Like many, I participate in various forums on the ‘Net, and I came across a plug for a fascinating article written in 1998 talking about devices that employ tubes – specifically amps and hi-end audio – and does a very good job of explaining why people gravitate towards tubed devices. Here’s the link to the article. It’s long, but worth it!
http://spectrum.ieee.org/consumer-electronics/audiovideo/the-cool-sound-of-tubes/0