This is my attempt at an introductory video on tube testers. I hope this video will become a place where we can all share information regarding tube testers, where we can ask and answer questions that are so often hard to find online.
Last year I completed my project of assembling a uTracer kit. Highly recommendable. New version uTracer 6 has B+ up to 1000 V and plate currents up to 1 A. Note though, that kit has only the electronics PCB without case or tube sockets. You can directly compare your tube to the data in tube manuals. Indispensable if you want to accurately match tubes.
This is fascinating to me! Thank you for making clear your grasp of the subject matter. It is amazing that anyone still even remembers tubes! I was born just after the heyday of basic circuit design for tubes, but WOW, did they guild the lily afterward! PS: I still live in a world with Mhos!
Exceptionally informative and interesting. I remember the tube testers in the drug stores. They were crude, but good enough to identify the bad tube to get the tv working again. Used them many times. In the 60's. Now I feel old. Have a couple testers I have used on occasion, other projects getting in the way. Maybe a follow-up video repairing that TT-1 meter.
Newest tube tester to my knowledge is the Roe Test by Helmut Weigl from Germany.He developed it but you build it yourself as I understand it,and its computerized.Thanks for video.
Thank you so much for this Tony! Just wish you'd had a B&K, amplitrex, or maximatcher in your arsenal to share! I stumbled across several EMC 213 and 215 emission testers and haven't found the need to upgrade. These goofy little things are STELLAR at sniffing out shorts, but finding gassy tubes is a bit more tricky. I've found leaving the tube cook for a while under test will diagnose a gassy tube as with some time the emission will drop off either a little or a lot depending how bad it is. Yeah these emc's aren't a MC hickok but they have worked wonders for me........
It’s a Eurotubes “Pro One” which, yes, tests plate voltage and current to bias the power tubes. Not really a tube tester at all. You could make one if you don’t mind 380v going through your hand if you didn’t insulate it properly. ;)
Excellent video very informative and helpful I have a hickok 752 tube tester works very well and accurate tests dual tubes very fast cause don't have to adjust switches just press plate 2 button :) looking forward to future videos
I find it ironic that 50 years later in my electronics journey that I finally know what micromhos mean. Resistance in OHMS and the reciprocal, conductance in MHOS, never really gave it much thought. My channel picture is from my Mercury 1200 dynamic mutual conductance tester. I also have a Hickok cardmatic tester which needs repair. Love these learning videos.
I remember they had tube testers at the local hardware store I actally used it a few times to test tubes on my parents old TVs. That was the start and end of my tube days.
I've got a Heathkit TT-1... after seeing this, I'll have to go through the calibration procedure and see if the meter is working correctly, hadn't known before about that potential problem.
Good intro video for tube testers. Makes me want to fix the Sencore solid state one I overpaid for. One of the wafer switches has a bad spot on it from a previous owner /hacker! At least my Heathkit TC-2 works great!
The TT-1 is a copy of the Weston 981 type 3 . The Weston is much easy to work on it is a 5k test signal the 3c4 is the oscillator tube . Given the choose take the Weston and use the TT-1 charts covers a lot of tubes . For big money the Etracer and Utracer generate very detailed info on the tube curves.
YES!!! That terminology as an engineer is driving me CRAZY!!!! LOL, if you send me your address I can send you my Medical Bill from my doctor who said to me, Just dont watch his videos!!!!!!! 🙂 Also, I always wondered what NS stood for on my Fluke 187 meter was used for?? Funny how you can be involved in electronics for 50 years and learn something new after all this time. This video definitely gets 5 Stars for teaching and learning!!! BTW, I own 5 tube checkers, my AVO MK IV,, is So Complicated but it can do everything for sure... I use it to get matched tubes for high end Guitar Amplifiers. It helps to sell high end Fender guitar amplifiers.. Robert
Stark is a Canadian brand that used the Hickok wiring. So a Stark 8-77 is basically a Hickok 6000 and a Stark 9-66 is basically a Hickok 533 (or the Hickok 750 can't remember). There were some very slight differences with dials and resistor placement but can calibrate very similarly to the Hickok's. I have both of these stark versions. So if you see a stark don't hesitate to buy it.
It's very important to ALWAYS do the SHORTS test before checking Gm. If there is a short in the tube and you press P4 you most likely will trash the bias circuit and/or meter. There is no overcurrent protection for the bias circuit and probably the most important mod is to add that.
