Building the Largest 741 OpAmp in the World with Vacuum Tubes (Plus 555 Timer Update)

[@LOOKMUMNOCOMPUTER]

haha imagine an alternative dimension where these IC sockets were the standard size ha

[@UsagiElectric]

Now that's my kind of atompunk science fiction! I'm actually quite happy with the new, smaller form factor, I'm going to see if I can design more ICs that fit in that form factor and socket!

[@winstonsmith478]

Sheldon: I recently had a dream that I was a giant. But everything around me was to scale so it all looked normal. Leonard: Well, how did you know you were a giant if everything was to scale? Sheldon: I was wearing size a million pants.

[@coll1208]

Usagi: The biggest IC socket in the world! LMNC: Hold KOSMO...

[@KennyNunnSax]

If system on a wafer becomes affordable, large connectors might make a comeback. Probably not in this form factor though 😂😂

[@RK-1956]

This a really interesting retro project. It reminds me of when I started learning electronics back in the late '60s. My first project was a 5-tube stereo amplifier. Drove my parents crazy :-) On your 555 timer... @3:56, you can tell by the dips in the solder, that the solder really didn't "wet" or adhere to the aluminum leads/legs. This creates a higher than zero ohm connection. Just maybe, this additional resistance is in part why this version of your 555 is not working as well as you hoped.

[@UsagiElectric]

Thank you so much! That's awesome that your first project was a 5-tube amplifier! That's so much more impressive than my first project, which was a little FLED photopopper BEAM robot, haha. For the 555 timer, it actually doesn't work because of a massive oversight when I was trying to minimize the tube count - I inadvertently changed the two OpAmp/Comparators from inverting to non-inverting, which totally messed up every other aspect of the design. It worked really well in astable mode and as a schmitt trigger, but would absolutely refuse to work in monostable or bistable modes. Oops! So, the next redesign is in the works. I do have really great continuity between the legs and the pins (like less than 1 ohm), so perhaps I got some adherence to the aluminum legs a little deeper, but it was such a bear to solder, that I'm working on figuring out how to change over to having legs like on the 741 made from PCB copper. These are so much easier to solder and should still be plenty rigid. Just gotta figure out how to lay out the gerber file correctly!

[@stamasd8500]

@@UsagiElectric For soldering aluminum, usual electrical tin/lead solder doesn't work too well. There are special solders that work a lot better on aluminum (and still work well on copper too, so you can make aluminum-copper joints). They are usually tin/zinc solders, but the downside is that they melt at higher temperatures so a regular soldering gun will not work with them. They come in various compositions, from 60% tin/40% zinc which melts at 635F/335C, to 91% tin/9% zinc which melts at 390F/200C. You can also use indium which works very very well and melts at 156C, but that is very expensive (about as expensive as silver).

[@Westfalon]

Words cannot describe how much I want to run an electric guitar through that........

[@UsagiElectric]

That would certainly be cool! It would need a little bit of work to hear anything because even though it's got a buffer on it, it's still far too high of an impedance for a speaker, but it would be really interesting to see what it ends up sounding like!

[@Westfalon]

@@UsagiElectric oh of course. I wouldn't expect those little guys to drive more than a watt into a speaker. But as an effect or pedal it would be very interesting. A literal tube screamer!

[@frankowalker4662]

The 555 kit looks awesome. The 741 works realy well and I love the socket. You are a master crafts-man. :)

[@UsagiElectric]

Thank you so much! I'm really happy with how the 555 kit is turning out! Now, I just gotta get it working, haha.

[@weirdboyjim]

Great Video! Are you thinking about switching to the pcb legs for the 555 design? Just a thought but you could potentially build a "socket" using edge connectors on a PCB.

[@UsagiElectric]

Thank you! For the time being, the 555 design will keep the aluminum legs, but that's primarily because I already have a bunch of them that I ordered, haha. Also, they're very rigidly mounted, and I'm a bit partial to the strength they have. But, I'm really liking the smaller form factor IC design, so I'm going to work on trying to build more ICs in that size too. I may even be able to stuff a 555 timer into that tight package with the help of some dual triodes. I like that idea of using edge connectors! There's lots of ways that could be expanded out to actually make these designs a bit more usable without having to build a socket using some scrap wood and metal flashing, haha.

