Not new to electronics, but new, and novice, to the valve world. I have followed this series with great enthusiasm and learned a tremendous amount about valve behavior and requirements on here. With your excellent and thorough presentation skills, I found this a joy to follow. Thank you for this upload and the trouble you took. Much appreciated.
As a soon to be retired electronics engineer, I admire your sensible and simple approach. I shall be keeping my hand in by restoring valve radios for my own pleasure and a decent valve tester is an essential tool so thank you for doing the hard work. I plan to use a pair of extra secondaries to work the meters and the heater supply. I shall be adding a higher voltage heater supply with a switched current limiter (LM317) to supply 100,150 and 300mA for Uxx Hxx and Pxx valves which are common here.
The constant current heater option is a great idea, especially for those types of tubes. I very rarely come across them, so did not make provision for that. Have fun.
Hi Manuel. Superb series from start to finish. I have used some old tube testers in the past, but I've never looked inside or fully understand the ins and outs of how they worked. Watching this series and seeing your very detailed demonstration, I feel like I've have learnt a lot. Your projects are always very interesting, but this has to be your best yet. Again thoroughly enjoyed watching this series. Cheers Chris.
EXCELLENT !!! I’ve decided to have a go at building this tester , going to have onboard sockets for the audio amp/ and preamp tubes I generally use and a socket outlet for any oddball valves I encounter , I’ve ordered the pcbs …. And led meters, can’t get the peak meters in the uk for a relatively cheap price as far as i know can’t wait to get started !!!
@@electronicsoldandnew Thanks , i have an update , got the pcbs , (great quality ) ordered a custom toroidal transformer 250v@2A and 8v@5A , even found a pcb on pcbway that gives me octal, Noval7 and Noval 9 on a single pcb with paralleled pins so I don’t have to do the tricky wiring of the sockets !! I have three sets of these pcbs going spare ( psu pcb, opto/relay board , and the tube base board) which I’m willing to pass on for a minimal fee ( to fund the build )plus postage if anyone requires these please drop me a msg ill keep you guys posted on the build
Fantastic. I really admire the neat wiring. So many wires needed, and everything looks clear and comprehensible. Knowing that tube testers are either very expensive or in questionable state due to age, this will help many people. For absolutely sure a project to consider.
Amazing! Truly one of the most impressive projects/builds I've seen in the vintage electronics community here on RU-vid. Also, you really tickled my cable management OCD with your fantastic and clean layout. Many congratulations! You really hit the ball out of the park with this one. 👍
Looks absolutely fantastic and the circuit design is absolutely brilliant. So neat and clean. Lots of functionality without being too complex. Thank you for sharing this project. :)
Excellent presentation of the complete project. I'm just waiting for the pcb to arrive to finish the tester. Will send pics when all is working. Cheers Manuel.
Very nice. I can't say I'd feel comfortable mucking around with high voltage, so I will pass, but do appreciate the heads up on the programmable meters. I too use 1/2 inch or 12mm MDF board for building instrument molds when building stringed instruments. Nice material. A bit soft on the edges and pre-drilling for screws I always utilize. The board does finish nicely. I like using shellac as a primer on the MDF for later top coats of the final finish. As a primer I thin the shellac with denatured alcohol at one to one and rub it on with a cloth. Shellac is self wetting thus it does not need sanded between costs. It also dries for re-coat in as little as an hour. I normally place two coats of thinned shellac down as a primer and then the top coat. Frankly I am a fan of oil paints as a top coat because its binder gives it a richer look, but pretty much anything can be painted over the shellac primer. Another nice feature of shellac is it can cover anything and prevent any stain from telehraphing thru into the top coat's surface. Some times one might even use shellac as the top coat but it is suseptable to alkaline infused water such as sweat thus for top coats on an instrument it is not a particularly good idea. Another nice product to try on woods and likely not MDF would be rub on oil finishes such as Tru Oil or Boiled Linseed Oil or Tung Oil. They give a beautiful finish if your enclosure is made from hardwood veneers or panels.
Brilliant, I've enjoyed the entire set of videos, especially the development process. I can't think of anything more it needs apart from possibly four little rubber feet and a carry handle on top.
Never seen a zenner ladder before; can you mix and match zenner diodes in the chain to arrive at your reference voltage? So instead of using 5 x 51v to get 255, if you wanted 265v can you put 3x51v and then 2x56v all in series?
Yes, that’s it. Just make sure the diodes require about the same current to provide the rated voltage, because the same current flows through all the diodes.
