German "RoeTester" (Valve Tester Design)

[Chris55000]

Hi!

Has anyone actually ordered the parts or got a quotation for the German Design "Roe Tester?"

A number of comments on the "CT160 Auctions" thread all said that it's expensive, but how much approximately?

If the "Roe Tester" is worth considering, which items would I need to buy that's absolutely essential – would this be the PCB set and the CD ROM + Micro?

Would the Sussex be cheaper than this to build?

Chris Williams

[Chris55000]

PS!

Mods,

I've just been wondering if this was better placed in the "Homebrew" section or "General Vintage Technology" sections, can you move as appropriate please?

Chris Williams

[Craig Sawyers]

I've pondered building the Roetester from time to time. I got a quote maybe 8 years ago for the specialized bits - the boards, CD rom and micro, and the two main custom transformers. If I recall, that was a couple of hundred quid, probably more now. Plus all the bits, of which there are umpteen relays. Then the box, valve panel and other gubbins. I reckoned that the total would be ~£1k - which was too hot for my pocket.

But it really is fully featured, and can supply currents and voltages that are outside the scope of most if not all valve testers. Very tempting, but not cheap.

The Sussex would be *much* cheaper. As would https://www.dos4ever.com/uTracer3/uTracer3_pag0.html

Craig

[Craig Sawyers]

Found the prices for the bought bits http://roehrentest.de/FAQs.html

So an estimated cost including all the bits of Euro 964 plus valve bases, connectors etc. So my initial guesstimate of a grand is not far wrong.

Craig

[David Simpson]

It was Martin Forsberg in Sweden who briefed me on the RoeTest. As he had built one. Manufactured in Germany I believe, and comes in a kit form of hardware & software. Must be about 2 or 3 years ago when I checked the prices, and the basic kit was about £1200. I think the whole kit with add-ons & mods was about £2000.
A lot of dosh, but Martin's software Gm graphs of a couple of 6AU5's we compared for standardisation were spot-on.
For those folk with "up to speed" knowledge of 21st century computer based electronics, and heavily into valve testing & valve circuitry design - I guess this machine is just for you. If you can afford it, that is.
I'm, as I've often said of late,just a 1960's analogue guy. And, of late, have been encouraging folk to "Re-purpose" vintage test equipment into DC valve testers, Curve Tracers, etc. Buts thats not to say that I dont appreciate the advantages of modern hardware/software design.
Mind you, just for the challenge & experience - wouldn't mind getting my hands on an old Tektronix 570, even if it took ages to do up.

Regards, David

[Craig Sawyers]

Ah - have you looked at the price that a 570 gets? You're talking £3k. It has rarity value (most got scrapped), well heeled audiophiles got wind of them - particularly in Japan - and that ratcheted the price up.

In Stan Griffith's book "Oscilloscopes - selecting and restoring a classic", which is the bible of classic era Tektronix oscilloscopes, published in 1992. The 570, because valves had gone out of fashion, is listed at typically $400. With the dollar rate at that time it corresponds to £200! If only.

There are legends of people finding them at radio rallies in a pile of stuff and picking one up for a tenner. But that might be apocryphal.

Craig

[chriswood1900]

One thought about anything that relies on digital software is that it will only work as long as the necessary software and operating system is available and supported otherwise you are into keeping old computers running just for your piece of test equipment. I already have that problem and can assure you David S's analogue world is much easier!!
This is not to decry some excellent test equipment just a fact of life. A computer based valve tester is less likely to still be capable of working in 40-50 years unlike an AVO.

[Dekatron]

Yes, as David says I own this tester, I actually own two of them, an older V6.2 that was upgraded to a V8 and a later V9 upgraded to a V9.X.

I hope that you can get some good information and questions below.

I think that you first have to decide why you want one of the more modern testers, some questions you can ask yourself are:

1. Do I want nice curves on a paper or saved as a file to look at? It can be done with DC-power supplies and an Excel spreadsheet but will take more time manually. Then you also need a computer too hook it up to and possibly a printer too.

2. Why do I want the full curves? To weed out valves that perform poorly at some spot along the curves or do you want to experiment with valves outside of their known characteristics or what?

3. Should I invest in a few nice high voltage DC power supplies, which can be used for other purposes, or should I invest in a standalone valve tester without the need for an external computer like the Sussex, or even a cheaper one like the uTracer?

4. Do I like to build stuff and set it up to fully working conditions (like I do too) apart from getting a valve tester?

5. Am I going to use it to sell tested valves and proove that the valve has been properly tested?

6. Do I know enough about valves that I can say that a valve tested on a Roetest is properly (better?) tested than if it was tested on an AVO, a Sussex or a uTracer or with DC-power supplies?

There are some things with the Roetest that not all of its users experience that I have come across over the years that I have told the designer about, some of which he has changed in its design, but there are still other areas that still need changing in its design to become a better valvetester. As with most home built designs there are ways of blowing it up and there are ways to get it to work in unintended ways, either damaging itself or the valve you are testing.