[@simonkormendy849]

That waveform distortion we see, where the Sine wave changes to a Triangle wave, is called Slew-Rate Distortion, it's mainly due to the fact that the output can't change fast enough to be able to reproduce the input-signal waveform, Slew-Rate is a specification that all Op-Amp ICs have and is measured as a change of so many volts per micro-second, or nano-second, the greater the number of volts per micro-second, or nano-second, the faster the Slew-Rate is, for a good quality Op Amp IC, it needs to have a very fast Slew-Rate spec.

[@UsagiElectric]

Yup, a few other viewers let me know that's a slew rate problem! It definitely stems from the feedback circuit, which I need to keep the whole thing stable enough to be usable, but it places some pretty heavy limitations on the frequency range. Fortunately, I'm not trying to build a high quality OpAmp, I'm instead going for "does it kinda sorta work?", haha.

[@simonkormendy849]

​@@UsagiElectric The fact that it works as well as it does is quite impressive, and yes, the feedback circuit will have a limiting effect on the slew-rate, I found this quite fascinating, recently I built an OTL (Output Transformerless) Headphone Amplifier using three Svetlana 6N1P tubes based on an article I found on the Headwize Memorial website, it runs the three 6N1P tubes off of a simple power supply that generates 6.3V DC @ 2A, and 306V DC at 115mA, it is designed to directly drive headphones down to 32 Ohms impedance via two 470uF/450V DC caps, it sounds wonderful and plenty loud with my Audio Technica ATH-M50X headphones that are rated at 38 Ohms, audio is crystal clear, frequency response is virtually ruler-flat from 10Hz to 100kHz, I had loads of fun building it.

[@cairsahrstjoseph996]

I wonder if you can wire in that vacuum tube 555 in place of an IC in something modern and run it like that, for a lark.

[@UsagiElectric]

(YT seems to have lost some of my comment replies, so if you're seeing double replies, it means I truly don't have a clue what YT is doing anymore, haha) I've actually thought about this before! There's a few things holding us back though. The primary one is power supply. The tube version needs +24V and -12V, which is pretty far outside what the silicon 555 expects. The second issue is input impedance problems. On the silicon 555 you can just much smaller resistor values for setting up the various modes (like 1k, 4.7k, 10k, etc.), but the tube version needs much higher resistor values to properly work (100k, 220k, 470k, etc.). Still, it hasn't stopped me of dreaming about trying to figure out how to get a tube version in place somewhere though, haha.

[@cristianomaker]

Really amazing! Love the wooden "socket"!

[@UsagiElectric]

Thank you so much! I'm super happy with how the socket turned out!

[@Jenisonc]

Yep. You are a mad genius. This is so freaking cool.

[@UsagiElectric]

Thank you! I don't know if I'd say "genius" though, I'm just a little crazy is all, haha.

[@willjackson1955]

LOVE IT! Now you could try, for example, a LM386 audio amp IC. It would be cool to see tubes being used in conjuction with a small output transformer, giving maybe a watt or so in class A. Theorically you could built it with subminiature tubes, especially soviet ones, to aid in shrinking it to a smaller size. Marvellous video, as always, keep up this amazing work!

[@UsagiElectric]

Thank you! Oooh, now that is an interesting idea! I have these tiny little output transformers designed for 8 ohm speakers that could work perfectly too. Hmm, I would have to sacrifice a pin to get my -12V into the circuit - perhaps the bypass pin can be sacrificed. I'll also have to give a think about how to get the gain pins set up correctly too. But I do like this idea! And I'm pretty sure I can still fit it in the same package size! That's definitely going on my list of ICs to replicate!

