Homemade benchtop power supply

About my homemade benchtop power supply, which I built back in 1987, using an old tube tester transformer from 1951.
woodgears.ca/te...

[@sram993]

Hearing Matthias say that he can't diagnose/fix something reminds me of the feeling I got as a child when I realised my dad wasn't actually a superhero and couldn't do absolutely everything in the world. :-)

[@matthewphelps5136]

sram993 ikr

[@y788lhjk1]

hahahaha

[@pstrap1311]

As yes, I remember the moment of bitter disillusionment when I realized my dad was full of shit at least as often as not. However, Matthias' willingness to explaining his limitations is one of his best qualities, and in this case is very welcome. He's way smarter than me and if he can't do and understand everything then maybe I don't have to feel bad since I can't either. I'll just feel good about what I do know and can do!

[@matthiaswandel]

About my homemade benchtop power supply (which I built 28 years ago)

[@bno112300]

Matthias Wandel Only you'd make a power supply that goes up to 11.2.

[@sylvanenergy]

Matthias Wandel That is so coincidental, I'm making one right now. I just ordered a buck controller to run the fans. I'm rewinding the secondary to get what I need from a scrap microwave transformer. I am totally going to copy your case though....so awesome. Is that cap draining resistor on an over current relay too?

[@eiseklompstra]

bno112300 Well most blokes, youre on ten there, all the way up, where can you go from there? Where? Nowhere. What Matthias does, when he needs that extra push over the cliff, he puts it up to eleven.

[@gregorypeel5136]

Kale Klompstra Well it's one more now isn't it.

[@TheRealThisIsAlex]

Matthias why you dont put a Cooling fan in that bench power supply?

[@LarsonFamilyFarm-LLC]

I'm an EE...and I've never seen such a creative way to use a multi-tap transformer...you're entire power-supply is built around the "specialty" of that 1951 tube tester transformer. cool idea, cool project for HS no less is amazing.

[@maurocioffi]

The fact that you made this when you were in high school just confirms that you're a genius... when I was in high school the most difficult thing I did in my spare times was playing video games!

[@tomandalbert]

Great video. I spent a career as an ET. Keep it simple. You are amazing. Like the Brother Color printer my Dad brought home and said "you figure it out" I did. That was the early '80 and I programed that. And disassembled the print head with all them needles springs and pins. The shop he bought it from didn't know how to apply it. When he took those charts in with his sales data the president of the company wanted to know why they could not do this when Jack and his son could. I learned my electronics in the military and was an average guy and slow but methodical. The turtle. You are a great guy Mathis

[@tomandalbert]

Opps Matthias

[@donjohnson24]

Gosh, this really takes me back. As an apprentice, my original target job on completion of my apprenticeship was to be a 'valve engineer'. However, back around 1958, one of my sessions at the company works was in a section where they had just started to make germanium transistors, which eventually saw the demise of most valves. I remember looking through the window of the lab where they were growing the germanium crystal - I recall it looked like a two-inch diameter rough steel rod rising out of the retort at a very, very slow rate (something like an inch a week?) The finished rod was sliced into discs, and the disks cut into tiny squares. Blobs of N or P type germanium were fused to the square, with wires from all three coming out of the insulation surrounding the group in a container like a quarter-inch diameter little top hat. This was a transistor, and if I remember correctly the rejections rate (percentage that DIDN'T work) was initially something like 90%. Around this time, I made a one-valve radio - on a wooden chassis - and it looked very similar to your meter. I would guess that the soldering quality was also about the same standard! Thanks for the trip down memory lane.

[@matthiaswandel]

Don Johnson Wow, 2" wafers. I didn't know they ever made them that small! Saw "the post apocalyptic inventor"'s video of a frequency counter terdown (from the 60s). No wonder progress is faster now. The tools are so much better and cheaper!

