anyone know if this tube tester will do a good job testing tubes?

Kyle B

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5,290
With due respect, and acknowledging that I have no idea who you are or what level your abilities... suffice to say if you don't have some fairly decent understanding of electrical circuit function, this is probably not going to be particularly usable by you in its current state. You've got to understand what it is you're testing and what results you should be getting, and why, to obtain meaningful results. You might notice there's a couple jacks labeled "6000V". Yeah, you really need to know your stuff before poking around inside or you might get seriously zapped.

If the machine IS tested and verified (and probably subsequently restored) by somebody with some expertise who's willing to teach you it's operation, then sure it'll work for you. It's not rocket-science to set it up. Note it's an "emissions" tester, meaning it will show only the most basic of results... Whether a tube is 'good', 'ok' or 'bad' basically (even then with quite alot of tolerance). I.e. if the needle falls into the 'green' zone it's good, yellow is marginal, red is bad. http://www.retrotechnology.com/restore/precision954.html A better indicator of tube condition is transconductance, which this machine will seemingly not test for.

This guy (whom I do not know nor do I specifically endorse) will calibrate it for $80 https://www.ebay.com/itm/Precision-...062048&hash=item1ed0b619f2:g:KJAAAOSwB-1Ytfrx If true, that's stupid cheap. Or maybe it's just a way to get you to send it to him so he can give an estimate for 'repair'. He's probably an older hobbist or retired pro... dudes with tube expertise are getting more rare these days.
 

Johnny Cache

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570
Nice vintage Tube Tester! Do you have the manual? I grew up using tube testers in my Dad's shop, everything was tubes in those days. I use to have 3 of them but now down to just one, my favorite. There a good tool to have and learn how to use, it will tell you things about your tubes you can't know without testing them. Some people poohoo them, okay, maybe they know something I don't. But I'd rather know more about the tubes I use than less or guess before putting tubes in one of my amps (I test every tube I use before using it) I've found bad tubes I thought were good, especially Russian tubes! with common brand names, you know. And, I've solved some problems quickly finding a bad tube by testing it. Another benefit is, I've come across allot of bulk tubes and old gear and pulled the tubes and tested them and found some nice OS tubes for my use even sold a few. So yeah there are a few good reasons to have a tube tester. If you don't want it I bet you can sell it.

Off hand I can't tell you much about the one you have, but like all tube testers they measure strength of the tube (emission), and test for shorts, some do gas checks (life of the tube), and grid leakage and some can do mutual conductance or transconductance which is hard on tubes usually not necessary. But the main thing is it helps you find a bad tube. As far as the hype with calibrating them. Most the time it's easy enough to do with a known tube in good condition. I keep a few tubes handy for calibration with known values, only used for that purpose. Some testers are Solid State shouldn't need calibration, others like mine have a internal tube, mine has a 6C4 and I keep an extra one as a back up I know the value of (tested), incase it ever needs replacement. BTW I almost forgot mine is self calibrating all you need is a screw driver to set the meter.
 
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HotBluePlates

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14,057
... it will tell you things about your tubes you can't know without testing them. Some people poohoo them ...

The tester in the OP is an emission-type tester. It tests every tube as though it were a diode.

It does have a shorts test, and hopefully has a gas test. Those are important things to check before you get to any other test; however, every other type of tube tester also includes these functions (and will tell you more about the actual performance of the tube).

All an emissions-type tester can tell you (apart from gas/shorts) is the filament is working and the cathode has sufficient emission. I don't know about you, but I want to know more than that...

Check out Tomer's Getting the Most Out of Vacuum Tubes (1961) starting at page 111 for more info.

... some can do mutual conductance or transconductance which is hard on tubes usually not necessary. ...

You have it backwards: a transconductance (Gm) test at least has a bias voltage, and operates the tube with an applied signal somewhat as it would be used in a typical circuit. This is not "hard on the tube".

An emissions test connects every tube element except the heater & cathode to the plate, does not apply bias, and tests the tube as though it has only a cathode & plate. With no bias, there is nothing to limit plate/cathode current except the low value of applied plate voltage. This is hard on the tube, and a long-duration emissions test could injure the cathode.

For amplifiers, you'd like to be able to test the gain or a.c. amplification, and power output for output tube types. Usually, you never see either of those two in old testers, outside of purpose-built test jigs. Instead, transconductance is usually used as a stand-in figure-of-merit which closely correlates to gain/amplification for preamp pentodes, and gives an indication of gain for preamp triodes and power output for power tubes.