[@willjackson1955]

@@UsagiElectric Thanks, glad to see my suggestion was interesting to you! Still, please try and use cathode resistors! It's ohms law and a few more steps, nothing more I promise! Ditching the -12v supply would solve loads of problems! Less power used, a pin less in your sockets being used by the power lines, better adjustability for various tubes (being self biased makes them immune to aging!) and so on... Also, have you heard of analog computers? Using a bunch of tubes to build a few of your op amps would make then useful for simulating something as complex as a car suspension for example! For a quick start guide check the "EAI Analog Computer" on youtube, it's the video with the violet thumbnail and the letters E A I in capital, you can't miss

[@UsagiElectric]

@@willjackson1955 I've actually done a lot of testing with cathode resistors, trying to eliminate the need for a negative bias supply, but I've never been able to get it working correctly. Perhaps I'm butting my head up against the low voltage aspect of it, or (more likely) I'm just not quite smart enough to figure out the right values, haha. In the case of the OpAmp though, I'm actually just copying the Philbrick K2-W design, which uses +300V and -300V. I've also looked a lot at the Heathkit EC-1 OpAmp design, but they also use +300V and -150V, so I'm not sure if there's a good design out there for a tube OpAmp that eliminates the need for a negative bias supply. And speaking of the Heathkit, I have indeed heard of analog computers and they absolutely fascinate me! I would love to try to build a low voltage version of one someday! I think it would be really awesome to build one to simulate the bouncing ball problem on a scope (and then maybe build a dedicated scope and CRT for it at some point). I hadn't seen that EAI video yet, so it's on my bookmarks to watch later tonight, thank you for turning me on to it!

[@dbingamon]

An LM386 would actually have some practicality to it.

[@hamster9135]

I'm loving these humongous ICs and sockets. Really interesting, and I've learnt some things too!

[@UsagiElectric]

Thank you so much! I know it's not super practical to build these out so they look like scaled up ICs, but it sure does look cool, haha.

[@tubeDude48]

Yes! Make this a kit!!!

[@UsagiElectric]

I'll get to work on a proper design for it! Thank you!

[@nickk6109]

Nice! I have a project that uses VHF tubes in op-amps that I'm developing. I'm lucky that the system has ±320V available but the RF means being more careful with the resistance/capacitance or the frequency responses suffers.

[@UsagiElectric]

Thank you! Yeah, having higher voltage really helps with the OpAmps, particularly in getting enough gain out of a single amplifier stage. Still, tube OpAmps are so much finicky than their solid state counterparts! But, that's part of the reason I find them so fascinating I think, haha.

[@richardatanacio4049]

I've replicated the oldy RC4136 Op Amp using 2N2222A discrete transistors, 2SA907 Transistors as low noise input, and 2N5458 JFETs as biased circuit, out of curiosity and it' s functional. Inspired by your creativity, I wish again I can build a bigger version of LM1875 using vacuum tubes or high- speed types of semiconductors. Thanks for nice video.... From Philippines

[@UsagiElectric]

That's awesome that you built a discrete version the RC4136 OpAmp, that's a serious undertaking! My tube 741 here isn't really a 741 replica, but more of an 8-pin oversized DIP nod at the chip and its significance. It's actually much closer to a Philbrick K2-W replica (with a few changes to work at lower voltages). That's awesome that you're looking to build a replica of the LM1875 too, definitely keep me updated on the progress of that, that sounds like it'll be really epic!

[@andymouse]

Love it ! and the socket !....cheers.

[@UsagiElectric]

Thank you! The socket turned out way better than I had hoped, I'm super happy with it. Now, just to build a larger socket for the 555 project...

[@travishein]

You pick the best groove music for the built montages!

[@UsagiElectric]

Thank you! That Megaman jam really works great for montages!

[@DavstrWrexham]

I'd love to see one of the 74 series logic chips done this way was well.

[@UsagiElectric]

Ooh, now that's a cool idea! Something like the first 7400 quad NAND gate would be very cool indeed!

[@vladislavdamqnov2072]

Hmm, try substituting the cathode resistors of the differential amplifier pair at the left of the circuit with a constant current source, and try not to push the tubes to run so low on current. Different parasitic capacitances will distort the signal even at fairly low frequencies. I'd design it to run at higher voltages and current, maybe use a cascaded voltage amplifier stage to get the most out of the available gain (or a bootstrapped stage instead). And most importantly, use a constant current source instead of the 470k resistors.... That should make most of the difference.