Hi Manuel, a very nice project. Unusual theme of building up a test device for tubes. I want to draw some attention to a project here in germany for a rather complex tube tester. Perhaps you know it. Its the "RoeTest" from Helmut Weigl. You can search for it, not allowed to public links here in YT. Its a professional tube tester, much more expensive, but really awsome. The project is DIY, but not open source, The software is closed source, but you can buy the Schematic, programmed CPU, some special parts and the Docu. I had built it end of last year, very impressive. Advantage is the intgrated database and automatic measurements and check of tubes.
I am only about eight minutes in, but wanted to throw this comment out there before I forget! You were going over the connector you use for choosing the pin connections and such, and it occurred to me that you could set up an interface to your computer where you would choose the tube, it would set the pins, and give you all the info, charts, etc. on the screen. A future enhancement to consider!
The idea being that it is plug-n-play in the existing port, no modification of the tester required. This is an awesome tester, and I’ve really enjoyed the series! I am fairly new to the old radio restoration hobby. I’ve got an old Eico 625 tester that I’ve restored that is more than enough for my needs at this time, but I’ve learned so much watching this series that I can’t stop thinking about tweaks I “could” make! 😂 I’m going to go outside before I bring down our power grid… Well done!
It kind of looks like and LCD TV WOW! Maybe one viewer designs that stuff and can convert this marvelous machine to some kind of flat LCD TV design with flat connectors and modularity like they do with LCD TVs nowadays although I’d bet that would be really expensive for a hobbyist. Anyway I digress, thank you for the great video and keep up the great content Manuel!
Thank you for sharing this tester, I received the parts and am building at the moment. One thing I just realized, the transformer I sourced from an old radio is centre tapped and putting it through a full wave bridge rectifier will double the voltage? Do you think the circuit will handle it, if I up the C1 & C2 voltage? All my old tube era transformers are centre tapped, and using 1 winding would halve the current capability, any ideas?
Thank you, it will be easy to slightly modify your circuit board. I was thinking of a full wave centre tap diode rectifier, just wanted to check I wasn't missing something here.
Thanks for sharing! I am about to build a tester too based on the Valve Heaven design but for more precise bias Im going to be using a LM337. For transconductance I am going to inject a 1v 400Hz sine to the tube under tests grid and measure the result on the plate when I increase the grid voltage by 1v.
@@electronicsoldandnew I'm quite a newbe on valves although I have worked on electronics musical instruments for over 35 years (starting at Roland UK in 1988). It may interest you to know that I bought a Hickok TV-3 CU recently but it was not fully functional as the seller said and I had to return it. These old units are not precise and setting grid bias on these was very hit and miss. BTW I see you have a South African accent (sorry if I'm wrong); I did work on some Just Jinger equipment a long time ago.
Two questions follow. I'm in the middle of building this project and it has been a wonderful learning experience. (1) When testing an EL84 pentode, would you connect the cathode directly to ground (the 0V pin) or to ground through a resistor? (2) I'm using an analog meter and switched shunts to measure anode current over the 3 ranges in your design. What would you recommend as a way of making fine adjustments to the shunts, if necessary, to properly calibrate the meter? Thank you for a fascinating project and a very educational channel.
good day, I have watched with great interest your youtube videos about the DIY tube tester. The most I like is your solution to power the LCD meters via optocouplers. I personally opt for DC/DC converters from Murata, for example. douwe
Wow, so nice a project! Was a treat to see this. I have some old valves in unknown state, so this is surely interesting to me. But I will make it much more "temporary " than you, just the (labeled) wires sticking out of an installation enclosure, without meters ... I don't have power transformers in excess, so I'm planning to go with the module you used at the beginning (have some of them at home alrealdy), in connection with computer PSU, which gives me all the needed voltages (12V to supply the HV module, 5V to supply DC-DC boost converter to feed the heaters, -12V to supply the bias voltage)(earth connection of the PSU removed to isolate it). Question 1:To set bias voltage an ordinary 1K 24mm potentiometer seems adequate, on 12V it limits the current to 12mA, which gives you 0,144W, so well under the rated power of the pot (0,5W)(current to the grid is neglectable I suppose? - if the valve is not "gassed" ...) - otherwise I can use LM337 Question 2: Why use this 5 zener array and not stick the B1 setting pot directly to HV rail? Do you really need this "reference" for it to work? (obviously I will only need the screen part of the mosfet regulation circuit and there it is not present, but still ...) EDIT: I think I got it - transformer "sags"under the load slightly and so the dialed in voltage drops, when connected to the tube, am I right? So I don't need this assembly when using the forementioned module? Question 3: If I use a higher value pot for HV setting (1meg), couldn't it be an ordinary 16mm one? They are rated for 250V if I remember correctly. EDIT: Went to check - they are rated for 200V, so I must go with 24mm pot (they are rated for 500V) (higher resistance of the pot limits the current through the pot to 0,3W which is beyond the rated 0,5W of the pot, wiper current being neglectable) Question 4: The mosfets I have in supply have a built-in 30V protection zener both ways between gate and source - do I still need the 12V zener you used? Yo explicitly said you don't have time to answer in depth, so I would be happy just of short answers, and maybe a link where to learn from. Thank you in advance! Although I'm in guitar amps and not radio (so more after the parts you work on amplification and power supply parts of radios and listening to alignment and simililar stuff with just one ear) I really like this channel, everything is explained clearly and with grace, and there are no questionable ideas and decisions as on the most of guitar amps channels. You really do a great and beautiful work time after time.
