what european tube tester?

Hallo members!

please help me!

I really need an European tube tester!

All i can find is American ,those don't  test new tubes like ECC808 or EAF801 or ECLL800 etc.

what is the tube tester i need,One that gives me the setings  directly,not to have to go to the American equivalent!

ANY HELP?

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Dear Mr Tsianakas,

I am only familiar with the British ones made by AVO.  The best of these is the VCM163, which is the easiest to use.

The AVO Mk IV and V are also quite good but more difficult to use particularly with high gain valves.

Earlier models than that I cannot recommend as they may not have the required valve bases and also suffer from problems when testing high-slope valves.

You can find thenm on e-Bay from 300 to 600 GB pounds.   

Having repaired a few, I find that the calibration is often in error on testers as the basic meter sensitivity can be wrong and this affects all the calibrations. 

If you only need to test a few types, then a home-built system can be very good as this can use dc rather than ac supplies and can be accurate using digital metering - but it takes a little effort and time! 

Best regards,

Roy 

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Yep, those AVOs already mentioned by Mr Johnson are great.
Highly recommended ! But the magnets inside the meters may have lost up to 40% of their initial field strength... First, I tried to 're-magnetize' the magnets. But that did not work ! Altho I was able to produce several kA in a coil around these. Ok, I'm not a specialist on that...
So, I designed an op amp based current amplifier circuit that drives that current now needed by the 'weak' meter to display f.s.d. when it has 30μA flowing in it's input  - that overcame the problem and afterwards, the whole calibration process (performed according to AVOs original instructions) didn't render any trouble.
These AVOs usually are NOT available over here in Germany (and I will NOT give away any of these I do own) but you'll find them in GB, in Australia and sometimes even in Scandinavia.
---
I became aware that first, some fundamental things should be pointed out. That's why I added this :

Before selecting a certain instrument, we should become aware about what's important to know about a tube's condition and what is negligible.
So, what do we want a tube to do ? We want it to operate as an amplifier... or as a switch, an oscillator or anything like that. In other words, usually, we want it to control the plate current by means of at least one grid. (Sure, there are rectifier tubes, tuning indicators, etc., too, but once having an instrument capable of operating tubes under or quite close to 'in-circuit' conditions, also these can be tested properly.)

We do not primarily want a tube to simply draw a more or less heavy current - if we wanted just that, we simply could install a resistor in it's place. That's cheaper, smaller and is less prone to causing trouble.....
But on the other hand, it has to draw a certain amount of current. Otherwise, it couldn't work - and, especially in output- or other stages, the current through the tube is, in combination with the mutual conductance plus an input signal, quite important to get a certain amount of amplified power into the output.
So there's the mutual conductance, too. Without it, our tube would equal that previously mentioned resistor - it would be worthless for amplification purposes.
If we had (this is impossible...) a tube having full rated mutual conductance but almost no emission, what would happen to the Plate-current-to-grid-voltage characteristic curve ? It would become infinitesimally small; meaning the input signal must be reduced to a fraction to ensure not to face limiting behavior. But that's play of thought only....
You'll agree now : Both, mutual conductance as well as emission, are most important characteristics. The amplification factor is pre-determined by the tube's construction and will not change due to aging. Poor emission will affect the tube's inner resistance - it will rise, while the mutual conductance will be lowered. (These are the three factors found in Mr. Barkhausen's equation.)
In other words : mc and emission can be related to each other. That's why taking an mc OR emission reading only (the static method) already tells a lot about a tube under test.
Since the given mutual conductance figure applies to a certain plate current and the grid voltage belonging to it, the other voltages must be in accordance to the manufacturer's data sheet, too, and one CANNOT measure a mutual conductance without having a tester which can be set up accordingly. Anything else will result in arbitrary values (given by the tester's manufacturer) a tube under test has to meet. You cannot test other tubes than those listed by the tester's manufacturer.

So, most testers which cannot provide voltages, etc. in accordance to the tube manufacturer's given data can be considered almost worthless.
(There are only a few exceptions, like the American TV-7/xx series testers, which can be considered useful for a quick overview when it comes to several small signal types.)