I agree. For the cost of a #49 bulb and a bayonet socket, the bias fuse upgrade is a must. The older Hickok testers had this feature and for some reason they omitted it in the 539 series testers.
Yah not sure why they didn't have it in the 539 series they where better then the other hickok testers cause of the dual transformers and can readjust voltages with tube still under test.
I am an expert on Vacuum Valves and the testing thereof. There are many testers out there. The-best one to use is the one you can afford. Ove. Worked in the electronics field for 60 years and most of those years I never had a tester. However I had a very good stock of valves. These days I no longer have the advantage of a good tube supply. I live on a-fixed income. So I choose a tester that checks for shorts, gas and emission. I just really want to know is my tube in question good or bad, nothing more. I chose a Triplett 3413 emission tester. Its like the EICO basic model and a few others. It has never failed me. Correct I cannot measure Transconductance. Most of the vendors have the Hickok model that measures Gm. Im very pleased with my Triplet and understand its limitations. O
I have a Hickok 532 mutual conductance tester that works well and it calibrated but the octal socket is about shot as I have to tug on the base of the tube inserted into it for it to make contact. The rest of the sockets are fine. I also have a Philco 7050 tester that I bought a couple years ago and have yet to open up and go through. It looks like the neon shorts bulb in it is broken, but I could be mistaken. Some day I'd like to get a small emissions tester as 99 times out of 100 I'm sure that'd be good enough for my needs. Something like one of those little Knight or Heathkit testers. I use the old terminology as well. When I say Kilocycles or Megacycles I get the same reaction, lol.
Conductance usually is used for non-solid materials with very high / extremely high resistance, like liquids, gasses, plasma. It is easier to use the reciprocal unit: mS, µS, etc instead of resistance. Since tubes work in (nearly) perfect vacuum conditions, it is more convenient to talk about conductivity than resistance.
Hey Tony, have you ever thought about doing a video on the dangers of X-ray radiation exposure around old CRT TV's and other high voltage devices? How would one check to make sure the shielding is providing proper safety from exposure? What would you use to check for X-ray leakage? I could not think of anyone more qualified on this subject than you. Thanks, let's keep each other safe.
Some comments and information that others will hopefully find useful: first of all, Tony didn't really delve into the shorts, leakage, or gas tests, which are the most important tests of all because of the very real possibility of damage to an amplifier or radio if you try to operate the device with a shorted, gassy or leaky tube. In a properly functioning, well designed tube tester, the neon-bulb "shorts" light should light up brightly if it encounters a shorted tube, but it might not light up for a tube with inter-element leakage, essentially an unintended and unwanted resistive shunt between any two or more tube elements. The "shorts" bulb on a Hickok might light up (dimly) for leakage of up to about 200k to 250k at most; but testers such as the 539 and 752 series read inter-element leakage right on the meter itself, up into the *meg-ohm* range; a much more sensitive and revealing test, and important because leakage can cause noise, hum, erratic bias and red-plating, loss of frequency response ( especially for RF circuits) and intermittent gain. Ideally you want to see NO inter-element leakage. BTW, I have encountered tubes, especially mini 7 and 9 pin tubes, that showed leakage on the meter of my 752A until I cleaned the tube bases and pins with alcohol and a toothbrush; dust and grease, or contact cleaner residues, can cause leakage current between tube pins, and tube socket contacts as well, which is why I don't clean tube sockets with anything other than pure alcohol. This goes DOUBLE for tube tester sockets and switches ---- use a pure evaporative solvent for cleaning, don't spray the switches, controls or sockets with Deoxit or anything else that leaves a residue. I'm sure at least one person here will try to tell me otherwise, but I've seen testers that were irreparably damaged by use of ordinary contact cleaners, so be forewarned. Tony didn't show the inside of any if his testers, but believe me, you don't want to replace tube sockets unless you absolutely have to. You have to get past layers of wiring in order to access the underside of the sockets. Its not quite so bad in a physicalky large 533, 539 or 752, but changing a socket in a Hickok 600 or a TV7 or any of the other small chassis models is a nightmare. Testing tubes for grid emission, or "gas", usually requires letting the tube get good and warm for ten or 15 minutes. On most Hickok testers, the shunt pot has just two functions --- it is used for the gas test on triodes, tetrodes and pentodes, and for setting the meter sensitivity when testing diodes and rectifiers (which don't have mutual conductance). Going through some of my junk the other day, I found an interesting piece of test gear I'd forgotten about: a SECO Grid Circuit Tester, model GCT-5, that uses a "magic eye" tube ( a 6AL5, IIRC) to test tubes for interelement leakage, grid emissions, and gas, presumably in somewhat similar fashion to how an old Sprague capacitor-bridge tester works. I've never tried it, but if it's anything like the circuit for the upgraded GCT-8 model that I found a schematic for online, there's not much to it ---- a handful of resistors, a capacitor or two, a filament transformer and a couple of switches. I'll have to check it out further. The GCT-5 has miniature 7 and 9 pin sockets only, some of them being marked for 6AU6, 12AX7, and the like, and I don't know if it can be used or adapted for EL84'S and other output pentodes. The GCT-8 has octal sockets and apparently tests more tube types.....
