To my point of view Neuberger RPM 400, but I wasn't enough lucky to take one few years ago 
Now I have to be satisfied with RPM 370 and few other testers, among them I-177B for transconduntance and one small Italian testers when I'm not in the mood to take 30 kg's of iron with me.
www.tubes.rs/Tubes/Testers/TubeTesters.htm
Still looking for 400 ...
Now I have to be satisfied with RPM 370 and few other testers, among them I-177B for transconduntance and one small Italian testers when I'm not in the mood to take 30 kg's of iron with me
.www.tubes.rs/Tubes/Testers/TubeTesters.htm
Still looking for 400 ...
Hi all
I’m new on this forum, just interest if any of people who made a RAT tester still monitoring this thread?
I’ve notice this troubles with RAT tester:
- twice blowing TL072 chip in "true RMS meter" part - don’t know why, probably caused by shorted valve under the test.
Except this, "true RMS meter" works fine.
- like "amadeusMozart" suggest – trouble with g1 goes to positive respect to cathode, even with low power tube
I’ve found reason why this occur extremely in my case (almost to 100V positive), cure this, but this still occur in first start up period.
Probably this is because at start up some capacitors need time to be brought up, or grid current to happen.
I am worried because of that; don’t know can this be harmful for tube under the test.
- I have notice some differences in original Steve Bench schematic diagram, and followed text on his page, anyone else?
But design is really simple and easy to build anyone.
Did any of other diy-er experienced these troubles?
I’m new on this forum, just interest if any of people who made a RAT tester still monitoring this thread?
I’ve notice this troubles with RAT tester:
- twice blowing TL072 chip in "true RMS meter" part - don’t know why, probably caused by shorted valve under the test.
Except this, "true RMS meter" works fine.
- like "amadeusMozart" suggest – trouble with g1 goes to positive respect to cathode, even with low power tube
I’ve found reason why this occur extremely in my case (almost to 100V positive), cure this, but this still occur in first start up period.
Probably this is because at start up some capacitors need time to be brought up, or grid current to happen.
I am worried because of that; don’t know can this be harmful for tube under the test.
- I have notice some differences in original Steve Bench schematic diagram, and followed text on his page, anyone else?
But design is really simple and easy to build anyone.
Did any of other diy-er experienced these troubles?
Personally I think building your own tube tester/analyzer is the way to go nowadays....Make yourself some variable regulated voltage sources and use a bunch of digital meters and your set...
The old Hickoks are basically all the same inside..the 83 tube and the 5Y3 tube...the whole balanced system is great on paper but in reality has too many issues...the dual ganged pot that needs to have perfect tracking halves, don't hold your breath....the transformer really need to be bi-filar wound to have better balance...and a list a mile long of all the sources of error...I admit the look of the military testers are awsome and nostalgic...but the TV-2 with that QUALITY meter is total nonsense...
I usually replace that meter with umhos meter.. Hickoks are OK after lots of mods to correct the faults...by then you could have built a better tester..and for what...at test at 125V and then interpolated from the standard boogie is not way of testing...
The Triplett 3444 is more on the right track but still has some issues... The 250V Plate and 250V Screen option is nice idea but lacks any voltage regulation and the plate and screen share the same 250V node...not good..The screen voltage is also derived from a 10K 10K voltage divider from the plate supply on some of the settings...not well thought out...since any screen current will make for some serious errors..
I usually modify the 3444 to have a voltage doubler by adding another cap and diodes in the power supply...then use 2 small FETs for seperate voltage regulaton of the plate and screen....the selector switch for voltage still works the same...since it will change the reference voltages for the two regulators...
Keep in mind that CATHODE current is not PLATE current.... Cathode current is more popular with some testers....some tubes have serious amounts of screen current that sum with the plate current ...many EL34 tubes can idle at 40mA at the plate and have anywhere from 3mA to 8mA screen current...
The golden rule to measureing transconductance is to remember this is a partial differential Equation...meaning that although you have change in plate current over change in grid voltage , you MUST have all other voltages CONSTANT, meaning REGULATED...or else the gm reading will be eronious...
This leaves very little list of testers that are usefull....
Chris
The old Hickoks are basically all the same inside..the 83 tube and the 5Y3 tube...the whole balanced system is great on paper but in reality has too many issues...the dual ganged pot that needs to have perfect tracking halves, don't hold your breath....the transformer really need to be bi-filar wound to have better balance...and a list a mile long of all the sources of error...I admit the look of the military testers are awsome and nostalgic...but the TV-2 with that QUALITY meter is total nonsense...