[@pjhalchemy]

Matthias Wandel +Don Johnson Thank you both for the trip down memory lane. Haven't heard the term "Valve" since the mid 60's when I got into electronics. I still have a baby food jar full of old germanium transistors and diodes from the period. Also wish I still had my old RCA tube tester now that I've watched your video, Matthias. My first "O"scope in high school (mid 60's) was on wood and used a 3FP7 tube I scrounged at a surplus. Yours is an elegant & well thought out design, layout and wood working, although the caps could have been handled a bit better. ~¿@ Did you custom make that meter face too so it could do all 3? If you want another trip down the lane you might enjoy Fran Blanche and her Apollo DSKY display build...old school for sure and a great project. IMHO we shouldn't forget where we came from...that's how things got to be the way they are now and will get better from here! Thanks again! ~PJ

[@mrmroberts123]

I didn't understand any of the electronic explanation but still another great video! Thanks Matthias great work

[@MisterMooo]

Martin Roberts Here is an even shorter version (hope it helps): - The transformer (on the left of the diagram) reduces the mains AC voltage to lower AC voltages. - The different wires coming out of the right side of the transforrmer each carry different voltages. - The diodes (triangles) and capacitors (double rectangles) convert AC to DC (direct current) and smooth out the electrical output to provide steady and usable power

[@_deepinsee_]

Hi Matthias, I wish I could have had you as a teacher back in my university days (20 years ago). In this short video I have recalled a lots of information that I thought lost forever. You are indeed a really smart person and I can say it by the way you make so simple very complex concepts, you for sure have a true gift for teaching. Thank you for sharing.

[@rexpimplemyer3839]

This was pretty awesome. I like that you were able to re-purpose the tube tester parts. I'd love to find some of those again. In some applications they were way better than the digital/ transistor equipment we have now.

[@JayBates]

You first built that power supply a year before I was born.

[@finn127]

Jay Bates say what? I'm older than you?

[@JayBates]

FanteFinn I'm 28. Born in 86

[@lisakarabatsos8470]

Jay Bates if he built it in 1987, wouldn't it be a year after you were born?

[@JayBates]

Lisa Karabatsos In the video he said "I first built this power supply about 30 years ago in 1985"

[@lisakarabatsos8470]

Jay Bates my bad. I just went off his written comments. To tell you the truth, my brain was a little glassed-over on this one!

[@Xenro66]

My school had a bunch of bench powersupplies that were never used (literally not even once), so I mannaged to haggle for one. I had a look inside and it has the exact same style transformer. It doesn't have any capacitors or anything. It also has the +1 volt thing too, and goes up to 25v at 8 amps (200wp psu). Each step is 2v, so I have lots of resolution on it. Absolutely awesome psu.

[@TheDesertRat31]

I finally just watched this... Such a cool power supply. Really clever way to use that boost feature and what a great re-use of some old vintage tech.

[@Mosfet510]

I really like the case. What blew me away though was the date on the transformer, wasn't expecting that! Nice one.

[@felixthecrazy]

So basically your Boost is like going up to 11. ;)

[@Xenro66]

felixthecrazy 12%* :D

[@Martin_3D]

felixthecrazy yes!! These go to eleven!!!

[@killerpoopguy]

Jordan O'C If the thing being boosted was 10 maximum than a 12% boost would be 1.2 for a total of 11.2 or, about 11

[@-Sean_]

killerpoopguy precisely

[@ticijev]

felixthecrazy oh man!! :) I love the internet so much because of comments like this!

[@iPelaaja1]

That explanation was really good, quite in-depth, yet brief. Very simple and nice way to do an power supply. Too bad all this is thought at school, but nowadays, we don't actually build anything!

[@richardstewart4135]

Good work on a great little power supply! I have been an electronic tech since the 1960's and remember well using those old tube testers to check the many tubes we serviced in radios, and TV's of the period. I also remember an old timer I worked with that also used a multi-tap transformer from an old TV to make a similar power supply. Not as many taps, but it had quite a few and the supply worked rather well. These days, I use high performance lab supplies for my work, however, I have never forgotten the elegance of tube driven systems nor the ease at which an experimenter could build fun projects. Again, well done!