Q1: the pot seems ok in that situation. Q2: I wanted the reference to stay fixed regardless of the mains supply, so that is correct. Q3: use the bigger pot. Q4: the built-in zener is fine to protect the source to drain connection, but I always use the zener to protect the source to gate link. I hope this helps 😊
I like it your electronics professor would give you an A on this project Manuel. The planning and particularly implementation is impressive. This certainly is a gift to the to the hobbyists that are involved with tube equipment. Might also be an interesting experiment to test a questionable old tube tester for calibration purposes. I’m going to have to look at x-ray Tony’s video on comparing tube testers to satisfy my curiosity.
Your better half let you have the big German radio in your living room because the grill cloth matches the sofa. Well how about a custom cabinet accentuating your wife’s tastes displaying her favorite knickknacks, with secret compartments for electronic storage.
Impressive build, love the front panel / lettering. I'm a stickler for detail (or pain in arse, whichever you prefer), and it's unlikely to ever be an issue, but I would earth the D-sub and valve bases and put a cap / boot on the mains toggle (just in case).
Prezado Manuel, saudações do Brasil! Parabéns pelo projeto interessantíssimo do medidor e pelos vídeos explicando a construção e o funcionamento. Tenho planos de construir um para mim.
Hi Manuel, almost finished my tester which is largely based on yours. I am having trouble with the LM338 heater circuit; the adjustment pin seems super sensitive and is near impossible to set at 6.3v (jumps up rapidly from 5.6v to 7.8v) I am using a 30v supply and have tried substituting a LM317 which works in the same circuit perfectly without alterations. Only difference to your published circuit is that it has an output cap of 10uF 50v and an adjustment pot of 5k and not 4k7. Any tips you could give would be great! Best regards, Phil
@@electronicsoldandnew Thanks for the reply, I have substituted the pot a few times even for a 1k but didn't work. Don't understand how the LM317 (1.5A version) works perfectly but the LM338 doesn't. By the way I am making vídeos about my progress on my channel (you have the credit). The HT side from your design is perfect and só is my DC bias using a LM337, just the heater circuit to go and I'm up and running!
@@electronicsoldandnew Thanks for the reply, I am scratching my head on this too, but I know there are a lot of Chinese fake chips on the market especially in Brazil. I'm probably going back to the UK this year (Brazil has a lot of political problems at the moment); so will have a much better selection of components in the UK.
@@electronicsoldandnew Helge Fykse has an interesting design and is able to test the audio of the tube using a 10 to 1 resistor divider at the output, inputting a triangle wave ot music at the grid (to listen to the tube under test)
Incredibly useful for a hobbyist what you have achieved, congratulations! What drawing software do you use for schematic layout of electronic components (Schematic_Tube tester V3_REV_1.2_2022-11-21)?
I separated the supplies because they are measuring voltages which in some cases have different grounds. I explained my reasoning in the videos, and cannot remember precisely right now.
Fantastic! This is something I can build and use. Will add it to my ever-growing list of projects. Could a Raspberry Pi or Arduino help to automate some of the adjustments, do you think? That could be an interesting add-on project.