I usually replace that meter with umhos meter.. Hickoks are OK after lots of mods to correct the faults...by then you could have built a better tester..and for what...at test at 125V and then interpolated from the standard boogie is not way of testing...
The Triplett 3444 is more on the right track but still has some issues... The 250V Plate and 250V Screen option is nice idea but lacks any voltage regulation and the plate and screen share the same 250V node...not good..The screen voltage is also derived from a 10K 10K voltage divider from the plate supply on some of the settings...not well thought out...since any screen current will make for some serious errors..
I usually modify the 3444 to have a voltage doubler by adding another cap and diodes in the power supply...then use 2 small FETs for seperate voltage regulaton of the plate and screen....the selector switch for voltage still works the same...since it will change the reference voltages for the two regulators...
Keep in mind that CATHODE current is not PLATE current.... Cathode current is more popular with some testers....some tubes have serious amounts of screen current that sum with the plate current ...many EL34 tubes can idle at 40mA at the plate and have anywhere from 3mA to 8mA screen current...
The golden rule to measureing transconductance is to remember this is a partial differential Equation...meaning that although you have change in plate current over change in grid voltage , you MUST have all other voltages CONSTANT, meaning REGULATED...or else the gm reading will be eronious...
This leaves very little list of testers that are usefull....
Chris
Russian L3-3 Tester
I would like to vote for Russian L3-3 tube tester. L3-3 allow test emission, transconductance (using Sergeev's topology), leakage and reverse grid current of almost any commodity tube. Its quite cumbersome to use, at least for the first moment (mostly because of scale with relative, not absolute values), but it does its job very well.
It uses as much as 3 regulated stabilized voltage power supplies, and DC filament for small signal tubes.
I would like to vote for Russian L3-3 tube tester. L3-3 allow test emission, transconductance (using Sergeev's topology), leakage and reverse grid current of almost any commodity tube. Its quite cumbersome to use, at least for the first moment (mostly because of scale with relative, not absolute values), but it does its job very well.
It uses as much as 3 regulated stabilized voltage power supplies, and DC filament for small signal tubes.
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There are manuals in English and German floating around net, so nothing to worry about.
Hi LinuksGuru,
Not only that, but someone who is familiar with different tube testers could figure it out.
Like the old TV-2U I have, someone just starting out can destroy tubes easily when you have a set up that is more like an application circuit. Honestly, something like a Hickok or a Stark (Canadian version) would be far more useful. That and faster to set up.
I'm thinking of taking a lunched tube tester and rebuilding it into a modern type with a micro-controller and a sine wave oscillator. The parts are useless otherwise, and the transformer is the valuable part.
Getting back to the original question, "which tube tester is the best?", it would depend greatly on what you want out of it as far as numbers or good / bad. It also depends on what tubes you will be testing. The older testers most of us have were designed to be generalist machines, capable of testing most anything out there. That was a concern for the shop spending all that money after all. It would also help if the tube was tested for transconductance instead of straight emission like the less expensive testers did. Of course, there really is not test as good as measuring the tube in question in the circuit designed for it.
-Chris
Not only that, but someone who is familiar with different tube testers could figure it out.
Like the old TV-2U I have, someone just starting out can destroy tubes easily when you have a set up that is more like an application circuit. Honestly, something like a Hickok or a Stark (Canadian version) would be far more useful. That and faster to set up.
I'm thinking of taking a lunched tube tester and rebuilding it into a modern type with a micro-controller and a sine wave oscillator. The parts are useless otherwise, and the transformer is the valuable part.
Getting back to the original question, "which tube tester is the best?", it would depend greatly on what you want out of it as far as numbers or good / bad. It also depends on what tubes you will be testing. The older testers most of us have were designed to be generalist machines, capable of testing most anything out there. That was a concern for the shop spending all that money after all. It would also help if the tube was tested for transconductance instead of straight emission like the less expensive testers did. Of course, there really is not test as good as measuring the tube in question in the circuit designed for it.
-Chris
I have situation with my diy-tester that in first 10 seconds at startup,
grid come to about 10V+, and after this point suddenly drop to proper negative voltage.
I am not worried about excessive plate current, because in this period tube isn’t full conductive,
and plate current is small.
