Poll: How about a WD DIY kit Vacuum Tube tester

[Sid and Coke]

Nothing special and aimed specifically at the types of valves that are used on the current range of WD amplifiers.

When all said and done I'm sure that a commercial Vacuum Tube/Valve tester is just a box with a load of circuit boards and components installed, I bet there is nothing inside one that we don't already have installed in the valve amplifiers that some of us have already built.

A lot of the commercial designs probably have bespoke moving coil meters on them ( I'm thinking of the Good/Bad type here ) , but ultimately what are these meters showing ?
Is it anything that couldn't be reproduced using a stock OEM panel meter, or perhaps a row of Red, and Green LED's, or maybe a Numerical LED panel display.

I'm sure amny of us have bought a job lot of 'sold as seen with no guarantee' NOS valves of unknown quality , maybe with a nice simple metering device would enable the home enthusiast to sort the wheat from the chaff, or quickly test a suspect valve.

So Expert, just how difficult would it be to design and build a basic, functional and useful Valve tester ?

The reason that I'm asking is that commercial designs seem to be very expensive for what they are and what they do, pretty much the same reason that we design, buy and build DIY Hi-Fi amplifiers in the first place.

[david counter]

Hi S&C

have you seen this one

http://www.transcendentsound.com./tube_analyzer.htm,

[Sid and Coke]

Hi David, well yes i suppose there we go , that is probably something similar to what i was thinking of.

I should also add that I have never used a valve tester and don't actually know how one works.

If I'm being honest I was also thinking along the lines of something much cheaper than that too , perhaps even a 'dumb' testing rig that had 4mm sockets to plug an electrical multi meter, or megger that most of us own already to get the relevant readings.

[Shian7]

Damn fine idea!

[Richard]

Originally Posted by Sid and Coke

Hi David, well yes i suppose there we go , that is probably something similar to what i was thinking of.

I should also add that I have never used a valve tester and don't actually know how one works.

If I'm being honest I was also thinking along the lines of something much cheaper than that too , perhaps even a 'dumb' testing rig that had 4mm sockets to plug an electrical multi meter, or megger that most of us own already to get the relevant readings.

Unfortunately it's not so easy. To check a valve it first has to be heated. Then checked for insulation leaks. Then for conduction at different (high) voltages. The one linked to looks good and cheap for anyone who really wants to do this. I'd find out more about it but £300 for a new one looks pretty good these days as AVOs are £500-£1000 now for a good machine. Our own "home grown" one would be good!

[systemx]

I remember in the dim and distant past Mullard produced a tester that did notuse a meter. Instead a CRT display was used to indicate the readings. For each valve type there was a punched card that you inserted into a slot. when a small lever was pulled cown the card was locked in place and the connections were made. There used to be all sorts of flashers as interelectrode shorts cleared.
You could make a simple tester that treats the valve as a diode and measure the current passed compared to the reading of a new valve.

Terry

[Richard]

Ah, the "High Speed" Terry, I've seen them at jumbles with big boxes of data cards. There's a card for every valve in order to test it. I suppose we'd only need the audio numbers but the thing is useless without them.

The old hands said they were good/bad testers designed for the retailer to show customers and sell valves (pull the big handle and show them the display) as opposed to checking characteristics. I suppose good/bad though is all most folk would need to know.

Here some info,

http://www.thevalvepage.com/testeq/m...test/vtest.htm




Just noticed we were at that rally, lovely May day out, got some valves and a scope, sadly not at Drayton these days.

[systemx]

My God thats it, They were a bit more than just "good bad" testers and a go on this would sometimes get a reluctant valve to last perhaps a couple of months more (valves were always expensive). All this takes me back to when my father built our first television From a kit of parts. It had an ex RAF H2s radar tube about 4 inches across, everthing was green and white but I remember we all looked at it in wonder.