AIKEN AMPLIFIERS
Good articles and technical info

AMPAGE
One of the best forums for amps and effects

AMPLIFIER CHASSIS PICS
Take a peek at the guts of your favorite amp

THE AX84 COOPERATIVE TUBE AMP PROJECT
Great projects and information, plus a very friendly and helpful forum. This is THE BEST place to begin if you’re new to DIY

THE BLUE GUITAR
A ton of amp schematics and modification information

DUNCAN’S AMP PAGES
This site features a tube data search engine and best of all, a Tone Stack Calculator.

THE 18 WATT COMMUNITY CENTER
Thriving online DIY community devoted to the Marshall 18-watt amplifier

LONDON POWER
Kevin O’Connor builds a full line of innovative amplifiers; he also writes the most authoritative books on the subject. The Ultimate Tone, Vol. I is by far the best and most comprehensive book on guitar amp design ever written

GUITARGEARY

GuitarGeary.com is one of the best blogs for guitar equipment reviews and HQ advice from pros.

SCHEMATIC HEAVEN
Looking for tube amp schematics? Look no further – schematicheaven.net

SLOCLONE FORUMS
Discussion forum devoted to high-gain DIY

WEBER DISCUSSION FORUMS
Discussion forums for speakers, tubes, amps, and guitars. Also has links to many other popular forums