For Tube Enthusiasts - a Gratuitous Link to Russian Tubes (Specs

[SVL]

and US analogs):

General List (more links from there) (http://www.next-power.net/next-tube/datasheets.php3)

American Tubes and Their Soviet Analogs (Adobe PDF) (http://www.next-power.net/next-tube/Data/USA-RUS.pdf)