tubebooks.org – Vintage info from the days of vacuum tubes: a collection of vintage engineering texts, vacuum tube datasheets, and other obsolete information, presented free of charge and without annoying advertisements.
WorldRadioHistory.com – A vast online repository containing digitised copies of vintage wireless, broadcasting and electronics magazines and technical books.
AudioTubes.com (Brent Jesse Recording and Supply Inc.) – New old stock tubes, valves, tube testers and other geek stuff and very knowledgeable on tubes.
Patuxent Communications – Receiving, Transmitting and Special Purpose Tubes & Other Classic Electronic Parts.
The Tube Center – Buy, sell and swap vacuum tubes.
Old Guy Radiola – Sells tubes on Ebay. Very good prices and they are prepared to haggle and barter.
Tube Museum New York – Tested and graded tubes.
Angela Instruments – NOS Tubes and other guitar and vintage amp parts.
TheTubeStore.com – Audio tubes for any amplifier from high-end home audio to classic guitar amps. Also a good resource for information on tubes.
TubeDepot.com – NOS and new manufacture tubes. They also stock electronic parts, books and amplifier kits. I built one of their Fender ‘Tweed’ amp kits.
Langrex – Electronic valves and components. Specialising in original British, German and American tubes. Langrex carry large stocks of NOS tubes and we’ve found their tubes to be the cleanest, quietest and most authentic (original silkscreen print, no attempts to clean corroded tube pins, no grading to weed out any defective tubes in a bad batch and no cryogenic treatment to try and improve tube performance characteristics) on the market.
KarlTone – Valves, Speakers, Guitar and Pro Audio Accessories. Helpful and friendly service and some of the best prices for JJ tubes on the market. They also test and match their JJ tubes.
Watford Valves – Watford Valves is a U.K company that was established in the early 1990s’ and has become one of Europe’s leading suppliers of tested, graded and guaranteed valves and components to the professional music and audio industry.
Billinghurst Export Limited – UK supplier of electronic tubes and valves. Their NOS tubes are some of the lowest priced on the market, but their quality is somewhat hit and miss (excessively microphonic and noisy). They do, however accept any returns on a no quibble basis.