18 Watt.com
Board for aficionados of the Marshall 18 watt circuit. Lots of great info for builders of all levels.

Adam's Amps
Great blog on all things amp related!

The Airtight Garage
One of our first clients. Robert's amps are incredible.

AX84
Amazing ampbuilding site with lots of super helpful people that love to help each other build great amps!

DIY Tube Guitar Amp Page
Philip Ruetz' site is chock a block full of great info. Comprehensive list of amp builders.

Eric Nyberg's Amps
Eric's amps are nothing short of inspirational, and he's a very nice guy, to boot. Check out his articles on conjunctive filtering in a High Octane style amp.

Turretboards.com
Classic & Custom Turret boards.