What's unwanted during tube operation ? A tube should not generate inadequate hum or noise. A tube should not develop any internal short, hot or cold. A tube must not draw a grid current reducing the negative bias unless it is gas filled. A tube is not a microphone - especially the grids 1& 2 as well as the cathode must be fixed inside properly (usually by those mica wafers). Finally, the tube should not produce unwanted distortion - it should not add harmonics to a signal fed in when operated as signal amplifier. This is a question of the tube's internal construction and especially the grid, but distortion will also result from an improper grid bias due to gas inside or poor isolation. This poor isolation does occur quite often; at least more often than one would expect. It results from evaporated (and afterwards somewhere else condensed) metal sent out by the cathode. Faulty isolation will not only affect the bias; it also produces noise. Quite often, these faults - isolation, gas, hum, noise, loose grids, etc. - remain hidden within the cold tube. But once it has heated up under real operating conditions, they, all of a sudden, sometimes crop up.
So, any tester should be able to determine faulty isolation even in the 50Meg region. It should be able to supply the grid bias via a 1 Meg resistor while checking emission ( if the bias is lowered and due to that, the plate current heavily rises, the tube is gassy) or check the grid current's direction - electrons coming out of the grid wire are ok; electrons flowing into the grid usually indicate a gassy tube. But often, these checks do not make sense with a tube not really hot !
This is, again, why a tube tester has to be capable of operating tubes (at least, from the 'dc point of view'; without signal) under or quite close to 'in-circuit' conditions (when you'd like to know how it'll behave in your piece of equipment) or under those conditions stated in the tube's data sheet (these usually are the data the tube will be operated at in the equipment); or simulate that by applying half waves dynamically while also loading the tubes - that's what the AVOs do.
This first 'chapter' has been written to enable you, based on the given criteria, to quickly sort out the duds and to decide whether a tester in question will match your needs since there are hundreds of testers on earth not described or even mentioned here.



This is my recommendation :
Do NOT purchase these primitive Funke W16, W18, W19, RPG4.
Do NOT purchase these primitive 'like Funke' GDR- made instruments RPG61, RPG64, RPG70.
Do NOT purchase the Neuberger RP 270 / RP 275.
Do NOT purchase the Euratele or any Tubatest.
Scroll down if you'd like to know why....


Any tube tester should - at least - have controls to precisely adjust the - :

• -- Heater voltage

• -- G1 voltage

• -- Screen voltage(s)

• -- Plate voltage (British : Anode voltage ;-)

and should be able to supply up to - at least - 100mA plate current while the voltage should remain stable.

Any tube tester should be able to determine faulty inter-electrode isolation even in the 50MegΩ Region, applying a voltage between 10...50V while doing that.

More on testers later - got to get some decent night's sleep now....
----------------------------------------------------------------------------------------------------------------------------------
Here's the second chapter :

Dear Mr Erb: Sure, that's true.
I do not know whether this may be far beyond Mr Spiros' needs - but while RM.org has many more users than just him, I consider it conceivable there's someone out there interested in this - or, at least, will read through this ;-)

So, let me continue....
According to my experiences, it does not make too much sense to check a tube's cathode capabilities under random conditions pre-determined by the tube tester maker - but that's exactly what those 'NoGo' testers do ! The Funke 16, 18, 19 do not provide any grid bias other than zero (grid & cathode strapped together) or -2V approx. to check for connection between grid & base prongs. To get the resulting plate current back within limits, Funke also reduces plate and / or screen voltages. This definitely is too far from real operation - and it does not allow measuring anything else like mutual conductance, hum, etc. In addition, the valves do not become hot enough on these testers, so there often are tubes like ECL 86 or ELL 80 appearing good on these testers while inserted in the circuit they should operate in, they develop inter-electrode shorts or show floating grid bias due to residual gas.
The foregoing also applies to the other instruments mentioned above, while several of these are even worse - some do operate the tube as a rectifier only, strapping all the grids plus plate together. Applying something around 30VAC, they simply measure the resulting current. This may damage several small-signal tubes ! Neuberger RP 270, Euratele, Tubatest, Kiesewetter Vollnetz and a lot of others do operate that way !
And, you cannot check any tuning indicator's target on these. But, that's something we'd like to do very often, don't we ??
Sooner or later, you'll face another serious problem while using these primitive testers : While the test data are arbitrary, you cannot check any tube you don't have test data for already given by the tester's manufacturer ! You cannot set up the tester in a way making it supplying exactly those voltages, etc. given in a tube's data sheet. But that's what you need testing unusual types or for comparison purposes.