[@UsagiElectric]

I think you're on the mark that the biggest drawback of this design is that it's running on such an incredibly low voltage. It's actually a pretty direct copy of the K2-W OpAmp design, but that one was meant to run on +300V and -300V, so with just +24V and -12V on tap, we're going to hit some hard limitations. But, I'm actually alright with those limitations! It's an ultra safe way to experiment with vacuum tubes, especially if this becomes a kit in the future!

[@danielivkovic-mc7lr]

I wonder if these in an audio circuit would "sound" better than transistor ICs?

[@ropersonline]

The problem with the idea of using a higher temp and special solder to attach the UE555's legs is that if this is to become a kit, not everybody has that extra stuff. It might be a better idea to design a mechanical, screw-on connection whereby kit builders solder smallish pieces of metal, maybe appropriately formed and conductive washers, onto the PCB, and then the legs themselves are connected mechanically, i.e. each leg would come pre-bent, with a lip that's drilled and threaded, so they can be screwed onto the conductive washer-reinforced PCB via conductive screws, perhaps even in a three-hole triangle for extra stability.

[@akkudakkupl]

Cool project! One thing though - that aluminum is not soldered - aluminum is unsolderable with leaded solder, and you need some agressive flux to pull it off ;-)

[@UsagiElectric]

Thank you! Quite a few people have let me know about the aluminum soldering. It is very solidly in place and actually makes connection, but the solder joints don't look quite right, so I'm inclined to not trust it. I've actually been working on redesigning the legs a bit to solve this issue (something similar to what the 741 is using, as that one soldered up beautifully). It's kind of a shame though because those aluminum legs look amazing, haha.

[@akkudakkupl]

@@UsagiElectric The PCB legs on 741 look great IMO, use a tinning solution to cover whole PCB with tin (Make PCB Tinning Solution ("Liquid Tin") by Redox Flipping - NurdRage video gives an example of how to do this) - it will look just as good ;-)

[@JenkinsUSA]

The PCB board legs are the way to go. 💪 - yes on the op-amp kit 🙌

[@stphinkle]

Connect your vaccum tube 555 to your vaccum tube 7.1 with 24V on the input and then send the output to the counter input of the tube counter. If you use a gain of 3.3 on a 24 volt pulse going in, you should have 80V on the output.

[@UsagiElectric]

I'm right there with you on this! Though, I'm more imagining a dual triode redesign of the 555 to fit in the same DIP form factor as the 741, then building up a few different extra-large 8-pin ICs, and then making the biggest PCB in the world with socketed tube ICs! It would be hilarious, but also make for one of the coolest things in the world to hang on the wall!

[@winstonsmith478]

Very cool on both devices, but on the kits I'd like to see the addition of a more conventional way of attaching leads, maybe press to open speaker lead connectors or something else that similarly maintains a "hollow state" era retro look.

[@UsagiElectric]

Thank you! That's actually a brilliant idea! I think I'm going to use some screw terminals because they're cheap and super compact, so can easily be stuffed on the board. But that should definitely make it a lot easier to hook some wires up to the pins without needing a bunch of alligator clips!

[@richardmilward7478]

Use fahnestock clips!

[@UsagiElectric]

@@richardmilward7478 Oooh, those are cool little clips indeed! I don't think I have enough room to fit them on the PCB here, but I'll definitely keep them in mind for future projects!

[@grahamheath3799]

This reminds me it was probably late 1970s I was working on ageing analogue equipment 1 unit had a aluminium enclosed module about 3.5 inches by 1.5 inches perhaps an inch tall. mounted on the motherboard PCB via screw terminals it was an discrete component OP AMP. later versions had the same motherboard with a PCB containing a 741 and a couple of resistors. When opened the module it was almost filled with vertically mounted components. I wish I had kept one.

[@nicholasmaude6906]

Perhaps you could create a version using sub-miniature valves instead.

[@tukangbobo]

love it, yes! please make it a kit.

[@UsagiElectric]

Awesome, thank you! I'll get to work on figuring out a good way to get the legs manufactured and then this one will become available alongside the 555 timer!

[@MB-st7be]

You can tone down the 'ha ha ha that's ha ha ha awesome ha ha ha". It gets a little wearing after a while.

