Probably the best explanation to date (Satirical) of how Tubes work. This is courtesy of www.unplggd.com. Had a nice laugh at this.
"We won't go into much detail as to how it works here- you can wiki it for more info. But briefly; a magical fairy flits about in the lightbulb-like structure using her little wand to make music louder. The manufacturer simply puts a little thimble of honey inside the tube to lure her in there in the first place. The fight against this heartless practice was one of the first crusades which brought PETA to the world stage, though, to be fair; fairies aren't animals."
Yeah Sure - And Conrad-Johnson amplifiers are made by Bill Conrad and Lew Johnson who are PhD Economists and once worked in Washington DC at the Federal Reserve. Oh. Hang on - They are!!!!!