Nice project! I have already ordered the PCBs. How much current do I need to test KT88, KT77, 6550 and EL34. Do you have any reckomendation for transformer specification
Thanks for answer i can see its possible to download the first 500 testcard for Funke. Is it possible to get the all cards up to 2211? @@electronicsoldandnew
Hello and thank you for your videos. This series about the tube tester, is the first one that I watch on your channel, and I apologize for my question if I should find the answer in some obvious place. Is there a video or other documentation available about the material that you used to build this cabinet? I don't understand what is it made of: I thought it was raw hardboard, but I am not so sure. Thank you for your attention. Regards, Daniele
Looking at te schematic v3 I reckon you need to recalculate R1. My numbers, reckoning on 345Volts at the positive end, subtract 255 for the zeners gives 90 volts. 18K gives a current of 5mA. That's about enough to bias the diodes but with 100k across it for the anode voltage there is another 2 1/2 mA being drawn. I reckon that 10K would be a bit happier. That will make nine milliamps available to stiffen the anode supplies and will still keep the wattage below 1 in the resistor. What do you think?
I experimented with various component combinations to try and keep the zener voltages stable, and this is the configuration that worked best. I don’t really like the zener stabilisation as there is quite a bit of fluctuation, but it’s the best so far.
Nice simple manual tester, really good PCBs and assembly :) I'm kinda perplexed by the whole B2+ regulator fed off B1+; I'd tie the drain to main HV DC and the VR-B2+ to B1+. Should give you back a bit of voltage drop on Q2 when B2+ is set to the max, at the cost of higher power dissipation when setting lower B1+ and B2+ voltages (more voltage dropping across the transistor).
The reason I did it this way was to prevent B2 from ever being higher than B1. In a typical tube circuit, the B2 is fed from B1 and is therefore always a little lower. B2 will be the screen grid voltage.
@@KeritechElectronicsIf I wanted a separate power supply for g2, would it be okay to use another printed circuit board, from the same transformer? Of course, I would take into account that g2 is not greater than g1...
Hello, I made your tube tester assembly, a very nice assembly and which works very well. I have a quick question about connecting a tube to the ECH81. How to make the DB 15 keys for this tube which includes a TRIODE and a somewhat special HEPTODE👍😇
The Funke card gives the following: Ua = +200V; Ug1 is the normal grid = 0 to -2V; Ug3&4 = +60V so treat this as the second B+ at 60V; and finally Ug3 = 0 so connect this to the 0V pin. Remember that Ug3&4 are internally connected to each other.
I was wondering if that IEC power connector on the side has a built in fuse ? I hope you have some inline fuse on that device someplace for added safety. Do you plug it into the isolated power supply when you use it ?
I knew this wouldn't disappoint. Just got to find some local to me to build one for me. Just out of curiosity what was a rough estimate of the parts cost?
@@electronicsoldandnew You could probably do that by interchanging k and A of the diode on your plugin, but with low voltage that doesn't exceed that of filament to cathode insulation.
Hi - great project with a very neat result. Something I should have asked a few episodes ago but just spotted again - why is the B2+ circuit slightly different to the B1+ circuit?
I added the transistor current limiter on the B1 circuit only because this is the one that feeds the B2. If there is a short on B2, it will draw current from the B1 and the current limit will kick in there.
congratulations for the project, very well presented and realized! do you have the .stl files from the housings for connectors?....can they be shared? thank you !
The limiting factor is the maximum current that it can supply, so it’s just a matter of checking the test current if the tube you want to test and ensure that it can be driven.
Bonjour, mon montage est presque terminé et j’améliore encore AVEC UN commutateur rotatif et trois pots 4.7kohm pour 4volts , 6.3 volts , 12,2 volts et changer R11 à 470 ohms
😇😀😀Ok Merci pour la réponse, c’est pour tester les lampes d’une radio qui ressemble beaucoup à celle que vous restaurez dans la vidéo ou la vitre est malheureusement cassée. Peut-être reconstituez-le comme un puzzle, placez les pièces sur de la résine liquide transparente de 1 à 1,5 mm si vous avez toutes les pièces.😀😇🤗
Hi great videos and have built my interpretation of your design using HV units in your first video. Have had mixed success, I suspect they do not supply enough current as am getting odd pulsing. But not important. I have ordered some of your board's form PCB way. I live in Spain but a mix up in delivery address has five sets going to the UK to my sister! My fault anyway ordered some more to come to Spain. So if anyone wants some boards in the UK I just want the postage costs to cover delivery in the UK. So if you know anyone who would take them of my hands let me know. Barry
Could add a small output transformer at the anode and couple to headphone, but that’s not in my plans at the moment. A microphone tube is easy enough to detect in the circuit anyway. You flick it with your finger and listen for the resulting sound at the speaker.
Manuel, I enjoyed watching your work on the tube tester. At the same time, I rebuilt my HV power supply. I used a few ideas. It's not ready yet, work is underway. Jacek Bochiński presented a very interesting story about the history of FUNKE tube tester (which you refer to). link ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-DedSugupbeY.html
