Power tube glowing blue?

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SwampDonkey

SwampDonkey

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I have heard from some that this is a non issue, but I am not sure I agree. I have one power tube that has just started glowing blue. Many of you here know your amps very well, so I am asking you fine people if this is an indication that the tube is about to fail, or is it normal?

There is no 'lightning', just a blue glow at the very top of the KT88. No sound issues, no popping or any other anomalies. No volume drop.

Help! :confused:
 
That's totally fine.

I can't remember the scientific details about why it happens but, yeah, don't worry about it.
 
Thanks Lester! I was curious what was actually going on.
 
SwampDonkey":dn52w0ex said:
I have heard from some that this is a non issue, but I am not sure I agree. I have one power tube that has just started glowing blue. Many of you here know your amps very well, so I am asking you fine people if this is an indication that the tube is about to fail, or is it normal?

There is no 'lightning', just a blue glow at the very top of the KT88. No sound issues, no popping or any other anomalies. No volume drop.

Help! :confused:
Click to expand...

Fitzgig tempts me in from remission.

It's kind of interesting actually. They use tungston-based filiments in light bulbs and in vacuum tubes and in heating elements, but for completely different properties. Heat is a side effect in two cases. Light is a side effect in two cases. Free electrons is a side effect in two cases.

Basically saying, the exact choice of filiment material in a vacuum tube has to do with how it excites electrons to be used in a current source. The light changes depending upon how the filiment is engineered, but it is entirely inconsequential. I see a lot of blue and red. But it doesn't matter.

I think vacuum tubes burn out like light bulbs. The whole filiment just pops and comes apart. There would not be a discernable change in color as it dies. Be cool if it did though. Make it easier to know when to buy new tubes.
 
srinivassa":1tk80pzk said:
Fitzgig tempts me in from remission.

It's kind of interesting actually. They use tungston-based filiments in light bulbs and in vacuum tubes and in heating elements, but for completely different properties. Heat is a side effect in two cases. Light is a side effect in two cases. Free electrons is a side effect in two cases.

Basically saying, the exact choice of filiment material in a vacuum tube has to do with how it excites electrons to be used in a current source. The light changes depending upon how the filiment is engineered, but it is entirely inconsequential. I see a lot of blue and red. But it doesn't matter.

I think vacuum tubes burn out like light bulbs. The whole filiment just pops and comes apart. There would not be a discernable change in color as it dies. Be cool if it did though. Make it easier to know when to buy new tubes.
Click to expand...

Not many people know what that is in my avatar! :lol: :LOL:

Ok, so then why would 1 out of 4 matched tubes suddenly start glowing blue after hours of play? I understand it's not going to be a problem, but now you guys have me interested in the science of it.
 
Blue Means There are impuritys or gas inside the tube... That is emitted from the metal plates glowing.

The "Getter" (The Chrome Stuff on top of the Glass), Absorbs the Gas... When the Getter can no longer absorb anymore, the Glass built up in the tube glows Blue...

It's a sign that the tube is at the end of it's life... That Gas can Arc so it's replacement time, or if the tube is new it means that the parts were not baked enough to get the impuritys out before building the tube.

Roid RAGE
 
SwampDonkey":2jhcw7d9 said:
I have heard from some that this is a non issue, but I am not sure I agree. I have one power tube that has just started glowing blue. Many of you here know your amps very well, so I am asking you fine people if this is an indication that the tube is about to fail, or is it normal?

There is no 'lightning', just a blue glow at the very top of the KT88. No sound issues, no popping or any other anomalies. No volume drop.

Help! :confused:
Click to expand...
Take a look at this http://thetubestore.com/blueglow.html
 
As far as I know, what everyone has said so far is right on. A little blue glow means some gas is in the tube (not a big deal). As long as the tubes are still lit I would not worry. As long as the tube does'nt turn as bright and blue as the LED on the MXR carbon Copy, I wouldnt worry.
 
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