DIY valve/tube tester

[JohnH]

While I was ordering some things I needed for my 18W build I decided I'd also grab some of the parts I need to try to build this Valveheaven DIY Tube Tester (https://valveheaven.com/2015/03/an-inexpensive-easy-to-build-diy-valvetube-tester/)

I think I have most of the capacitors etc, but need the transformer, enclosure, tube sockets and display units.

The one in the instructions uses two mini DMMs to take the readings, but I've seen some nice ones on the net where people used nice looking digital panel meters so I think I might do that instead - partly for aesthetics and ease of reading (I can read blue numbers on a screen much more easily) and partly to save some space in the enclosure.

One other option I thought about is to have banana plugs instead of any reading unit, so you connect two DMMs to the banana plugs to take the readings. I still think it's better to have everything contained in one unit, but it's an option to think about...

Suggestions/thoughts always welcome. I'll post some progress pics once I get everything together

[DrNomis_44]

Cool, I need to make one of these too.

[Simon Barden]

I'd look at the build picture of Johan's unit in that article. Those are the connector sockets you want. The basic banana plug ones in the bloggers build are potentially lethal with their exposed shafts.

That type of banana plug is fine for very low voltage circuits, but not for 200v+ DC circuits. Would you be able to buy something like that in a store? No,

You've only got one life, so please don't risk throwing it away by saving a few $, and get some fully shrouded connectors if you build one.

[JohnH]

Cool, I need to make one of these too.

You should!


I'd look at the build picture of Johan's unit in that article. Those are the connector sockets you want. The basic banana plug ones in the bloggers build are potentially lethal with their exposed shafts.

That type of banana plug is fine for very low voltage circuits, but not for 200v+ DC circuits. Would you be able to buy something like that in a store? No,

You've only got one life, so please don't risk throwing it away by saving a few $, and get some fully shrouded connectors if you build one.

Totally agree Simon - if I need them I'll get them from RS, Mouser or somewhere.

I suspect I'll end up building the first version, so may not need the banana plugs. I imagine I'll mostly want to test 6V6, 6L6, EL34, EL84, 12A*7. I'll keep thinking about it while I wait for things to arrive.

I'm contemplating non-battery power options for the meters, but I don't think it's something I'll be using very often so perhaps it isn't saving much waste to just go the battery route.

I also think he's a bit hopeful stating you can build it for under $100 - the 350V caps aren't super cheap, and enclosures, sockets, switches etc add up, especially if you need to add postage. I mean, it is still relatively cheap, but I don't think I'll get it done under $100.

[DrNomis_44]

You should!



Totally agree Simon - if I need them I'll get them from RS, Mouser or somewhere.

I suspect I'll end up building the first version, so may not need the banana plugs. I imagine I'll mostly want to test 6V6, 6L6, EL34, EL84, 12A*7. I'll keep thinking about it while I wait for things to arrive.

I'm contemplating non-battery power options for the meters, but I don't think it's something I'll be using very often so perhaps it isn't saving much waste to just go the battery route.

I also think he's a bit hopeful stating you can build it for under $100 - the 350V caps aren't super cheap, and enclosures, sockets, switches etc add up, especially if you need to add postage. I mean, it is still relatively cheap, but I don't think I'll get it done under $100.

Did you buy those 350V DC caps from Evatco?, and yeah, since I'm into Valve electronics I do need a valve tester of some kind or another, I had a quick read-through of the PDF, it looks easy enough to build, I was thinking of substituting some LCD meters that Jaycar stock for the two multimeters the guy is using in the PDF.

Note: I do understand that the valve tester does use some high-voltage circuitry in it, so I'm well aware of the safety risks.

[JohnH]

I haven't ordered them yet - they were the only caps I didn't have!

I'll probably get them from element 14, as they also have some other things I need. They're about $12 each.

I think I'll screenprint a front panel for the enclosure. I'm teaching a screenprinting class in march, so I could feasibly print it as the demo print and kill two birds with one stone. I'm also tempted to reverse screen my own faceplates for the 18W build at the same time...

[Simon Barden]

A couple of points for consideration.

As it’s test equipment, you really need to use high-quality components so that you get repeatable readings after a few years use. Caps are one of the things you don’t really want to use budget versions of. F&T or similar quality.

And getting the component layout right is as important in a tester as in a valve amp. You don’t want the circuit to induce noise into the valve if you are using it to measure the noise levels of valves.