[@Bright8888]

Nice and simple power supply with lots of useful features! Reminds me of similar power supplies I built three decades back using multi-tap transformers, rectifier diodes and filter capacitors and no PCBs! Later, voltage regulator ICs were introduced and LEDs started replacing light bulbs. I have been into electronics for more than 30 years and into serious woodworking for the past one year. No wonder, I found this video quite interesting.

[@userunavailable3095]

You remind me of my grandfather, who was an electrical engineer and a woodworker (and of German descent). He had a lot of stuff around the house that was very similar, including a whole house stereo he built in the fifties, in which he built the cabinet of wood, and built all the electronics inside. It's like watching a younger version of him.

[@comictrio]

Simple but effective, nice job. I've been using used and discarded computer power supplies for years to power various projects that require, clean and regulated DC power. I collected 15 55 watt power supplies from some Sun Sparc workstations my company was tossing out. These make great 12 volt supplies for powering LED lights that I use and for powering a small array of cooling fans for my entertainment center.

[@HowToGuys]

Useful power supply, regid and thoughtful designed.

[@sirajhussain791]

Robust power supply, nicely built with good quality parts and excellent skills

[@PunakiviAddikti]

Old devices that don't use much semiconductors are quite fascinating. I built a aluminum case power supply with almost 0 to 35 volts range, that can be adjusted with a potentiometer. The potentiometer drives an adjustable regulator that in turn drives a very high power transistor to give more current on the output. It also has a digital current and voltage combo display and unregulated 35 volts AC out straight from the toroidal transformer, as well as an earth post that connects directly to the case and the earth from the power plug. It uses so many semiconductors I won't be able to list them all (there's so many on the voltage/current display). The display has its own power wires, and measures using voltage sensing wires and current sensing wires. That way it can read less voltage and current than it requires to run.

[@thuglviz]

Hey Matthias. I just want to say, that I realy love all Your videos. They are so informative, and You are the sharpest and wise mind in the yt river. Thanks for sharing.

[@elboa8]

My two hobbies are electronics and woodworking. It's not very often I see them combined in one video! Very old school, but it still works.Nice.

[@GarageWoodworks]

Commodre 64! I had one of those too plugged into a B&W TV. I learned basic on it.

[@vcsawduster5834]

Me too. Had a modem on my 64 and programmed fortran and cobal from my dorm room by dialing into the college mainframe at a baud rate of 300 in 1986. Awesome times.

[@GarageWoodworks]

Ha! I had a 300 too. Hayes modem? I can't remember. Used to dial into "bulletin boards", an early precursor to modern web forums.

[@matthiaswandel]

GarageWoodworks The "commodore 64" really defines a generation!

[@GarageWoodworks]

Matthias Wandel It really does! I wish I still had mine, but I think my dad tossed it after I left for college.

[@MichaelLaHonta]

GarageWoodworks Dorks! I ran that BBS software also.

[@mattriddlle100]

Matthias makes the best most descriptive videos, well worth the watch.

[@athiker7209]

Nice electronics class. I built one in college class, with a 24 vac transformer. I used the bridge rectifier and filtering circuits, but added some 2N3055 transistors to have regulated output. I used it for years to power my ham radios and to charge my 12 volt batteries. Years ago, my current meter went bad, so when I'm in need of a current reading, I just use my digital meter. You did a nice job on this project and the multi tap secondary of that transformer is nice for what you used it for.

[@kylevine4628]

I can't remember how i came across this channel, but i'm so glad i did. I'm a total timber nerd and even though everything in this video went way over my head, i still enjoyed it and hope that one day i will have a brain as full as yours

[@stevedoubleu99B]

Nifty little bit of kit, I like the AC capability and it looks good too.

[@jamesprigioni]

"My boy's wicked smart"

[@djAnakin]

james prigioni *smaht

[@ChemicalChrisOttawa]

Apparently you went to a better high school than me, lol. Well done! Recently built one myself, but used an old computer ATX power supply, gives easy 3.3, 5, and 12v DC. Can do others (like 7v, connect 12 to 5, not great for the PSU but works fine more or less). Paid 5 buxs for PSU, a few more for some buck boost converters, as well as current limiting boards, all told under 50bucks, easy to put together, and much cheaper than an off the shelf unit. I would like to be able to play with AC to, but this is suitable for now. Still, this was sooooo much simpler than your project, so again, well done!