I'm glad you said this about cleaning the pots and sockets with Deoxit, I just got a Sylvania 220 to mess around with and was going to do exactly that today. The tester seems to work great, although I didn't calibrate it yet. Thanks! (I didn't get as far as figuring out if I can test EL84's yet, which I have dozens of)
@@2tallB , I'm glad to hopefully be of help to you. I am a firm believer that he who who cleans with the least amount of contact cleaner cleans best! At the audio repair shop I work for, a lot of switches, relays and controls get cleaned with nothing more than a pencil eraser and alcohol, or perhaps a fiberglass- bristle "scratch brush" if the tarnish is really heavy. Contact cleaner is applied to potentiometers in minute amounts with a syringe, rather than flooding it with a blast from a spray can. Some things such as slide faders and rotary encoders really can't be cleaned properly unless you take them apart and polish them with the pencil eraser. By the way, the best method to clean dirt and tarnish from the miniature 7 pin and 9 pin tube tester sockets is with a wound guitar string of approximately .033 to .039 (housandths) diameter, that you work back-and-forth inside the contacts like a miniature round rasp or file. If you can find a way to spin it with a small Dremel tool or something similar it becomes very fast and easy (Harbor Freight sells a small battery powered engraver for about 8 bucks that can be adapted to fit the guitar string). Flush the tube socket contacts with pure alcohol afterwards, and retension them with a small jeweler's screwdriver or dental pick.
If your tube variety not great, build one! Info is on the back of RCA tube manual, easy to make One that test dual triode or matching two tubes w/o switching like mad and at operating condition .
The line adjust rheostat when set to the red mark, assures the correct primary voltage is applied to the two transformers (filament and bias/plate supplies). The correct supply voltages are assured by this setting. The calibration tests and adjusts these circuits. The end result is the correct voltages of the associated supplies. If the line meter is inaccurate it throughs off everything that follows. On the 539C, the bias meter is a milliamp meter with two switched series multiplier resistors, giving two ranges:0-10, and 0-50V. The accuracy of this meter is determined by these two multiplier resistors.Because these two resistors are switched it’s impossible to monitor this voltage by bridging the meter movement. Because of the unique circuit design I find all adjustments seem to effect the next one. All adjusts seem critical to. The next. I have yet to find a clear description how the Hickok transconductance bridge circuit works. I believe, When the tube is being tested, a pulsating (half-wave) ac signal is added to this unfiltered dc bias. This is the “dc bias plus “ac” (pulsating dc) applied to the grid of the D.U.T. I believe The transconductance is measured by monitoring the effect of the input signal on the plate current by use of a bridge circuit, giving conductance in micro-umhos. I wish I could find a more better/detailed description. A common modification is adding the additional #49 bulb in the dc bias supply. The bulb limits the current, like a dim bulb tester, such that if the supply gets shorted the bulb resistance increases limiting thus protecting the bias supply. Under normal circuit operation there is little current flow and the bulb’s resistance does not affect circuit operation. This enhancement. ( #49 bulb ) is in the Hickok 6000A tester circuit. Please accept these comments as my opinion based on my own study and operational experimenting with my own tube testers. I may be be in error, but I offer my observation for discussion. I do not claim to be an expert in anyway.
Thanks Tony, I have a Heathkit TC-3 that I purchased to check my 300b and 2a3 tubes, before using in my Amplifier. It has been interesting to watch the tube degrade over time. Should I stop using a tube when it gets close to the yellow zone or questionable status? Can it damage my amp if it fails while in use? Your input would be greatly appreciated.
