This page keeps some good vendor's information.

Online Store - Part Express

Online Store - Antique Electronics

Online Store - Digkey (Toroid Transformer, other electronics)

Online Store - Marchang Electronics Inc.

Online Tube Store - TubeDepot

Online Tube Store - http://www.boiaudioworks.com/

Online Tube Store - http://store.triodestore.com/6bel71elsv.html

Online Tube Store - http://thetubestore.com/

Online Tube Store - http://www.fourwater.com/audio/audio_au26.htm

Online Tube Store - http://tubes2u.com/7au7-11ms8.htm

Reference

http://greygum.net/sbench/sbench101/ - my favor, learn so much from Steve's article

http://thejaffes.org/rory/mintube.php http://amps.zugster.net/projects/subminiature

http://jjs.at/electronic/class_a_subminiature.html - with switch power supply

http://www.whiplashaudio.com/mini-millet-diy-tube-amplifier.html

http://diyaudioprojects.com/Tubes/6T9-Tube-Amp-Kit/

http://greygum.net/sbench/sbench101/

Tool

Tube Database

Schematic Drawing Tool

ZVEX - Tiny Gituar Amp

How to test output transformer