[@dougankrum3328]

Very nice power supply project....that transformer and multi-pole switch would cost a small fortune today...!

[@raymitchell9736]

This is a very cute power supply, you said that you didn't include a fuse which is something that brings back memories when I was in high school too... (but I'm fuzzy on the details) that when I had on a home-built power supply with fixed, unregulated 6 and 12 VDC it had a slow-blow 3A fuse... But when playing with it, accidently at times I'd short it and the fuse blew, replacing it was always a pain... and if I didn't have a fuse I just bypassed the dang thing. So I came up R/S flip-flop design with transistors, and maybe I had a relay with high-current contacts, that would drop out when the current went above a certain threshold and kill the power to the contacts, I could reset the system and get back to business quickly, And it added functionality, because now I could energize my project with a press of a button and I could quickly turn it off all while leaving the banana plugs in the power supply connected to the project. My design had two momentary pushbuttons for ON(Reset) and OFF, and two LEDs: A red LED was off/overload and a green LED was Power ON. In retrospect, I could have added a potentiometer to adjust the threshold to where I wanted the "protection" circuit to trigger... I just made it fixed for the maximum current. This was better than a fuse and it added functionality and a little bit of safety to the power supply... oh... and it required a lot of fun tinkering to get it to work just right. Cheers!

[@das250250]

Fantastic little power supply . That transformer wouldn't be too common to find second hand :-) . I love the AC / DC choice .. very handy

[@ChrisSmith-yx1iu]

I dig the blinking effect , adds a real first person view.. i hope im not the only one noticing a slight blink when focusing ..lol anyway that thing i bad ass and you sir are one hell of a smart man!

[@charleyandsarah]

You are too cool for words. Very neat features.

[@JCHaywire]

My favorite of your whole oeuvre. You're so much like my grandpa, who worked for Collins Radio in Cedar Rapids. He had a really practical style. Austere, but really competent. This piece is amazing.

[@jamiecollins4329]

Matt very knowledgeable on the avionics and I enjoy watching your woodworking videos, multitasking now. Thanks and well done.

[@Rouverius]

Clever getting full usage out of that transformer. Actually, the extra tap on the supply coil was a surprise to me. But it makes sense if they were shipping that tube tester internationally; a number of countries outside of North America are using 110VAC or 100VAC.

[@modziasx]

So simple, but so nice at the same time. And what's most important: it's doing its job!

[@Skipperj]

Awesome job Matthias! I saw an old tube tester on Craigslist the other day for $20.I had no idea. I will be on the lookout from now on and will look at the old with a renewed motive. Thanks for inspiring me, Skip J.

[@SuburbanDon]

Love the pilot light. Things were simpler back then.

[@tubelilous]

Thanks for sharing. I did a substantially similar project in high school. The schematic brought back memories. We had put in a digital display and variable pot for output adjustment. Mine lacked the v110 output though which seems very convenient.

[@richard7crowley]

Alas, here in the 21st century it would be easier to find a pot of gold vs. finding an old tube tester with an amazing transformer like that. Besides, these days, one of those vintage tube testers would be much more valuable than an equivalent new transformer (if they even still made them like that). A modern equivalent for AC could be an ISOLATED Variac which outputs a continuously variable voltage. But this is a lovely example of how to make a piece of DIY test gear that is functional and presentable. I still have some DIY test gear and gadgets and tools that I made as a kid and still use nearly 50 years later.

[@matthiaswandel]

yes, the irony. But back in 1984, things were different.

[@Jono6671]

man I love this old school electronics stuff- REAL stuff :)

[@Garageworkshop]

Thanks a lot for explaining how it works. I really need to learn more about electronics this summer.

[@saturn5tony]

really nice design of a power supply from an old tube tester!

[@dlwatib]

Maybe some day we as a society will finally learn that more complex isn't better. Simpler is better.