[@UsagiElectric]

I'm sorry that it felt grating! I do genuinely get really, really excited and happy about this stuff, but it's really hard to convey the joy I feel inside to the camera, especially when it's just my voice. So, I try to be as absolutely vocal as possible. Sometimes it may come off as sounding disingenuous or fake, but I assure you, everytime I'm laughing and saying it's "awesome" on camera, I truly think it's awesome! I went to University for language and this whole electronics thing is pretty new and fresh to me, so when something finally works, I can't help but feel like a rockstar!

[@chrismulhauser333]

I kinda wanna make a socket connector for it like 3D printed with metal strips as the contacts like a breadboard

[@Bleats_Sinodai]

Time to make a giant distortion pedal 😀

[@UsagiElectric]

Here at Usagi Electric, we build stuff for giants!

[@marcsmithsonian9773]

I am wondering if you tested how it sounds in audio applications? The idea of multiplybstages should add some even harmonics... if so I can see your kit to gain popularity. I would buy few, but I preffere to more practical rather then show of ,.so ne legs would be better, also its size can be reduced perhaps even use nuvistor or sub mini pentodes ( some russian seller offers them on ebay in bulk) Good Luck !

[@UsagiElectric]

Thank you! I haven't done any testing in an audio sense with it, but I do think it would be really interesting! With some dual triodes like the 12AX7 or something, ti could be brought down in size quite a lot and made into a more practical layout for use. Though, it would need an output transformer of some type as it's still way too high impedance for a speaker, and with only 24V on the plate, there's not a whole lot of power. But, it would certainly be interesting to see where this design could go in terms of audio!

[@JenkinsUSA]

Love it!!! I’ll buy the 555 kit 🔥

[@TatuWikmanFI]

So where can I preorder the 741 kit :)

[@UsagiElectric]

As soon as I figure out how to get JLCPCB to cut out the legs from some PCB stock and leave the entire leg exposed (as well as figure out how to make them break away, so they're not floating around all loose). I've got some more PCB software learning to do!

[@MagicGumable]

Awesome! Still waiting for the EF80 Conversion ;)

[@UsagiElectric]

Thank you! As soon as I get the 6AU6 version working correctly, it's time to start designing the 9-pin pentode version!

[@richardmilward7478]

Next, make an all hollow-state fuzz pedal!

[@UsagiElectric]

I know so little about audio stuff, I had to google fuzz pedal! That would definitely be something fun to build, but I don't actually have any way to test it, we don't have a single guitar in the house!

[@adamkekow6558]

Is It posible to build current source and current mirror with tubes? 741 uses active load to enhance gain and convert diferential otput to single ended.

[@AustinArto]

Your opening credits: Is that a Creed 55 teleprinter I hear?

[@cb314]

I like computers and guitars. I would love to use this to make a Distortion Plus guitar effect with this 741 tube IC!!!!

[@amoddev3483]

Where do you get ur vacuum tubes?

[@TastyBusiness]

World's largest functional DIP socket.

[@UsagiElectric]

I like my electronics to be big enough to see without glasses, haha.

[@Karamazov9]

This is so cool

[@bobkane1396]

That's awesome.

[@MultiPetercool]

Would love to see a hollow state analog monophonic synthesizer based on your op-amp modules. 😜

[@monochromaticlightsource2834]

Next project, varactor diode controlled capacitor switching for the gain adjustments.

[@jeffreysottos8648]

I want one! (maybe 3 ) are the 741 op amps going to be available for purchase

[@maxs.3238]

That's it. I'm subscribing.

[@UsagiElectric]

Thank you so much!

[@ropersonline]

19:40

[@UntrackedEndorphins]

Can the final product have rounded corners? that'd be nice :3 edit: nvm I just noticed it does have rounded corners lol Also, the legs could be copper or brass, or even PBCs with plated edges, It would be easier to solder them. And maybe they could have some holes on them to attach alligator clips, kind of like the BBC:Micro boards

[@UsagiElectric]

Thank you for the ideas! The rounded corners thing is something I didn't do on my original 555 timer build, but I wish I would have. Almost all of my stuff is getting rounded corners now, it's just so much nicer! I do really like the idea of using PCBs for the legs. If I can come up with a good way to order that from one of the PCB manufacturers, it'll make life a whole lot easier. But, I think I'm also going to add the ability to solder in some screw terminals for each pin. That way wires can be screwed directly in place for anyone who doesn't have a bunch of alligator clips or a ready made massive DIP socket.