The AVOs use a sophisticated AC voltage testing method. This results in a dc-like tube operation which allows to check emission as well as mutual conductance plus isolation, giving real values that can be compared to any tube data sheet. So, these AVOs could be kept small (50cm) lightweight (15kg approx.) and are easy as well as fast to use. You do not need anything else but the tube, your AVO and a tube data table containing the type you'd like to test. Due to well designed transformers, you do not need an array of meters monitoring each voltage - but you'll have to adjust the AVOs for the mains voltage currently present. The AVOs do contain one or too meters only; displaying the different results for emission, isolation, M.C., etc. on the same instrument, one value after another. AVO's method checking rectifier tubes is the best I've ever seen ! They really load a 'lytic, paralleled by an adjustable load. However, I wouldn't consider the AVO VCMs laboratory grade instruments, but providing results you can trust in. If you do have a pen plus a sheet of paper, these also enable you to draw usual characteristic curves. (You CANNOT precisely check low-my power triodes like 6080/ ECC230, AD1, 2A3, 6B4, etc. on these !)

Now, on those -still portable- instruments operating the respective tube under dc conditions while they can be set up for almost any tube just by adjusting those electrode voltages given by the tube manufacturer.  There are the Funke W17 and W20; also Neuberger RPM 370 and 370. The W17 is too old; it's a pre-WW2 instrument. It looks VERY nice, but if you aren't into collecting test gear, forget about it. The same applies to Neuberger's pre-WW2 Instruments named WE2... / WE3...
20, 370 as well as 375 can be considered basically multi-output power supplies which have an array of meters plus lots of switches and sockets added. Heater, g1, screen 1, screen  2 and plate can be adjusted to almost any desired value. Limits are around 500VDC / 200mA DC (plate supply). After getting one ,there's more or less to do getting it back into useful condition - recalibration of the meters built in ( not primarily the 'AVO-problem' ; more the shunting resistors, etc.), replacing several 'lytics, plus replacing usually two or even more of the power pots (rheostats) are the most common tasks. These are rated 25 ... 100 Watts; so these are quite expensive.
These do allow virtually any static measurement as well as adding a plate load, a cathode load, etc. Sure these also enable you to draw usual characteristic curves. And, you CAN precisely check low-my power triodes like 6080/ ECC230, AD1, 2A3, 6B4, etc. on these. But you'll permanently have to monitor and, sometimes, re-adjust all the voltages. In other words, measuring a mutual conductance will take some time using these instruments.--- I'm not satisfied with the W20's isolation checking method; the voltage is too low, so the meter will not display faults above 2Meg . I'm also not satisfied with the 370's isolation checking method; the voltage is too high, and the meter isn't enough sensitive,so the meter will not display faults above 2Meg, too, while damaging high-slope frame grid tubes isn't always impossible.
The 375's isolation check seems to be fine; but while mine is still waiting for overhaul, I can't definitely tell yet ;-) Otherwise, the 375 is a re-issued 370, containing  more stable supplies, larger meters, modern tube sockets (not the early ones any more!), an improved inner circuit, a more up-to-date appearance, etc.

Now, it's too late again - let me talk about those more sophisticated instruments in a few days..... (the impressive 180kg - Neuberger RMP 400, the H&B 55 / 55a modular system, and others....)

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Dear Spiros
First we should have to know what is your intension. Depending on that you can read judge the different answers you will get on this question. A reader can learn quite a lot from Roy's answer and from the answer of Mr. Hasselmeier. They all have their point but for you that may just be the points or not - depending on your needs on your money and on the availability.

There are good reasons why some build a pocket valve tester on their own - like I did for instance. There are several principles for that one - for instance just bringing two third of the heater voltage, comparing the drop down of plate current in comparison to full heater voltage. This shows you only the state of the "filament's emission capacity" but this is also what you most often need to know. The other test does your receiver ...

My second tube tester was a pre made meter from a tube collector friends fabrication and since I'm a collector I bought testers like Taylor 45, Euratele (very cheap) Funke, Neuberger etc. There are reasons why they have been built and used so much and many times. I should not forget (but did) that when I was about 12 years old or so I could get a Philips Cartomatic (1936) from a radio repair shop because they had newer ones.

Please state what you want to do with it and then you get "hand made answers" for you. Now you have some answers on the cream of tube testers only few could afford - also to use ... But maybe you want just that.

