3 interesting articles from AES, Journal of Elect Engineers, Eric Barbour

[300A]

Three articles, one from the Audio Engineering Society, one from Eric Barbour, and another from the Journal of Electrical Engineers:

http://www.spectrum.ieee.org/select/0898/tube.html

http://www.spectrum.ieee.org/select/0898/tubet1.html

http://www.dwfearn.com/tvst1.htm