So you are thinking of buying a valve (or tube) tester and perhaps wondering where to start.
The  type of tester you want to avoid are those that just check filament continuity – you can do that with a multi-meter. These are worthless.

Next up the food chain are the emission testers and most of these testers produce very credible results yet remain light and portable and very easy to use and read. Most of these testers will indicate internal shorts, gasiness and give you an indication of quality and by watching the tester you can get a feel for the life left in a valve.

If you are willing to spend more the best testers are mutual conductance testers but these are rarely truly portable and in the case of AVO machines definitely not portable and require some study of the manual before you can use them.

When buying a tester you must get the valve setting data with it or know where you can get the data from – you wouldn’t buy a computer without any software would you?  The question you need to ask  with valve data is if the copy you are supplied is up to date.  For instance B&K data tables have the date in code on the bottom left so 1273 would be telling you this was Dec 1973 issue of the data. Manufacturers issued 6 monthly or yearly updates and corrections in the 60’s and 70’s and if your booklet is dated 0665 you can be sure there are a lot of settings missing and some might be incorrect.

Most of the reasonably priced easy to use testers were made in the USA. The USA took the view that anyone should be able to plug a valve into a cheap tester and see easily if it was good or bad. The UK took the view that valve testing was something to be done in the laboratory by men in white coats and produced laboratory standard testers that will give you chapter and verse but you do need to concentrate when using them.  The USA ones are 110 to 120v testers. This is no problem as a step down transformer bridges the gap BUT there are some of these 115v testers than can suffer swamping of their small internal transformers when matched with some stepdown transformers that push out voltages in the 120+ range. These get real hot real quick.

If you see a tester for sale that has suffered by being stored in damp conditions and exhibiting a musty smell you are advised to steer clear as the dampness will have taken a toll of all the contacts and connections. If you see a tester with its mounting screws missing – steer clear as the previous owner didn’t even think it was worthwhile putting it back together after trying to fix the fault. If you see a tester with the plug missing – does this mean the previous owner thought the plug was the most valuable part of the tester or was it just so dangerous that he didn’t want anyone pluging it in. If you see a tester and cannot see the meter move this is a bad sign -  a dead or burnt out meter means the tester is probably worthless as your chances of finding a replacement are small.  A lot of testers are described as “untested but powers up” or “light comes on” but as many testers do not have a mains on lamp and the only light is the the shorts light and this should only light when a shorted valve is tested “light comes on “ when first plugged in can be a bad sign. As for “powers up” a valve tester does nothing until it is set up and a valve is fitted so all this is telling you is the fuse is good and it didnt burst into flames.  By and large testers are remarkable reliable and although most are 40 years old plus they are still in working order - wether they are accurate is another question of course.

You will see some testers that have a lot of sockets all the same size (say 15 off  B9A 10 off B7 and 8 octal etc)  and only two control knobs. Your first thought is that this type must test lots of valves as there are lots of sockets but this is incorrect as the range is limited and there is no flexibility. You will allways be better with a tester that has only say two or three sockets of each type but with 

a) three or four set up knobs and no levers or 

b)two (or more) knobs and a series of 10 (or more) switches or levers -

there is great flexibilty with either of these arrangements.

There are a lot of alternatives in the world of valve tester and it depends on your budget and what you want to do with a tester. I would suggest before you buy that “itchinaka Mk2” tester you talk to someone who has used a range of testers. You are welcome to use ebays ask me a question and tell me what you want from a tester and I will be more than happy to make some suggestions as to  what you might best be looking at -  for free!

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