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Hello John !
Same thing over here : Got two Mk IV, one giving erroneous results first due to wrong calibration caused by the misleading meter - and an other one that could easily brought back within specs just by following the steps given in AVO's calibration manual. AVO itself has published some information about the different meters built in and the fact that there are some which provide a stable sensitivity while others don't. Over the years, they used different alloys - that'll be the key.....

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Dear All,

Mk IVs must go in pairs!  I have the exactly same problem with two - although one had rust inside the movement and I probably weakened it (further?) by taking apart and cleaning the magnetic gap around the moving coil.  

Let this not put off the original questioner, however, the AVO machines are very good, reliable instruments for regular fast routine testing of a wide range of valves.   Because the VCM163 uses audio frequency injection to determine gain, it is easier than the backing-off technique on the earlier machines where one has to follow the drift of the anode current to get an mA/V reading. 

However there are other considerations, for example noise, both at audio and radio frequencies. For audio I use dc regulated supplies and a dedicated circuit followed by a HP spectrum analyser. The heater being ac or dc supplied to sort out the genuine valve noise from heater-injected hum.   RF noise measurement is again possible with such a set-up but probably best by selection in the equipment in use.  

As everyone has said it all depends on WHAT one needs to test!

Best regards.

Roy

 

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Greetings Spiro and others.

 As I read Spiro's request, he wishes to test fairly "modern" tubes i.e. EAF801, ELL80, ECC808, etc. yes- The newer ECLL800 also...
If simple "dynamic" emission testing is acceptable, and if the  amount of money for investing in a tube tester is a concern,  may I suggest the USA-produced Jackson model 648S tube tester.
 Together with the very comprehensive testing data book specified for the models 648 which is  currently being offered via the internet, this device will certainly provide a basic test of all the later European types mentioned, plus many, many more.

  Certainly, "Stahlröhren,"  "Aussenkontakt" and older European types would not be so readily tested with such a device, but for the later tubes of European design, this Jackson tester model is certainly a good value for the  money spent, in my own opinion. 

 Happy Holidays!
 Dennis Daly

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Hi All

There is also the CT160 valve tester - this has all the bases that you would want, and is usually a bit cheaper than the AVO VCMs.

It uses AC to test the valves, using the same principle as the VCMs.

A common fault on it that will make it even cheaper, is a burnt-out  Set Vg pot (RV2).  This is a special wirewound item that has three sections of the track divided into different values - 1.25k, 2.5k and 5.25k. 

I have devised a way to repair these.

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Hello Gentlemen,

I have been very pleased with the capabilities of my Hickok 752A for the last  11 years. I  have created  several adapters which allow me to test  (with some degree of  accuracy) even the  early European tubes with the European-only bases. . . . . . . and a 6-pin (4-2) adapter to allow me to test some RV12P2000 Wehrmacht tubes for my 1946 Siemens & Halske Marloffstein receiver.

The authorized Hickok FOREIGN TUBE TYPES  supplementary Test Data for the Model 752 and 752A testers  (pub. nr 3200-198)  provides 12 full pages of test data for tubes  ranging from 1AJ4 through the numerical 8319; and then identifies the test capability of the European tubes from AZ41 through ZD152.

With the added Grid B test switch and the added Gm2 test button, the procedure for testing Dual-section tubes is simplified.

There is another Hickok publication  Nr. 3200-130 (prior to the 3200-198) which provides test data for even earlier tubes. I am not certain if there is a publication which lists the last of the European tubes produced after 1968.

Respectfully,
Robert

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Hello again!

 Of course, this very nice web site may be standard knowledge to those whose language is primarily  that of German, but it shows  another alternative to testing the older European-exclusive tubes by means of relative mutual conductance if one already owns, or is willing to purchase (rather expensive)- an easily found  U.S. military TV-7 tube tester of Hickok design-- and to make the effort to build the adapter box as shown in the article.
 Note that a considerable quantity of test data for use with this adapter box and TV-7 has been created and published for sharing with others.

TV-7

  I have home-produced  some individual adapters for Rimlock, Aussenkontakt, and Stahlröhren  base types for use with my Hickok series 600/ 600A/800A testers .
 However, I'm only beginning the development thus far  for only a very few types of the G8A, P8A basing styles.
 Test data for many common Rimlock types are already listed in approved Hickok test data lists including for these simpler, compact models I listed.

