Blue Glow on 1 tube

[TheRazMeister]

hey guys, I mistakenly posted a "popping noise" post on the Vintage section. Basically my ROV combo plays fine for 20 seconds, pops/crackles, loses volume, then has a slight hum. From that point on the standby switch will pop when switching it to standby.
I noticed a blue glow on 1 of my 2 E-34L's (JJ's) that would flash when I set it to standby. I called Eurotubes and spoke to Jay who said to clean out the contacts (not sure why that would be since they worked fine for 2 months). he wouldn't answer my question on why only 1 tube did this. Anyone have ideas?

 

[Platypus]

Prob a bad tube.. is it a normal orange glow then a blue flash?

All my JJ EL34L's glow normal, when my JJ rectifier was going bad, it would flash blue.

 

[TheRazMeister]

The blue stays constant until I flip the stanby switch....I guess I've never really looked at my tubes and for all I know, the blue one is good and the other is bad :?

Prob a bad tube.. is it a normal orange glow then a blue flash?

All my JJ EL34L's glow normal, when my JJ rectifier was going bad, it would flash blue.

 

[ylo]

A little blue glow is entirely normal and does not indicate a bad tube.

 

[Guitarzan]

Glass tubes have visible glow inside them. Most audio types use oxide-coated cathodes, which glow a cheery warm orange color. Some newcomers to the tube-audio world have also noticed that some of their tubes emit a bluish-colored glow. There are TWO causes for this glow in audio power tubes; one of them is normal and harmless, the other occurs only in a bad audio tube.

1) Most glass power tubes show FLUORESCENCE GLOW. This is a very deep blue color. It can appear wherever the electrons from the cathode can strike a solid object. It is caused by minor impurities, such as cobalt, in the object. The fast-moving electrons strike the impurity molecules, excite them, and produce photons of light of a characteristic color. This is usually observed on the interior of the plate, on the surface of the mica spacers, or on the inside of the glass envelope. THIS GLOW IS HARMLESS. It is normal and does not indicate a tube failure. Enjoy it. Many people feel it improves the appearance of the tube while in operation.
2) Occasionally a tube will develop a small leak. When air gets into the tube, AND when the high plate voltage is applied, the air molecules can ionize. The glow of ionized air is quite different from the fluorescence glow above--ionized air is a strong purple color, almost pink. This color usually appears INSIDE the plate of the tube (though not always). It does not cling to surfaces, like fluorescence, but appears in the spaces BETWEEN elements. A tube showing this glow should be replaced right away, since the gas can cause the plate current to run away and (possibly) damage the amplifier.
PLEASE NOTE: some older hi-fi and guitar amplifiers, and a very few modern amplifiers, use special tubes that DEPEND on ionized gas for their normal operation.

-Some amps use mercury vapor rectifiers, such as types 83, 816, 866 or 872. These tubes glow a strong blue-purple color in normal use. They turn AC power into DC to run the other tubes.
-And occasionally, vintage and modern amplifiers use gas-discharge regulator tubes, such as types 0A2, 0B2, 0C2, 0A3, 0B3, 0C3 or 0D3.
These tubes rely on ionized gas to control a voltage tightly, and normally glow either blue-purple or pink when in normal operation. If you are unsure if these special tubes are used in your amplifier, consult with an experienced technican before replacing them.

 

[TheRazMeister]

Thanks Guitarzan....awesom response...now what the popping noise 20 seconds after I turn on the amp
BTW - it does it EVERY TIME!

Glass tubes have visible glow inside them. Most audio types use oxide-coated cathodes, which glow a cheery warm orange color. Some newcomers to the tube-audio world have also noticed that some of their tubes emit a bluish-colored glow. There are TWO causes for this glow in audio power tubes; one of them is normal and harmless, the other occurs only in a bad audio tube.

1) Most glass power tubes show FLUORESCENCE GLOW. This is a very deep blue color. It can appear wherever the electrons from the cathode can strike a solid object. It is caused by minor impurities, such as cobalt, in the object. The fast-moving electrons strike the impurity molecules, excite them, and produce photons of light of a characteristic color. This is usually observed on the interior of the plate, on the surface of the mica spacers, or on the inside of the glass envelope. THIS GLOW IS HARMLESS. It is normal and does not indicate a tube failure. Enjoy it. Many people feel it improves the appearance of the tube while in operation.
2) Occasionally a tube will develop a small leak. When air gets into the tube, AND when the high plate voltage is applied, the air molecules can ionize. The glow of ionized air is quite different from the fluorescence glow above--ionized air is a strong purple color, almost pink. This color usually appears INSIDE the plate of the tube (though not always). It does not cling to surfaces, like fluorescence, but appears in the spaces BETWEEN elements. A tube showing this glow should be replaced right away, since the gas can cause the plate current to run away and (possibly) damage the amplifier.
PLEASE NOTE: some older hi-fi and guitar amplifiers, and a very few modern amplifiers, use special tubes that DEPEND on ionized gas for their normal operation.

-Some amps use mercury vapor rectifiers, such as types 83, 816, 866 or 872. These tubes glow a strong blue-purple color in normal use. They turn AC power into DC to run the other tubes.
-And occasionally, vintage and modern amplifiers use gas-discharge regulator tubes, such as types 0A2, 0B2, 0C2, 0A3, 0B3, 0C3 or 0D3.
These tubes rely on ionized gas to control a voltage tightly, and normally glow either blue-purple or pink when in normal operation. If you are unsure if these special tubes are used in your amplifier, consult with an experienced technican before replacing them.

 

[Guitarzan]

The popping noise usually is accompained by a crackling noise. This is just the tubes warming up. Typically the popping/crackling goes away after the tubes get toasty. Is this what your hearing? I had a GT 12AX7M that was just horrible for the first 5 mins or so then it would just go away...

 

[TheRazMeister]

The issue isn't so much the popping noise, it's that immediately after that I get a slight hum in what used to be a dead quiet amp. I also feel like there is a slight tonal change so my guess is that it's not a normal event.

The popping noise usually is accompained by a crackling noise. This is just the tubes warming up. Typically the popping/crackling goes away after the tubes get toasty. Is this what your hearing? I had a GT 12AX7M that was just horrible for the first 5 mins or so then it would just go away...

 

[TheRazMeister]

Update, put in STR-454 Mesa branded Svetlana 6L6's.....noise is gone and standby switch popping noise eliminated. Called Bob at Eurotubes and he asked that I try a few things, mainly to eliminate any issues with contacts.

BTW - I LOVE THESE SVETLANA'S The cleans are absolutely wonderful...at least compared to the E34L's...and mind you, I'm a high gain player. 8)

 

[hectitor]

I have a Triple Rectifier and the 2 power tubes of extrme are glowing ligth blue, when I play, the left one glows more, like a blue line flash which touches glass, , and most incandecente, and smells like ozone, I changed te external tubes with centrail pair, because I tougth it was a tube issue, but it has the same "problem" The amp is almost new!!!

This is ok or not?
HEEELP ME PLEASEEEEEEE

 

[94Tremoverb]

Definitely a fault if you're seeing arcing in the tube.

Do you mean that the same tubes still flash, or the same sockets? If the fault moved with the tubes, the tubes are responsible. If it staying in the same sockets with different tubes, it's some other problem.

Just to be clear, you didn't mix up rectifier tubes with power tubes? (!)