BLue hue

Brap · 17th March 2004, 07:57 PM

Probably nothing to worry about, but after about an hour or so, I 'm getting a slight blue hue from my 2A3 tubes on one channel alone of a 2 channel amp. I thinking it's slight manufacturing debris in the tubes?

thanks

Colt45 · 17th March 2004, 08:06 PM

On the glass, or in the elements?

Brap · 17th March 2004, 08:09 PM

It's on the glass portion, near the "shoulder" if that 's the correct terminology

Sch3mat1c · 17th March 2004, 09:48 PM

Perfectly fine. I even have a 6SN7 that does it.

Tim

PeteM · 18th March 2004, 12:09 AM

Sounds perfectly normal Enjoy

fdegrove · 18th March 2004, 12:38 AM

Hi,

Maybe someone should explain, once again, where the blue hue comes from and how it will affect the useful life of a tube?

Don't ask, it won't be me doing the 'splaining again.

Cheers,

Sch3mat1c · 18th March 2004, 02:28 AM

Quote:

Originally posted by Brap
It's on the glass portion, near the "shoulder" if that 's the correct terminology

Quote:

Originally posted by fdegrove
Maybe someone should explain, once again, where the blue hue comes from and how it will affect the useful life of a tube?

Yeah yeah, blue glow on glass is perfectly fine, blue/purple/white glow from inside the structure might not be. I have some Russian 6L6s (erm.. 6pi3C-E or whatever) where the plate coating fluoresces light blue where the electron beam strikes it. I can barely see (due to visual obstructions and low current) the same in Hept'AU7's 12AU7s too. The real thing that you should worry about is a discharge between the cathode and plate, not a generic glow from inside.

Tim

Duo · 18th March 2004, 02:41 AM

Yeah, this is pretty simple. There are often just impurities in the glass or elsewhere in the tube that are easy to ionize and also emit light when this occurs. If the color shows right on the glass and not just floating inside the tube, then I see no problem.

I, like others here, have had tubes with a light glow on the glass or plates. They usually give me plenty of fine operation just like a tube that doesn't glow unusually.

Majestic · 20th March 2004, 05:25 AM

I've got one set of Philips/Siemens EL34's that do this.

I've never observed any sonic difference or penalty from having a blow glow from a set of tubes, but I've got to say thay look damn fine when listening to music in a darkened room!

17th March 2004, 07:57 PM	#1
Brap diyAudio Member Join Date: Jan 2004 Location: Chicago, Ill	BLue hue Probably nothing to worry about, but after about an hour or so, I 'm getting a slight blue hue from my 2A3 tubes on one channel alone of a 2 channel amp. I thinking it's slight manufacturing debris in the tubes? thanks

17th March 2004, 09:48 PM	#4
Sch3mat1c diyAudio Member Join Date: Jan 2003 Location: Milwaukee, WI	Perfectly fine. I even have a 6SN7 that does it. Tim __________________ See my Electronics webpage -- the home of Vacuum Tube Drag Racing. The key to being a successful Audiophile: "I reject your reality and substitute my own!"

18th March 2004, 12:38 AM	#6
fdegrove diyAudio Senior Member Join Date: Aug 2002 Location: Belgium	Hi, Maybe someone should explain, once again, where the blue hue comes from and how it will affect the useful life of a tube? Don't ask, it won't be me doing the 'splaining again. Cheers, __________________ Frank

18th March 2004, 02:41 AM	#8
Duo diyAudio Member Join Date: Jun 2002 Location: Victoria, BC, Canada	Yeah, this is pretty simple. There are often just impurities in the glass or elsewhere in the tube that are easy to ionize and also emit light when this occurs. If the color shows right on the glass and not just floating inside the tube, then I see no problem. I, like others here, have had tubes with a light glow on the glass or plates. They usually give me plenty of fine operation just like a tube that doesn't glow unusually. __________________ -- Duo, W1ngs, VA7MON, and lesser known handles. -- -- http://www.w1ngselectronics.com -- My Work and Projects --

20th March 2004, 05:25 AM	#9
Majestic diyAudio Member Join Date: Mar 2004 Location: Melbourne	I've got one set of Philips/Siemens EL34's that do this. I've never observed any sonic difference or penalty from having a blow glow from a set of tubes, but I've got to say thay look damn fine when listening to music in a darkened room! __________________ check out my avitar and go easy on me ok? :-)

17th March 2004, 08:06 PM	#2
Colt45 diyAudio Member Join Date: Feb 2002 Location: Canada	On the glass, or in the elements?

17th March 2004, 08:09 PM	#3
Brap diyAudio Member Join Date: Jan 2004 Location: Chicago, Ill	It's on the glass portion, near the "shoulder" if that 's the correct terminology

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