computer tube tester

[yourownfree]

I would like to make a computer tube tester to test all functions, trans-conductance,Ip, and even graph load lines etc. The software can even be written as license free and allow for more development.
I started a thread about another subject that turned into talk about a computer tube tester so I am starting a thread just on this subject. The end result hopefully will be someone has already done this and save us a few years on our life.

I can visualize how I would put one together. I saw the RAT circuit and seems to be ok. Maybe use that circuit and add to it. Need a data base of tubes in your program with input to add more. That way it knows what switching to make automatically when you select a tube. An approach to change the voltages could be realized by simple switching using CD4066's or similar scheme controlled by the computer of course. Switching to each resistor a part of a regulated adjustable power supply. Selection of the proper resistor sets the adjustment on the regulator. That is to say each resistor you select or combination of is the same as turning a dial to dial the voltage in. Then program the computer to take voltage readings, change voltage and go for it again. Even use the computer audio to inject the signal in the tube at varying levels and input the response. Now for switching the tube configurations. I think, I am going to look at high side load switching a mosfet, for the B+. More of course can be done and it never works the way one wants its too and always have to tweak on it to get it right. At least for me anyway.Maybe these ideas can work. I know there is such a thing on the market I saw it. Its always fun and challenging to make one to make one. What's your thought on a computer based tube tester and your ideas?

[planet10]

I've imagined one of these... i'd like to encourage you... if you point me at the posts in the other thread, i can move them here for you.

dave

[aardvarkash10]

take a look at Yves plotter if you need inspiration... or perhaps collaboration.

[boywonder]

Originally Posted by planet10

if you point me at the posts in the other thread, i can move them here for you.

dave

Dave: They are here:

having trouble calculating transconductance

[c2cthomas]

Here is another similar project that is worth looking over for ideas. A Microprocessor Controlled Vacuum Tube (and other) Curve Tracer

This should be a nice project to play around with - might get me back into tubes after 40 some odd years.

[planet10]

Originally Posted by boywonder

Dave: They are here:

having trouble calculating transconductance

I was hoping someone would suggest the post #s that were relevant.

dave

[RE 604]

Hello ,

RoeTest - Röhrenprüfgerät Röhrenmessgerät

and here the description in the german forum :

Computer-Roe-Pruef-und-Messgeraet, von Helmut Weigl

Kind regards , Alexander .

[nicoverduin]

Originally Posted by RE 604

Hello ,

RoeTest - Röhrenprüfgerät Röhrenmessgerät

and here the description in the german forum :

Computer-Roe-Pruef-und-Messgeraet, von Helmut Weigl

Kind regards , Alexander .

This is a great site and very inspiring...

[yourownfree]

I like the people on this forum, most interesting. I have been to other forums where there is a one man band so to speak, a lot of people participating but only one person who has nothing else to do, answers the questions and makes you feel like you don't know stink. Well I don't know stink, but at the same time I finally got him one day and proved him wrong. What a waste of time and effort and I ended up being just as bad as him by getting back at him. I cant live like that! I like this forum because I am not seeing that here, and I don't have to feel intimidated. I see people who are willing to share their knowledge to others and I don't have to feel the need to try and protect my feelings and thoughts or try to lash back at someone to save myself from ridicule. Don't get me wrong. I like to hear all sides of the story and a better way to do things or different ways to do things. To all of you I thank you. I like the enjoyment of all the articles and the learning all the post provides. Keeps my mind busy. Just seems like a great group of people here, definitely in a higher class, and of good nature.

Dang! did you see all the relays in the picture? about 70 relays. The guy really did alot of work on this project. I don't know if I need one that bad. I like the program though. I am going to look at that a little more closer and see if it is easy to hook up to with other circuits. I did have to drop the url in Google translate to see, since I don't understand the language. Just alot of work went into that machine. you have to eat and sleep it in order to get done by Christmas. I still think relays are too costly and bulky. I think if a guy came up with a good circuit, just send it to a pc board making place and save some time making a board. I have read some on using the midi interface, then I also read it was not accurate. I don't have enough data on that yet to know for a surety. I suppose for tube testing it doesn't have to be that precise. Does one have to have precision or is just some simple tests good enough for testing tubes. You know the basics. I guess if you wanted to know if the tube starts oscillating you could just simply have a frequency counter sniff that out. What are the basic tests you would consider as being enough? of course one could add to it later. Is just testing the emission, Gm, Ip, Rp, with choice of voltages at your disposal for plate, screen and grid enough? What about a load of some kind? Ac and Dc selection of filament and variable?

[smoking-amp]

I think that one should simplify first to make progress on such a complicated project. The pin switching network is almost frivolous, but very complex with many HV issues. Just put bananna or pin jacks on the unit case labeled cathode, g1, g2, g3, plate (grid stoppers, ferrite beads etc inside the unit). Then make up some general 7,9 pin, octal, .... sockets with bananna or pin plugs on each pin. (use short leads, the pin plugs are easier to insert/ remove than bananna ones) You have to consult the tube base diagram each time, but is quite adequate for testing a box of similar tubes.

Then for the next step up in convenience, one can make sockets per the common tube base types, with the pin plugs mounted on an insulating strip that plugs in to the jacks correctly.

For plate resistors, one can avoid a collection of switched-in power resistors by using a programmable power resistor:
EDN PDF (bottom article)

Power supplies are available off the shelf with programming ports that can connect to the PC. I use some Xantrex units with serial ports. (GPIB ports are more common than the RS-232 ones, but are more complicated to get interfacing set up to the PC and to use with cheap software) (I don't have software designed yet to use them, but I plan on using Visual Basic).

In the mean time (probably my main excuse for not getting the above mentioned programming done yet), I use a Tektronix 576 (or 577) curve tracer that has been modified to do tube curve tracing. I have the Xantrex power units (for the above project) rigged to supply g2 voltages (separate for each test port - 1 and 2), and separate filament supplies too. Just have to toggle the selector switch to display curves for either tube, which can be totally different tube types if desired.

The curve tracer is a giant leap over any tube tester, and for a similar price too, and can match tubes over their whole characteristic. But a PC automated unit, will clearly be the ultimate, allowing further linearity analysis and storage and printouts.

Don