The electron vacuum tube is a marvelous device. It makes possible the performing of operations with precision and amazing in conception, like in the vacuum tube audio amplifiers.
I believe that this web site is the most practical way to introduce a number of tube amps DIY audio applications for those who not only like to construct but listen to music as well.

Knock, knock, knockin' on heaven's door..
Knock, knock, knockin' on heaven's door..

Lyrics by Bob Dylan