Make a ss83 to replace your 83 tube in your tester. I built one for my hickok 752 works good all tubes test with simular results. Don't have to wait for it to warm up either :)
I have the Heathkit TT-1 with the late Meter ( or should say the Reliable meter ) and Works and Calibrates perfect and works Excellent and Have the Triplett 3444 but just don't like it, but the TT-1 and Hickok 539B that I have give Very close Results, I have more Tube testers than Tube projects :)
The Triplett 3444 & 3444A show plate current and the 3444A's meter will handle 1.5 amps on the plate. They also run at common USA EIA test voltages of 250 volts plate. The Triplett also has a small 5000Hz signal generator so the tube is amplifying a 5KHz signal. I own the Hickock KS15750 which is a 539B without the plate current terminals but the Western Electric KS15750 testers generally came with an optional decade box made by Davies that was used to bias the cathodes on some tubes. To find the BOGEY or factory specified GMHOs divide the minimum by 0.55, 0.6 or 0.55. Tolerances were +/-20% anyway. I need a lift ring for my KS15750A. It dates to 1943? And it has the very last chart from Fall 1974 in it. It was heavily used and abused.
I bought a Heathkit TT1 kit NOS still in the original Heathkit box, still 100% "UNASSEMBLED" at a garage sale. What a mess of crap! Holy smokes! What a bunch of bits & pieces!
Yes, the AVO VCM163 also uses the valve under test as an *oscillator*, so it is by far the most accurate method. I cover this in: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-ITJE4f-oVfc.html
I have replaced my RCA card reading tester with a Hickok, 533A. It is very similar to your 539 but with only 1 meter and additional scale on the meter to get the same live voltage function that you have a meter for and the bias is set with a scale on the adjustment knob (like your shunt knob) rather than a stand alone meter. I have no idea how many revisions my roll chart is behind but I just downloaded the PDF of the latest edition and keep it on a tablet on my bench. There are some known mistakes on it but it is very easy to scroll to the tube you want, you might think of doing the same. Once you have it on a PC or tablet, the roll chart is very slow to use. Just saying!
The 533a is like all other hickok testers. 600a, 800a, 750, 752 which uses a bias control which is tapered with very fine wire and has a bias fuse to protect it. The 539 series is the better tester it has 2 transformers instead of 1 and the bias control is an actual potentiometer so more durable hense why it doesn't have a bias fuse. The first transformer is for the heaters of the tubes and the second transformer is for mutual conductance tests so it increases accuracy then a tester with a single transformer.
I’ve recently inherited a NRI 70 and a precision 920 as well as a larger amount of various tubes… I wanted to get them to a good home but not wanting to give them away… I know I’m over my head with how to test the tubes with the units to insure that the tubes are good and matched… need help Thanks in advance
Tanks for the video. How would one buy a good and not too expensive one and ship it to EU? Because there is no way of knowing how good it works, when looking on let's say Ebay.
I'll be building the uTracer 6 that uses pulsed voltage to develop tube traces. High voltage too - 1000v. I need to be able to test and match power tubes eg 811, 6146, and 572's. Ought to be an interesting project. The problem with the older ways is the need for especially high voltage power supplies > 400v for plate voltage. The uTracer just uses an old laptop supply. I can still use a 400v unit to calculate Gm as it is the CHANGE of plate current over grid voltage, it just doesn't fully load the power tube. 73 de WB4YDL
More likely you should have a good transistor tester, but you can check bipolar transistor any using the ohms range of any VOM, there are $10 LCR testers that will also test a transistor and identify leads. If you know what you are doing, you really don’t need an expensive tube tester. If you have a short in your tube, the radio will tell you with symptoms or burned components. Good / Bad is all you need to know, except….except if you are selling tubes you need to provide Gm values to your customers, who really don’t know much either. Good day chums!
You don’t even need a tube chart. A good tube manual will identify the pins where you can see what pins you are grouping. You can select test mode by identifying the power range setting and filament is an obvious setting.
Hello, I have 2 Heathkit tt1, one works perfectly, the other does not allow calibration, I think it has the same problem as yours, could you tell me what values are the resistors that I should replace in the meter, thanks in advance
The problem, acording to the PeaVey repair tech I talked to is, the particular class or model, mine being the early 80s PeaVey VTX series classic 212 hybrid guitar amp. The power section runs off of 2~ 6L6GC tubes and the pre amp section is solid state. Anyway he told me the vtx and the vt series when the tube goes bad it instantly destroys its solid state driver. And when the driver goes bad, and you put a new tube in without replacing the driver you ruin the tube? Anyway, you get an expensive ping pong effect acording to PeaVey. That’s why I’m purchasing a used tube tester when I find one, so I don’t have to buy a dozen tubes to get my amp going.