I am worried that in this short period grid can be damaged.
Maybe this is a silly question, they should not to be positive voltage on grid at all,
but which grid current amount (mA, uA ?) can be harmful for grid?
grid come to about 10V+, and after this point suddenly drop to proper negative voltage.
I am not worried about excessive plate current, because in this period tube isn’t full conductive,
and plate current is small.
I am worried that in this short period grid can be damaged.
Maybe this is a silly question, they should not to be positive voltage on grid at all,
but which grid current amount (mA, uA ?) can be harmful for grid?
12ax7
We are JSC "VOSKHOD" Russia Kaluga city is manufacturer of tubes 12AX7( ÎÀÎ «Âîñõîä-ÊÐËÇ» — Êàëóæñêèé ðàäèîëàìïîâûé çàâîä - Ãëàâíàÿ)
We are JSC "VOSKHOD" Russia Kaluga city is manufacturer of tubes 12AX7( ÎÀÎ «Âîñõîä-ÊÐËÇ» — Êàëóæñêèé ðàäèîëàìïîâûé çàâîä - Ãëàâíàÿ)
Hello All,
Very few seems to know the METRIX 310CTR, from the METRIX Company, Annecy, France :
It has the particularity to comply with the tube datasheets to make his tests, unlike the Hickoks and many others that uses proprietary data charts.
The 310CTR measures the plate current under voltages ranging from 50 to 300V, plate current from 3 to 100mA, bias ranges are 0-10V agd 0-50V. If you have the datasheet, then you can test any tube until 300V - most of the tube testers can't do that...
It can also test shorts, and can measure Gm by static grid shift method, but it doesn't measure interelectrode leaks, nor have a gas or life test. The 310CTR is very simple and fast to use, and a reliable, dependable instrument.
A+!
Very few seems to know the METRIX 310CTR, from the METRIX Company, Annecy, France :
An externally hosted image should be here but it was not working when we last tested it.
It has the particularity to comply with the tube datasheets to make his tests, unlike the Hickoks and many others that uses proprietary data charts.
The 310CTR measures the plate current under voltages ranging from 50 to 300V, plate current from 3 to 100mA, bias ranges are 0-10V agd 0-50V. If you have the datasheet, then you can test any tube until 300V - most of the tube testers can't do that...
It can also test shorts, and can measure Gm by static grid shift method, but it doesn't measure interelectrode leaks, nor have a gas or life test. The 310CTR is very simple and fast to use, and a reliable, dependable instrument.
A+!
Good information, Zibi !
I knew the existence of this fine EPO P-508 Polish Tube Tester, but do you know if these are still available ? And where ?
Thanks !
Roger Kennedy, who repairs and calibrates just about every popular tester known, has some recommendations on what testers to buy at his website www.alltubetesters.com--check it out.
Its a shame that all he talks about is the American type testers. mutual conductance is Not suited to match tubes.
best piece of kit for the job is a Metrix 61 hands down the Neuberger and Funke W20 all use a big rheostat for the plate voltage witch means testing tubes can be a real balancing act...
Really nowadays someone can cook up an impressive tester that beats any of the old iron hands down.
best piece of kit for the job is a Metrix 61 hands down the Neuberger and Funke W20 all use a big rheostat for the plate voltage witch means testing tubes can be a real balancing act...
Really nowadays someone can cook up an impressive tester that beats any of the old iron hands down.
What is a crying shame is that you don't need to spend your money on that crap. Build a Fender Princeton chassis minus the preamp (unless you plan to test those tubes too) and add the meters where they belong and you have a tube tester for octals. That is what I did and have added a tester for rectifiers just for fun. It was way cheaper than a Hickok or any overpriced Euro crap! Once you build the circuit for the Princeton you will notice where you can branch off of that circuit to do add-ons for other tubes you may want to test. Just get a datasheet for the tube you are set. Good luck!
Same specs as the uTracer from Ronald Dekker (Ronald's electronic project site) which can be built for much less money and much more fun!
It really is a tube fan´s dream come true.
It really is a tube fan´s dream come true.
Totally disagree. I have successfully built the uTracer and it works flawlessly. Its engineering is simply fascinating, and the attention to detail outstanding. Maybe you are not familiarized with what the uTracer is and what it can do. A quick check of his weblog and construction manual will reveal how powerful this kit is.
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