possible, the heater filament is coated with a "getter". The first time the heater is turned on it vapourises the getter which nutralizes any contaminants left in the tube, this is the silver residue you see coated on the inside glass of the tube. Hope this helps.

[overdriver]

Originally Posted by lineboss58

Air in a vacuum? Oh yes indeed, it is not possible to remove all atmospheric gasses from a tube. The best tube factorys had the best pumping techniques to evacuate as much gas as possible, the heater filament is coated with a "getter". The first time the heater is turned on it vapourises the getter which nutralizes any contaminants left in the tube, this is the silver residue you see coated on the inside glass of the tube. Hope this helps.

Thanks for that!