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
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