____________________________________
(EDIT: There are 2 typos on the upper half of page 115 in Tomer's book. The text says "triodes" but should say "diodes", and refers to the emission-type testers. Tomer states that the heavy current drawn excessively heats grid wires in high-Gm tubes, causing their spacing/alignment to change, and reduces their Gm in follow-on tests.)
 
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Johnny Cache

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570
The tester in the OP is an emission-type tester. It tests every tube as though it were a diode.

It does have a shorts test, and hopefully has a gas test. Those are important things to check before you get to any other test; however, every other type of tube tester also includes these functions (and will tell you more about the actual performance of the tube.

All an emissions-type tester can tell you (apart from gas/shorts) is the filament is working and the cathode has sufficient emission. I don't know about you, but I want to know more than that...

Check out Tomer's Getting the Most Out of Vacuum Tubes (1961) starting at page 111 for more info.



You have it backwards: a transconductance (Gm) test at least has a bias voltage, and operates the tube with an applied signal somewhat as it would be used in a typical circuit. This is not "hard on the tube".

An emissions test connects every tube element except the heater & cathode to the plate, does not apply bias, and tests the tube as though it has only a cathode & plate. With no bias, there is nothing to limit plate/cathode current except the low value of applied plate voltage. This is hard on the tube, and a long-duration emissions test could injure the cathode.

For amplifiers, you'd like to be able to test the gain or a.c. amplification, and power output for output tube types. Usually, you never see either of those two in old testers, outside of purpose-built test jigs. Instead, transconductance is usually used as a stand-in figure-of-merit which closely correlates to gain/amplification for preamp pentodes, and gives an indication of gain for preamp triodes and power output for power tubes.


____________________________________
(EDIT: There are 2 typos on the upper half of page 115 in Tomer's book. The text says "triodes" but should say "diodes", and refers to the emission-type testers. Tomer states that the heavy current drawn excessively heats grid wires in high-Gm tubes, causing their spacing/alignment to change, and reduces their Gm in follow-on tests.)

I knew someone would fly off the hook about my post. And I'll do you the favor of one reply.

I don't want to argue with you the differences in tube testers, okay. I've been doing this along time, and almost everything I've ever tested had an amplifier in it, TV and radios for example. Emission testers do a good job of basic tube value and don't stress the tube at the voltages used, measures resistance of the plates. The other test like shorts are also important and can prevent equipment failure. Transconductance is supposed to replicate performance, same as in application and is probably good for matching tubes.

So what hear you saying is the his tester is worthless, I disagree. It's a good place to start learning about tubes and electronics. From there if he wants he can move into more advanced electrical and tube theory. End of story.
 

HotBluePlates

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14,057
I knew someone would fly off the hook about my post. ...

Just giving the rest of the story.

... So what hear you saying is the his tester is worthless, I disagree. ...

I didn't say "worthless" anywhere in my post. I said what an emission tester can do, and how it does it. I also indirectly said an emission tester doesn't meet my needs.

Flip to the back flap of the book I linked: the author was the manager of field engineering for CBS Electronics, a tube manufacturer. I think there's worthwhile insight there.

Regardless, use what you like & I'll use what I like. Everyone is happy...
 
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Johnny Cache

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570
Just giving the rest of the story.



I didn't say "worthless" anywhere in my post. I said what an emission tester can do, and how it does it. I also indirectly said an emission tester doesn't meet my needs.

Flip to the back flap of the book I linked: the author was the manager of field engineering for CBS Electronics, a tube manufacturer. I think there's worthwhile insight there...

No I said worthless, because that's what I got out of you message, I apologize if I offend you. I understand the tester in question wouldn't meet your needs, probably not mine either. But for someone just getting into it or wanting to mess with tubes it's a good place to start. Emission testers may be limited but they are a pretty cheap to get and good learning tool. A good Transconductance tester could put you back 100's of dollars, probably not worth it for most guitar players.
Anyway have a nice day....
 

JJman

Member
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994
Very similar to my 920 model. I see an issue. I don't see a 9pin socket (e.g. for 12ax7 type tubes or el84 or many others.) My 9pin socket was changed when I got it and I changed it again myself due to poor contacts. Mine is from 1947 IIRC. It did not have EL84 or 6V6 on its roller but I found a supplement and some data from a guy to fill in those gaps. There's a battery in mine that still has juice.
 

HotBluePlates

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14,057
... There's a battery in mine that still has juice.

That's almost certainly for the resistance measurement feature. Having volts on the battery is not the thing to worry about, but rather having an old battery that corroded and is leaking. A visual check will let you know whether that's the case.
 

