DIY valve tester - Is it worth it?

[Crystaleyes]

A bit of a random question, but I was just wondering about the feasibilty/reality of buiding a valve tester?

This is something I have never looked into, but seems like here would be a good place to ask.

Anyone here ever done (or tried to do) this?

[eccerr0r]

Re: DIY valve tester - Is it worth it?

for specific tubes, it's been done; for general tubes... that has always been a problem. All those pinout charts are there for a reason, including those ancient kiosks that have a hundred sockets because of the pinout problem...
BTW that's just if you just want emission only; versus if characterization tracing/gm/... is also needed, that's even harder to make a general solution.

[Crystaleyes]

Re: DIY valve tester - Is it worth it?

So far, I've never 'worked' with any valve system, other than swapping the valves on our guitar amps, back in the day... However, I do keep coming across them on sale for pennies in the local street markets and it would be good to have a simple way to verify whether they are good or not, without having to splash out on a Hickok or similar.

Might be a good little earner, as some valves are not cheap.

[stj]

Re: DIY valve tester - Is it worth it?

you can get schematics of old testers,
as for the 100 sockets/pinouts issue, you could use a load of relays and a microcontroller to configure the pinouts

[eccerr0r]

Re: DIY valve tester - Is it worth it?

Effectively you'd need a n^2 switch tree where n is the max number of pins plus top caps...

I suspect if you want to make a tester solely for 6BQ5, 12AX7, and 6146B's it'd make things a lot easier.

BTW I have a portable tube tester but it's short/open/emission-only and only has the common 1930's+ tubes I think. Uses multiposition switches to deal with the n^2 relay bank mess and very manual... Good enough for go/no go, but can't match tubes.

[eccerr0r]

Re: DIY valve tester - Is it worth it?

So which tubes are people still interested in?

TBH I don't think I'm really interested in any tubes though the 6146's are still kind of interesting (as a ham). Which incidentally my tube tester cannot test... Alas I don't have any of these, just the cheap old 12AX7's, 12BA6's, 12BE6's, 50C5's, 35W4's, 12AT6's, ...

[Crystaleyes]

Re: DIY valve tester - Is it worth it?

Thanks for all the input, it was just an idea... I still think that if I come across another box of dirt cheap valves then I'll pick them up, if only just to offer them to a wider public.

I often see valves such the 12AX7's and the like for a Euro (or less) which will just get binned if no-one buys them.

[eccerr0r]

Re: DIY valve tester - Is it worth it?

As with any goods, tubes are expensive only if demand exceeds supply ...
probably zillions of 12AX7's out there but thought there was still a demand for them as they make good preamps that give people the "tube sound" (what?) experience.

Alas I'm all solid state for audio, don't give a crap about "tube sound". But 6146's are blown quite frequently trying to make another contact...

(the 12BA6's, 12BE6's, 50C5's, 35W4's, 12AT6's are all used for AA5 radios and since there were a zillion of these around, there are zillions of these tubes around, and thus likewise worthless. And who uses AA5 radios anymore, even if it's for AM...)

[stj]

Re: DIY valve tester - Is it worth it?

there are huge stocks of valves in eastern europe, but postage would be a bitch.
and huge piles of boxed spares dumped in abandoned soviet bases too - seen video of it.
they prefered valves over transistors because they are less effected by emp etc.