buying vacuum tubes and vintage electronic equipment on ebay can be a tricky thing . hopefully this may help you out . myself i have been working on vintage electronics off and on for over 25 years , even thou i still see things that still amaze me to this day. not only in repairing vintage equipment , but i also build tube type amps as a hobby mostly . when buying tubes check the feedback first !

does the person selling the tubes mostly deal in tubes and related items ? have the tubes been tested ? what are the test results ? dont be afraid to ask seller any questions about item tubes or vintage electronic equipment . most seller are more than happy to answer questions . most sellers offer these items `AS IS` , check feedback from sellers and or buyers who bought `AS IS` items and see what they have to say . `AS IS` is more or less a standard on ebay since the mfg warranty ran out many years ago or mfg is no longer in business also due to fragile nature of vintage electronic tubes and items .

when buying tubes it would be a good idea to buy a good tube tester . but then again a tube tester itself is a vintage piece of equipment . so i would get two or 3 of them and if 2 give the same or close to the same readings you know you got a good tester .  then you could resell the other testers and keep the one you like best.

tube testers come in all price ranges $10 to $1000 or more and some are harder to use than others . good tester should run about $100 . i would recommend a b&k 667 easy to use & solid state so no tubes inside to go bad . i myself have two testers the b&k 667 great for fairly accurate testing & a Hickok 533 much more techincal testing . both have +`s and -`s . b&k667 tests most tubes about 90%  ... except for old 4,5,6,7 pins tubes of the 20`s 30`s & 40`s . hickok 533 will test old 4,5,6 &7 pin tubes but won`t test `newer` large 9 & 12 pin tubes (compactrons) . so you can see that more than one tester maybe needed to test many different tubes. as for me i like both of these testers , but neither ones tests vintage european tubes like eb41,ech42,etc so you would need even another tester from europe. it all depends on what type of tube you want to test.

i mostly do this for fun now... because it is what i like to do .... the hunt for tubes & other items ... testing them &/or playing with them for a while and selling them as well . then i go out and do it all over again next weekend. some items i just like to collect ,other items i may buy just to scrap out for their parts needed for homebrew projects .. MY projects and for others out there that need vintage parts for their projects ... i even buy tubes here on ebay .. i like to compare others testers to mine to see how close the 2 are and i also buy tubes for some local customers/friends so if you see me bidding on tubes now you know why.

homebrewing  Guitar / Audio amps , Ham radio, RF amps and other stuff .