A real dumb Tube question

I'll give ya some glow...

Ed, are they the authors of "How to serve man"?

Slappy, this may seen like a put-on but it's not: I have heard, and seen, tweeters that glow. The Hill Plasmatronics speakers from the '70s used ionized Helium to produce sound. Sounded wonderful but required a big tank of Helium. Not many wives would put up with a big green tank. Back in the '50s there was the Dukane Ionovac tweeter, which ionized air rather than Helium. These also glowed but the electrodes wore down quickly in the presence of Oxygen. This is why Dr. Hill used Helium. Besides which, when one got tired of listening one could talk like Alvin The Chipmonk.

A tube is a light bulb with some extra wires in it. In most tubes the filiament glow can be seen. It glows red rather than white (like a light bulb) because it's purpose is to make heat, not light.

If there is a true vacuum in the tube it will not glow. If it does it means that a trace of air is leaking into the tube, and it is not going to last much longer.

I understand that some tubes have some gas (not air) in them by design. This gas may be excited by the electron flow, and glow.

Also, it's been mentioned that some glass has trace elements in it which glow when the tube is operating. This may be deliberate on the part of the tube manufacturer, because it looks sexy. I way about to say "it certainly doesn't affect the sound", but on this website...?

The only stupid question is the one you didn't ask!