 Also,here is  another low-cost option when wanting a basic emissions testing capability for many of the more modern and common European (7 pin, 9 pin Noval and Rimlock) types...
 The "Precision" brand 600, 900 series 0r 10-** series tube testers offer a fair amount of test data for the European type designations.
  Limited data for testing the older Stahlrörhen base types EL11and EL12 (among others) is also listed, but I have so far not found any information regarding the required adapters, other than the "upgrade" adapter for the Noval types not present on only the oldest of the Precision models.
 Fabricating  proper adapters for use with this brand of tester for testing tubes having the P8A, G8A, -P2000 basing styles  would likely be the task of the owner, I am thinking:-

Thanks to Chris' Old Radios for making this data available.

users.iglide.net/hworth/radio/precision.html

 Please note the European type- designated tube testing data is usually located toward the back (rear) of the various listings.
I think quite a lot of the more common types are shown, considering the data was produced for a tube tester brand that was primarily intended for the North American market.

 These are two more economical options for the hobbyist  that will allow some basic testing of a number of the more common types of European-designed or internationally-designated  types of tubes.

 I only dream of finding a nice Funke or AVO for adding to my Christmas joy this year..:-

 Best Regards,
 Dennis Daly

 

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Hello tube friends,

another manufacturer of high quality tube testers was Neuberger in munich, Germany. They manufactured a serie with tube testers, RPM370 and RPM375 (RMP400)  working with the static way of measurement. With other words, these testers works excactly similar like the ones in the tube manufacturing companies. The testing dates are published in many good data books, so you need no special tables to check tubes.
The named Neubergers have a good short test circuit with a glow lamp, several power supplies for heating voltage, two positive and two negative grid and a anode voltage. All voltages can be controlled with own instruments. A crossbar circuit switch allows a unlimited varability of possibilities. Punched card makes the tests very easy. 18 sockets are buildt in.
These testers are so flexible, that you can rebuild circuit simulations in low frequency area, for example: Testing magic eyes under working conditions or measuring the characteristics curves for a variable mu tube.
Dynamic testing is possible, but you need a external AC supply and a output transformer with a low frequency multimeter. But you can reach the result also with two static measuring points.

Unfortunately are this testers about 40...50 years old and very expensive. I think its a better way to build it new with modern parts and more comfort.
So you need following (independent) parts:
Socket boxes
Heating power supply
Positive  grids voltages supply
Negative grids voltages supply
Anode voltage supply
Main switch unit
Short tester
and a few good data books.

Happy christmas and a very good new year,  H.-T. Schmidt

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We have seen here many answers. What is still missing is an overview about different methods used for tube measuring equipment.

Kurt Schmid has published a wonderful article about the very good AVO V.C.M 163 which I can recommend for reading. I have moved it to the model page so that interested people can learn about the measuring principle of it.

I will ask Kurt Schmid (because he is highly methodical) if he could write an article about the different methods used for tube measuring equipment in general, beginning with simple methods like multimeter or even ohmmeter only up to the most advanced electronic and graphical methods which are possible since some time with computers. Measuring principles of tube testers begin with continuity testers, simple tube checkers (see the very old Hoyt 100) with an instruction text), real emission testers (cathode or plate Eico 635), with or without short circuit test, parametrical testers (DC = W20, RPG375, AC = AVO), mutual conductance testers (transductance testers, Hickok 539c, WT-110A), dynamic conductance testers (Jackson 648), oscilloscope tube curve tracer (Tektronix 570 or some designed by members - really very good ones!).

Good would be to have some examples for each principle including price ranges (perhaps found on those models as the stored collecting prices). An other important parameter is the skill needed to operate a given tool or set (for instances set of cards instead of having to know many values, Hickok 123A). Then also the age (sockets possible) will be an other parameter - as we have learned above. Some thoughts about mixer or very high frequency applications where some times the set only can tell if the tube can do the job there or not would also be a topic. Just everything somebody has to know if he/she is confronted with the wish to have the possibility to test tubes.

This is surely not an easy task and will perhaps involve quite some time. Therefore it would be great if Kurt Schmid can tell us if he fancies such or not. In the latter case maybe somebody else could step in - anyway, for any help he would surely be glad for. Members who have built their own system can tell him so that he can point out such possibilities. When such article has been made, we will link it here too.

Too often we forget how few tubes we have to test and what really matters then ...

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