Steve's Sounds - Steve Geiger's page, which includes excellent step-by-step photo galleries on construction of MAD and other kits.
Pacific TV (Victorial B. C.) - A supplier of new and used vacuum tubes at fair prices. Also check out some interesting ebay items for sale every week.
David Boardman (Quebec) - NOS and used tube sales. A large inventory at reasonable prices.
AudioCircle forum on Mapletree Audio Design products
Head-Fi Forum - Gathering place for headphone connoisseurs.
Head-wize - Another headphone forum.
Tube CAD Journal - Really thorough information on all tube design topics.
RadioMuseum.org
- Links and multi-language forum on antique radios