Simple things like adherence to datasheet specifications for components has not been done properly, and that is one of the things I have tried to point out to the designer, even with help from the manufacturers of the components, which he still hasn't accepted nor changed - I just hope that he will do so in the future to get a better design. It is a home-designed device and even though the designer is willing to discuss problems with you it takes time to get improvements/changes implemented, if at all. I often compare the Roetest to the uTracer, the uTracer with all of its design decisions described in full at Ronalds webpage www.dos4ever.com is a valve tester that I really appreciate (I have a uTracer too of course). There is also a newer uTracer V6 here: https://www.dos4ever.com/uTracerlog6/tubetester6.html apart from the earlier version uTracer V3+ here: https://www.dos4ever.com/uTracer3/uTracer3_pag0.html .

I needed a valve tester to better understand valves but I also wanted to understand how AVO valve testers worked with their AC-design and I also wanted to compare DC-testers with AC-testers. Then I also had an interest in how to replace valves with semiconductors in some designs, like the Fetrons or Tubesters do, and I have also been working on a semiconductor based calibration valve that can be used both on DC-testers and AC-testers. I do have a design for a calibration valve that works but I haven't quite figured out all of the maths involved yet and I still haven't figured out the best components and their values to use for best performance so I am not fully satisfied with its performance.

One thing I could do with the Roetest is to set it up to automatically test the same valve over and over again, and my semiconductor design, for a whole week (!). Testing an ECC81, 82, 83 & 88 valve for a week, where each test took some 3 minutes, meant that I stored over 3000 tests each week, the semiconductor design could store a test every 20 seconds, this as I didn't need to wait for a warm-up time, which meant over 30.000 tests per week. That amounted to a lot of data and wouldn't have been possible on any other tester that I know of.

What did I learn from this you might ask, well, I might let you know the full story some time in the future if I ever finish my semiconductor design, or if I decided to leave it unfinished - but I can let you know one thing that took me some time to realize: The sun affects both the valve and semiconductor design during the tests as well as the Roetest itself as it heats them up during the day. I finally understood this when I pulled down the blinds in my hobby room and the measurements changed, removing the blinds again changed the measurements yet again. So my tests had been runing for a week with no blinds so the sun had affected the measurements every day, which showed a change when the sun came up or went down, cloudy days would also affect it, but I didn't check what the weather had been during my tests, I was just satisfied that I had understood the reason for the changes.

So as I wrote above I own both the Roetest and the uTracer plus a bunch of different AVO testers.

[Matthew kane]

An ex military radio and broadcast engineer I used to keep in touch with years back owned one of the earlier versions of the Roetest as well as a heap of AVO VCM's, Neuberger testers, AT-1000 and last he was raving about the Bitmatic tester (suped up Hickok/Western Electric KS-15874-L2 cardmatic tester that has been computerised).

Testers like the roetest, utracer, etracer, 570 with valve attachment and the Bitmatic testers fall under true analysers, not ideal for quick testing tubes. These testers take a long time to test a tube and these are made for people who want to understand and observe the operating characteristics and elements of the tubes you test.

Last time I checked the price was around $1500 AUD for the base parts for the Roetest.

[Petedox]

Originally Posted by Matthew kane

Testers like the roetest, utracer, etracer, 570 with valve attachment and the Bitmatic testers fall under true analysers, not ideal for quick testing tubes. These testers take a long time to test a tube and these are made for people who want to understand and observe the operating characteristics and elements of the tubes you test.

Agreed, however the utracer does have a quick test function (which I use most of the time).

[Petedox]

Originally Posted by Craig Sawyers

The Sussex would be *much* cheaper. As would https://www.dos4ever.com/uTracer3/uTracer3_pag0.html
Craig

Yes, the final cost for my utracer was around £250 inc. wooden box from eBay. Pretty easy to put together with excellent support from Ronald Dekker, his website and User group.

[Chris55000]

Hi!

Thanks to everyone for their helpful contributions on this, I'll buy the PCB set and CD for now later this month or next month's payday and take it forward from there as funds and time permit!

Chris Williams

[Dekatron]

If you are going to build the Roetest I can recommend you to buy the two torodial transformers from the seller instead of just the big one, the small transformers are mounted to tight according to the manufacturer of those transformers so they give of too much heat and also has a small effect on each other both by spreading the heat and also in a magnetic field way.

I can also recommend you to buy the case and the pre-drilled heat sink - that will make it a a lot easier to build the tester.

One more thing that I can recommend that you do if you are going to use more than one adapter to test tubes, like for testing Nixies or other tubes that need an extra box with breakout connectors or extra anode/grid resistors, is that you rotate the contact for the adapters sideways like I did here: http://www.roehrentest.de/NB Forsberg Martin V9.html - that way you get a longer area for placing adapters in series.

What you also see in those photos is that I built an extra internal power supply with a few more transformers which made it possible to have an external regulated +12V line instead of the internal unregulated "12V" line that takes its power from the relays - accidentally shorting the original unregulated output means that all realys also lose power. I also added a separate 12V supply for the fans that I mounted above the heatsink which were necessary for the soak tests that I performed, otherwise the Roetest would shut down.

I also added a few tube pin straighteners to the top panel so I would always have those at hand.

I hope I still have the files available for the fan mounting as well as the extra power supply, but they might be lost since I had an SSD crash where those files were stored and I am not sure I have a backup of those. If you are interested when you have built your roetest you can come back to me and I'll search for them then. Since I did build the RoeTest with the small transformers, the extra torodial transformer wasn't available then, only after I had pointed out the advantages to the designer my extra power supply might not fit heightwise with the toridial transformer with the original case sold by the designer.