[@Neilrrc37]

Your wooden case is fabulous. I assembled one last summer using blocks and pins, cause I don't have a router. My project box isn't exactly square, it's out 1/16" inch in the corners, and other places. Mind you, that's the best I could do with a Dremel Multi Tool.

[@michaelgasperik4319]

That is a really nice power supply. I too, prefer old electronics to new. I can understand and use newer technology but the old way of building things just works better. Transformer from 1951 still working versus transformer from a Sony home amplifier from 1997 that recently and randomly just stopped working. They just don't make'em like they use to.

[@telstarvision1509]

what a brilliant peice of kit , I love all of these oldy worldy projects & I am very interested in building stuff of a similar style & design.Full marks to you for your ingenuity it's a credit to you.cheers

[@karlkelley9103]

WOW...thanks for the memories, Matthias. Are you sure you're not the same age as me (67)? The electronics is a great design and I miss the simplicity of the older electronics. Do you still an interest in electronics? ...if so do some more electronics stuff for us woodworkers who have an electronics interest.

[@taunteratwill1787]

Karl Kelley Unlike you, he was never sure about his age

[@genericchannel2]

"One is full voltage, and one is a little bit more" Just excellent.

[@GlassImpressions]

Your knowledge amazes me!

[@sbrunner69]

cool! this is by far my favorite channel

[@Lutranereis]

And here I'm just using an old computer PSU as my bench power supply. It only does 3.3v, 5v, -5v, 12v and -12v, but it's more than enough for the small projects I do.

[@MsSomeonenew]

Lutranereis You can also bridge those to get stuff in between, 3.3V to 5V gives a 1.7V difference, 3.3 -> -5 = 8.3V, 3.3 -> 12 = 8.7V, 3.3 -> -12 = 15.3V, 5 -> -5 = 10V, 12 -> -12 = 24V,... so on and so forth. Just be warned only thick wire 5V and 12V are made for heavy loads and protected, everything else is for basic circuit work and might crap out if shorted.

[@Lutranereis]

MsSomeonenew Huh! I honestly never thought about that. I only really dabble in electronics anyway, but if I get more serious in the future...I'll probably just buy a proper benchtop supply. XD Still, it's good to know that, in a pinch, I can do different voltages. Seriously, thank you.

[@rodswim91]

More useful than many university classes. Thanks

[@tomallen3605]

I built my first 12 volt dc power supply using a vacuum tube rectifier. I used it to power a car radio/tape player in 1971.

[@HDInstrumental1]

Handymen such as you are extremely rare nowadays. :)

[@cme1ca]

By the look of the robertson screws and the C64 plug, I'd say Matthias went to school in southern Ontario. Nice PS Matthias.

[@mapleleaf4ever]

That's a fine piece of hardware you built! Nice job!

[@eduardoalcantarajr3668]

Wow i'm just like yours a woodworker at the same time an electronics geek, great combination, as woodworker its so much fun to build speakers for amplifiers.

[@SadamFlu]

Yeah you'd understand! You're incredible Matthias!

[@neversaynever5157]

Great video , excellent work making that power supply . It has a huge history thanks for sharing with us

[@TheZooman22]

Nice to see you have made good use of it.

[@joangelafrankwood2643]

geez man. are you some kind of wizard or something?? you are freaking smart. love your videos.

[@CassetteMaster]

This is a very nice, and well-done, beautiful device.

[@rominhawk3949]

Thank you Mathias, as with all your videos, just superb quality, explanations.

[@johnconrad5487]

it is really beautifully packaged. thanks for sharing. the ac output is a great idea. i immediately started thinking of how i could add that to my p/s.

[@christopheleblanc9175]

tks for the memory's of high school (12) digital electronics lol AM FM stereo build , worked up till 2 yr ago when i gave to a e-recycler friend who did not scrap it ,,, he put it in his shop lol replaced a fuse ,,,

[@mlindholm]

That is pretty awesome, thanks for going into the depth of explanation you did!

[@JoeGP]

you got lucky with that transformer, unfortunately most transformers are no where near as versatile. And apparently you look a lot younger than you are, you built that the year i was born

[@matthiaswandel]

Joe G.P. I built that power supply because I had that transformer.

