Hello,
I recently purchased a quad of Sylvania 7591a tubes I put them in my amplifier
and fired it up....I noticed a blue haze inside the tubes,I never saw it with
my old tubes (also Sylvania 7591) is this common, or a sign of leaky or gassy
tubes?

Thanks for reading

On 06 Feb 2004 01:55:34 GMT, (Jeff S 386 Fla)
wrote:

Hello,
I recently purchased a quad of Sylvania 7591a tubes I put them in my amplifier
and fired it up....I noticed a blue haze inside the tubes,I never saw it with
my old tubes (also Sylvania 7591) is this common, or a sign of leaky or gassy
tubes?

Thanks for reading

May just be fluorescence, especially if around the envelope. Try
taking a picture of them with a digital camera - in the dark with no
lighting save the tubes. Depending on the camera you might get some
really nice effects.

Read the faq, see the pix:

http://members.aol.com/larrysb/blue_glow.html


In article ,
says...

Hello,
I recently purchased a quad of Sylvania 7591a tubes I put them in my
amplifier
and fired it up....I noticed a blue haze inside the tubes,I never saw it with
my old tubes (also Sylvania 7591) is this common, or a sign of leaky or gassy
tubes?

Thanks for reading

On Fri, 06 Feb 2004 01:55:34 +0000, Jeff S 386 Fla wrote:

Hello,
I recently purchased a quad of Sylvania 7591a tubes I put them in my
amplifier and fired it up....I noticed a blue haze inside the tubes,I
never saw it with my old tubes (also Sylvania 7591) is this common, or a
sign of leaky or gassy tubes?

Thanks for reading

Later Sylvania & Philips ECG tubes used bulbs that had a lot
of residual phosphorus in the glass , which glows blue when
stray electrons hit it. Some Russian tubes display a lot of
blue glow for the same reason. So do some GE tubes, because
in later years, they were buying bulbs from Sylvania....


--
Ned Carlson Triode Electronics Chicago,IL USA
www.triodeelectronics.com

thanks to everyone who informed me about the blue glow

you guys make the RAT what it is