[@UntrackedEndorphins]

@@UsagiElectric You could order the legs on a panel, since they're so similar to each other, it would also make the overall cost lower

[@UsagiElectric]

@@UntrackedEndorphins I definitely think this is what I'm going to do. I just gotta figure out how to get the Gerber files laid out correctly with the proper copper coverage and break away sections. Time to do some Googling!

[@DAVIDGREGORYKERR]

What about TELEFUNKEN Space Charge Vacuum tubes.

[@UsagiElectric]

I believe there were actually a couple different manufacturers that built space charge low voltage vacuum tubes. Tung Sol and Sylvania both produced a version of the 12U7, the 12V version of the 12AU7 I believe. Honestly, I would love to try out some of these space charge tubes and pit them up against the venerable 6AU6 and see how they perform! Unfortunately, they're pretty rare and a little pricey. One of these days though, I'll make a proper shootout video!

[@mikegLXIVMM]

I didn't even know you could solder aluminum.

[@UsagiElectric]

It's not easy, but I found I could get good connections if I got it hot enough! A nice wide tip and a 40 watt soldering iron with some good 60/40 solder seemed to do the trick!

[@Sine1040]

You can, but with special solder/flux otherwise the aluminum oxide layer prevents the solder from even touching the aluminum. But the joints on the 555 board don't really seem to have wetted the aluminum.

[@UsagiElectric]

@@Sine1040 Yeah, I'm not sure how much of the solder has stuck to the aluminum, because the solder joints do look a little different than I'm used to. But, the legs are very strongly mounted on there and I've got great conductivity between the legs themselves and the pins on the board! The reason the 555 timer doesn't actually work at the moment is because I made a dumb oversight when dropping the number of tubes - my OpAmps changed from inverting OpAmps to non-inverting OpAmps. Weirdly, it still works beautifully as a Schmitt Trigger and as an Astable Oscillator. But, it absolutely refuses to work in Monstable and Bistable modes. So, a bit more redesigning is required!

[@ahbushnell1]

With this opamp you could build an analog computer

[@Madness832]

The tube six-pack is off-center. That's messin' w/ my OCD a bit!

[@UsagiElectric]

It's off-center by exactly 6mm, and to be honest, I never really noticed before, but now that's all I can see, haha. Unfortunately, the limiting factor is the output jumper to get the buffered output up to pin 6. I might be able to shuffle around a few traces to make some room, but in the meantime, I'm going with the excuse that it's off-center so it's easy to figure out where pin 1 is!

[@jensschroder8214]

Besides that a real 741 is extremely cheap and a 358 is just as cheap and better. Apart from that, a great idea. Maybe to understand how vacuum tubes work.

[@UsagiElectric]

Oh absolutely! This was very clearly just for fun, there's very, very little practical application for this hilarious project.

[@gammaleader96]

Nice, whats next, a giant PCB for your giant DIP sockets? Nice project, the circuit is surprisingly simple to be honest, I would have expected it to be more complicated. EDIT: Another interesting IC to replicate might be an AD633 analog multiplier, that might be quite the challenge.

[@UsagiElectric]

Thank you! You know, a massive PCB with a bunch of huge sockets and tube replicas of ICs would be a perfectly hilarious project! I may just have to do that in the future! Next though, I'm planning on building a replica of the PC817 opto-isolator and then I might try my hand at a 167-pin DIP package and build a replica of the CD4017 decade counter. That AD633 is a very interesting chip! And analog multiplier is an interesting thing to wrap your head around anyways, but the fact they could stuff it all onto a single 8-pin package is impressive!

[@VandalIO]

Would love to see a data sheet for this op amp in Japanese and English with all the awesome graphs and stuff 😂

[@UsagiElectric]

Oooh, a Datasheet in Japanese, that's a new level of difficulty! I am working on a Datasheet (in English) for the 555 timer though! Once Chinese New Year finishes and the PCB manufacturers open back up, I'm going to order V5 of the 555 timer kit and hopefully get a completed version going. Then I can start work on other kits too!

