Comment

Comment by Steph S. on May 21, 2012 at 11:40am

looks like

Comment by James Yount on April 12, 2012 at 4:51am

Looks cool! Is that electrons jumping from one orbital shell to the other like in neon lighting? And what were the bottles used for?

Comment by Richard ∑wald on April 12, 2012 at 4:15am

"I haven't been an EE major long enough"

Old school, unless you find an old geezer… you'll probably never learn about bottles. They stopped including them in courses …probably about 35 years ago.

Looks like this when grid bias is correct:

When the bias is either way to hot or in "runaway", they glow deep red and eventually melt a hole through the glass.

That nice blue glow is the electrons interacting with stray particles in the bottle, plasma. Even when running at spec, elements of the tube are hotter than the surface of the sun.

Comment by James Yount on April 12, 2012 at 3:31am

I haven't been an EE major long enough to know what a 6L6-GT is, but I can imagine current overload that you're talking about.  The most dangerous electrical accident I ever witnessed was a backhoe hitting a primary service lateral. The resulting explosion turned the sand to glass.

Comment by Richard ∑wald on April 12, 2012 at 3:23am

Watching a 6L6-GT with ruaway bias and 750v 5a going through it is almost hypnotic, until you realize what it can take with it and kill power. It really sucks when it happens at a gig.

It's amazing to watch a beam of electrons from, basically just a modded light bulb; melt through metal and glass though.

Comment by James Yount on April 12, 2012 at 2:52am

I've been an electrician for 8 years, so working with 5 volts is certainly a pleasant change.

Comment by Richard ∑wald on April 12, 2012 at 2:45am

Just be happy that your voltages are low enough that the "lead dress" can't induce a melt-down, ha ha...

~ Richard (high-voltage thermionic vacuum tube experimenter, who has seen melt-downs)