[@viermidebutura]

Joe G.P. is not that hard to re wind it....

[@38911bytefree]

Joe G.P. You can still use a 1:1 ratio tranformer (for isolation) and then a Variac and get "infinite" taps, rough and simple. None of them are cheap, of course. The Mathias transformer was really a nice find.

[@JoeGP]

38911bytefree I found one that outputed 2, 4, 6, 12 and 24 V (all at 5A) but i also built a small board for a variable 1.5-30V/1A, it also had a 110V AC out which was handy (we use 220V)

[@parleyk4503]

An audio amplifier transformer has many taps like that tube test transformer they would be great for similar projects

[@mike_van_in]

Very cool vintage project!

[@peterowens290]

A fine example of ingenuity for 1984. I think today we would approach an equivalent build differently. You can buy an adjustable 24V 10A SMPS for maybe $40/50 & go from there.. The woodwork is good but ergonomically I would attempt a sloping front to make things much easier to read.

[@stevev2414]

very cool. Reminds me of a similar power supply and oscilloscope that I built - also many, many years ago. However, I still have yet to find a 'woodworking' use for the oscillioscope!

[@SPEAKERSRULEMYWORLD]

Beautiful little piece

[@bwack]

That is a work of art !

[@w8fg]

Interesting supply, i like it! Bet its hard to get a clean transformer like that now. As an ham radio tinkerer I could see much benefit in your design.

[@Mark-ej3oi]

A bench power supply is not only supposed to supply a DC voltage but to supply it cleanly! From what I can see from the primitive filtering of your power supply the ripple there should be massive!

[@mspacone]

Brilliant! I've always wondered what that looked like inside - thanks!

[@FavioRamirez]

Thanks for sharing! Awesome and creative features! The 12% boost is great!

[@GeorgeGardinier]

really good, that is better than the switching ones out there now. did i hear it was only 3 amp. now to add some fuses or resetable breakers, good to keep around for ever

[@iamdarkyoshi]

Nice job! My programmable switchmode supply is being a butt and I do not have time to troubleshoot it. You should make a second channel with electronics projects for those interested..

[@JeremyMcMahan]

Great explanation. Enjoyed the break down.

[@dzolotas]

Simple, clever, efficient. Very good!

[@tractyzadorozny2972]

That is better than many things you can buy today

[@Barnekkid]

Nice workmanship.

[@billyjoe3309]

Love your work Matthias, you are very clever!

[@ClarksonFisherIII]

awesome! I want to eventually learn about electronics and your video is inspiring.

[@JasperJanssen]

12% sounds almost like you've got a primary winding that can be switched between 110 and 120V.

[@DBYNOE]

Wow, that transformer is older than me by several years, that supply is still working, a testament to the quality of your work even so long ago. You have done some motor electronics before, your explanations are really clear and engaging, you should do more. Is there anyway to tell if viewers were bailing out before the end?

[@edwardholmes91]

If you go into the stats of your videos, you can see average viewing times and things I think.

[@melplishka5978]

Great design, well done.

[@johnbhancock]

Great video thanks. As an old electronics TO myself I was really interested in how you made it. I too have made my fair share of bench top PSU but never with a wooden case :)

[@ephemerlol]

I would love to see more videos of odd electrical knick-knacks you have built!

[@lindyfd1606]

My think-bone hurts. Really cool stuff.

[@Robonza]

Nice simple design. its just missing the ground on the transformer core.

[@ZeedijkMike]

Good old PS design, as we made it when I was young(er). You hardly ever see these multi tap transformers any more. I guess because of the switch mode supplies. But this design is more than adequate for most purposes and barely contains any parts that can fail. Of course it would be safer with at 3-4 amp fuse at the output.

[@melplishka5978]

I love older transformers. They were made too last and made multi usable lol.

[@mfwoodshop]

Cool I made one in school myself I still use it. But I got dumb over the years don't know if it could diagnose it now or not

[@CharlieTechie]

Very nice design, good video. Thanks for sharing.