Hey, Tony, I noticed your bottle of Vinegar on the bench. Do you use that to clean up after solder jobs in lieu of iso-propyl alcohol? If not what do you use it for?
I use it to clean corrosion from battery terminals and metal parts that get that white fuzzy corrosion on them. I take a small artist's paint brush and cut the bristles short (to make the brush stiffer) and then apply the vinegar directly to the terminal. Often, it will clean the corrosion right off. Thanks for the question!
@@xraytonyb Cool, I thought it might also work for cleaning component leads before soldering them in. Obviously probably would be to good to get on the board to clean up flux, post-solder. Thanks!!!
About a year ago, there was a triplet 3444 tester for sale on the local Craigslist for about three hundred and fifty bucks. I deeply regret having not jumped on that deal. I think that is one of the best testers that exists. And you're not going to find one for 350 bucks.
Theres also a re-branded Triplet 3444 , badged as a "Westmore 501". *Same exact machine as the Triplett*. I corresponded with test-equipment guru Alan Douglas (author of "Tube Testers and Classic Test Equipment) about it some years ago ---- he confirmed that it is indeed a 3444 in sheep's clothing, but we couldn't find any info on "Westmore".
You dont happen to have a Sencore TC 131 around, do you? I bought one without the setup chart, and it is the only sencore product that you can not find the setup charts online... It is totally different than any other sencore product 😢
Mutual Conductance. I believe that there were more than one company that built them, but I think the main manufacturer of them was Hickok. (Somebody correct me if I'm wrong). They are very good testers and really well-built.
Concerning emissions testers, your video suggests a tester that measures only cathode to plate emission is least desirable of all testers. How is the tester you demonstrated that connects the plate and grids together any better? Both emission measurements are only a relative indication. One cannot be better than the other. What relevance is connection to screen or suppressor grids, and their corresponding emission, other than some effect just proving they are active somewhat.
A forum would be wonderful I have five testers and don't now if they work .I tried my superior and the tube lit up and blew out and my two hickoksa 3000 and a 600 I believe thats what thay are. i have not tried one don't have the chart roll. The other two are small ones .I wish someone lived next to me because I would give up a few for free if someone could get me going on the best on . I got exited when I saw this vidio..I build tube amps as a hobby and I just buy new matched tubes instead of testing the hundreds I have in stock and that is stupid on my part. I opened one tester up and saw all the wires tony speaks about that was enough it went back together and forgot about. Maybe this winter I will get into it if I can find the info or a person to help
Very good question! I'll try to explain it, but I know some of my friends could do a much better job of it. Here it goes: Just as we use the letter I as the symbol for current, V for voltage and R for resistance, the letter G is the symbol for conductance. Resistance (R) is the measurement of the opposition of current flow through a circuit and conductance (G) is the measurement of the ease with which current passes through a circuit. They are reciprocals of one another. In other words, a 10 mega-ohm resistor (10 million ohms) will read 100 nano-Siemens (or 100 nano-mhos) of conductance. 10000000/1=.000001 siemens (or mhos) (I hope I have the correct number of zeros :). The letter m (lower case) stands for mutual. Put it all together and you have Gm= mutual conductance. Mutual means that it is relative, or tied to something else. In this case, it would mean the relative change in value between the grid-cathode and anode-cathode. So Gm = mutual conductance = transconductance = gain. This only applies to DC levels. When we work with AC signals, we use the term admittance. Admittance is the reciprocal of impedance. It's very similar to resistance and conductance, except you have a phase angle component between current and voltage that affect the impedance/admittance (enter ELI the ICE man ;) ) Hope that helps, and forgive my feeble attempt at this!
@@xraytonyb You are too modest, you did an excellent job. I don't know how it could be made any clearer. Thank you for that, I feel a bit more enlightened now.
In my electronics classes we were taught to use E for electromotive force, and not V for volts, hence the E in ELI. VLI the ICV man? We won't mention the non politically correct ways to remember the resistor color code we were taught.......
Unfortunately, the Arthur Treacher's in our area closed down. One of my favorites for fast food. Now the memories (and vinegar) are all that remain.... ;)
