I'll edit and update this entry as I go rather than continually add new posts
Information Resources:
the place I always start when I need info on valves is;
http://tdsl.duncanamps.com/ click on the software tab and you can download a personal copy of the search database to hold on your PC. Or use the online search, this (and the PC version)has links to data sheets.
http://hktubeaudio.homestead.com/ the Hong Kong Tube Audio Club - go to the main menu option & tube info for their tube shoot-outs.
http://www.jj-electronic.sk/ JJ valves home site
*A book worth reading "A Taste of Tubes"* Download or view from the link below
http://www.anthemav.com/OldSitev1/pdf/taste.pdf
Western Electric links - this link takes you into their archived tube spec sheets, but there are other interesting sections to go to as well
FAQ section from Vacuum Tube Valley
http://www.vacuumtube.com/FAQ1.htm
The Vacuum Tube Inc. "Hall of Shame" an article about some of the more common fakes and poor re-brands, some even perpetrated by the manufacturers themselves.
http://www.vacuumtubesinc.com/VacuumTubesHallofShame.aspx
Weber Valve Bias Calculator
http://www.webervst.com/tubes/calcbias.htm
The BoatAnchorManual Archive
http://bama.sbc.edu/
It's big, it's American,it's flaky, it's got a strange name, but if you're looking for a manual on vintage Americana stuff, it the place to start, more odd manuals than you can shake a stick at! Patience and the refresh key are all you need (unless the file is in DjVu format, then you'll have to download the viewer - but its free). They also have a mirror site with all the same stuff again at;
http://bama.edebris.com/manuals/
Sellers WEB based:
http://www.tubetown.de good prices for new tubes (cheaper in many cases than the UK)reasonable postage, mainly a muso' site but still OK for audio stuff.
http://www.chelmervalve.co.uk/index.htm probably the biggest stock of NOS valves in the UK (least thats what they say)
http://www.tube-shop.com/uk/home.asp Every one's favourite?
Well certainly not mine - totally useless, inefficient bunch who I've never managed to have one successful trouble free purchase from.
https://www.watfordvalves.com/order_frameset.htm Another of the usual suspects – watch out for that postal charge if you only want a single valve
Sellers eBay (that have provided good service):
big.daddy! (shop is
10x10 Electronics )
vintagelectron (US based, but I've had batches of tubes shipped over that have been cheaper than in the UK, even when you add in delivery and tax!)
tubeprofi (shop is
TubeProfi Shopbased in Austria) usually good prices for new JJ's
Testers General Reading:
Good reading for testers in general, but especially for US ones
http://tone-lizard.com/tube-testers/
Testers, New Production:
http://www.amplitrex.com/the best looking high tech' one I've seen so far - no USB Connection though
http://www.hagtech.com/vacutrace.html
http://www.vacuumtube.com/toppage31.htm
http://www.transcendentsound.com/tube_analyzer.htm
http://www.britishaudio.co.uk/tubeimp.html
http://www.maximatcher.com/
Testers Old:
http://www.crowthornetubes.com/valvetest.htmusually has somethingof interest, but be careful and research before you buy.
Tutorial resources:
Download
the Audio Classroom Series from AudioXpress
These
Selected sections are very useful.
Edit to update old closed link + Add a new link