VALVULAS

http://www.banzaieffects.com/home.php
http://www.hotroxuk.com/matched-valves-links-page-909-0.html
http://www.analogmetric.com/forum/index.php
http://diyaudioprojects.com/Schematics/7025-12AX7A-Tube-Phono-Preamplifier-Schematic.htm
http://diyaudioprojects.com/Tubes/tubes.htm
http://www.pmillett.com/index.html
http://www.next-tube.com/programs.php
http://store.tubedepot.com/

Bela colecção

Outro.
http://www.techtubevalves.com/