[@VandalIO]

@@UsagiElectric i believe a data sheet for an op amp would be easier than a 555, as we all have access to lots of opamp literature , and I know a smart person like you can achieve anything 😝 , you did create tester for tube which helped you produce graphs in excel , so it can be done hahah , I wish I know Japanese to help you with that , but nevertheless english data sheet should be awesome , can’t wait

[@cheater00]

That's a very cool video. Thanks! I subscribed to your channel. I hope you'll make more such projects. What about a magamp? Is it possible to make one out of a normal transformer?

[@UsagiElectric]

Thank you very much! I have a few more projects in mind that I hope to get to once I get my HP 150A back up and running (which is taking way longer than I was anticipating, but that's not uncommon for old tube gear, haha). I had to look up what a magamp is, but that's a really cool idea! Seems they need a special type of transformer core though, so it may not work well with a normal transformer. They use magnetic saturation of the care, which I believe is not something that normal transformer cores are designed around. But, it does remind me a bit of the idea behind the Parametron, which uses tiny oscillating transformers for logic circuits. I would love to do something with parametrons someday, but that's definitely a "someday" thing! Here's some info on them if you're curious :hardforum.b-cdn.net/data/attachment-files/2018/02/105535_Parametron_Works.png

[@cheater00]

@@UsagiElectric sounds lovely. Personally I'm a big fan of unusual audio circuits, so I'm coming at it from that angle. That's why this 741 video hit so well with me. BTW, is this tube 741 able to amplify something broadband, like music?

[@UsagiElectric]

@@cheater00 I'm right there with you, I really love seeing tubes used in strange ways! The 741 should be able to amplify music, though there are a few things working against it. The biggest is going to be the feedback capacitor. Depending on the value used, it may end up distorting heavily on bass or distorting on mid to highs. A really dynamically diverse piece, like anything Hans Zimmer does, would most likely stretch too far out of the range of the feedback and either result in runaway oscillations, clipping or some other kind of distortion. But, having said that, I now really want to try that out, haha. The output would still have to be fed into an output tube and transformer, because even though the output is buffered through a cathode follower, it's still only able to supply a tiny fraction of the current a speaker is expecting. Once I get the 555 kit version working right, I'll build this one up in a kit version as well and do a follow up video testing it out as an audio amplifier, I think that could be really fun!

[@cheater00]

@@UsagiElectric why is the capacitor so critical? A normal 741 can do full audio bandwidth without distorting either side, so why doesn't this do it? I am surprised. BTW I didn't really understand why you need that cap...

[@Delorean29]

WOOOOOOOOOOOOOOOOOOW!!! I like it 1 of 10 = 10! Can this be ordered? If so, do you want a radio tube holder in the card! What voltage in? If so, what would it all cost? Black pcb 555.

[@UsagiElectric]

Thank you so much! It can't be ordered yet. I am intending to make both the 555 and 741 available as a kit someday, but I've made some pretty massive mistakes on the PCB design, so I'm going through and doing some proper revisions before I place the order for the next version.

[@Delorean29]

@@UsagiElectric Thanks. What does such putty cost with all parts approximately?

[@santherstat]

6502 when

[@garrettvannorden7723]

almost 555 views!

[@UsagiElectric]

Looks like we blew right past 555! Time to shoot for 741 views!

[@garrettvannorden7723]

@@UsagiElectric now its in the run for 2048 views

[@UsagiElectric]

@@garrettvannorden7723 And we flew right past that one too! I have Hackaday to thank for the late surge, they ran an article on the video!

[@deadlyche3014]

time to make a giant wire-wrap computer

[@deadlyche3014]

it would use the ic kits

[@tammasus]

In all honesty. The original PCB matches better with the tubes. More era appropriate

[@clifffiftytwo]

Found this link (spectrum.ieee.org/tech-history/silicon-revolution/chip-hall-of-fame-fairchild-semiconductor-a741-opamp ) on the development of the 741.

[@UsagiElectric]

That was a great read, thank you! I didn't realize there were so many precursors to the 741, but I love that there was a bit of a an OpAmp war going on, haha.