Kyle B

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5,290
That's almost certainly for the resistance measurement feature. Having volts on the battery is not the thing to worry about, but rather having an old battery that corroded and is leaking. A visual check will let you know whether that's the case.
I second that. A battery from the 1940's that's still putting out charge? Ehhhm.....
 

zenas

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8,871
My tube tester is a little one a TV repair man would take on house calls, probably dates from around 1970.
Really only good for telling if a tube is completely dead or probably safe to stick in an amp. After that I just listen to the tube compared to a good one.
Originally I wanted a better tester but at ham fests all I found was old testers that nobody would plug in and show me they worked. Manuals were missing and some had the cords cut or rotted off. I like projects but rebuilding a vintage tube tester doesn't sound like a lot of fun.
So I over payed at $100 for the little tester. But that price included a couple hours talking to a really nice old electronics guy, him showing me the tester doing it's thing, coffee and his wife's cookies.
It really paid for itself when my dad brought over an old Zenith radio/record player that didn't work. With an amp I've got spare tubes, this thing was full of glass I don't keep handy so I grabbed the tester and found a bad oddball rectifier tube. Luckily when I started digging through my boxes of tubes I should throw away I found the right tube and the thing works.
Then I spent an hour explaining to my dad that, just because it works doesn't mean it won't burst into flames. He sells antiques and this thing is worth maybe 50 bucks on a good day and going through it replacing dried out capacitors won't change that.
 
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I believe that emissions testers have their place, and I am glad that HotBLuePlates shared the information on their shortcomings with me in another thread a couple of months ago. I did a bit of research and found out that there are problems with the emissions testers regarding how the cathode is treated. I have come to the conclusion that perhaps an emissions tester is a good piece of handy equipment in some situations as long as the emissions test is made as short as possible. The tube should not be subjected to being in that emissions test mode for any length of time. I know that HBP is of the opinion..based on firm tube electronics....that one should not use an emissions tester at all, but I think that used with care for the cathode they are of value to some.
 

59Vampire

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I am a tube collector and hoarder. I have both an emissions tester and mutual transconductance tester. I only use the transconductance. For my needs,the expense was worth it. I have thousands of tubes. The average non-geeked out guitar player does not need to spend money on a tester and is better off spreading out that money spending it on quality tubes from a respected dealer who does the testing for them.

In my opinion, if you feel you need to test a few tubes you picked up on the bay or at a garage sale, dont waste your dough on an emissions tester, or heavens to mergatroyd (LOL) an Orange tube tester, get yourself an inexpensive single ended tube amp and use that before you pop them into your vintage Fender/Marshall/Insert boutique brand here amp. Not only do you get a legitimate way of hearing the functionality, but you get another amp! :)
 
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I agree that when it comes down to it, the circuit is the only tester that tells you what the tube is doing.
59Vampire, I know nothing about the Orange tester. What concerns do you have with that unit?
 

Johnny Cache

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570
I'm glad you mentioned the Orange Tube Tester, what a joke. It's a wall-wart powered gizmo with a limited range of tubes. Maybe it's okay for basic stuff, but for the money it's not worth it. I don't know anyone with one but I assume it's an emission tester.
 

Kyle B

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5,290
I'm glad you mentioned the Orange Tube Tester, what a joke. It's a wall-wart powered gizmo with a limited range of tubes. Maybe it's okay for basic stuff, but for the money it's not worth it. I don't know anyone with one but I assume it's an emission tester.
You inspired me to look. According to the manual it's a little more complete than that
https://orangeamps.com/wp-content/uploads/2014/01/Orange-Valve-Tester-Manual1.pdf
Orange Tube Tester Manual said:
Testing sequences include:  Heater filament test: Short circuit  Heater filament test: Open circuit  Heater filament test: Tolerance check  Heater cathode insulation: Leakage  Heater cathode insulation: Short Circuit  Tests for heater current abnormalities  Amplification factor  Voltage gain  Power gain  Screen grid test  Mutual conductance test  Dual test for double triodes  Emission  Inter electrode leakage  Inter electrode short circuit  Flash-over (arc detection, high voltage breakdown)  Gas ionisation test
Supposedly this will match tubes

I've always been a bit puzzled by the very high price of it. If you limit yourself to the main few Guitar tubes (like this tester does), then it shouldn't be a very expensive or complex piece of equipment to build.

Anybody wanna help me design a tube tester kit?? :)
 
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6,608
I read one review which experienced a 'match' that was off by 30%. I read that it actually tests at 'specified anode voltage'. Another review ran a known-to-be-bad KT88 through 10 tests before the unit finally found the tube to be bad. I am not interested in one but am interested as to what they actually do. I know a fellow who has one but have not seen or tried it out. I have a couple of big Hickok's that I trust. And...I will use an emissions tester in certain situations.....while being sure not to have the tube in the emissions test mode for long.
 




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