- Wrote an article about the past three years of the MacroFab Engineering Podcast
- Chime Module
- What is the best way to reverse engineer a PCB?
- Ray Alert
- Rebuilt and rewired 3 amplifiers
- Soldano clone went from being somewhat noisy to virtually nothing
- Very interesting grounding scheme
- Lots of dos and donts
- Utracer tube testing
- The Macro Amp
- Nu Tube
- Always remember to over buy parts
- Game idea?
- Zork derivative game that comes on a “com stick”
- Power Supply Design for Clean Jazz Amps
- This is a cool blog about building power supplies
- Vasily Ivanenko
- Lots of images and good analysis
- Heavy focus on component selection and managing grounds
- Bees can do simple arithmetic, offering hop to low-gate-count AI
- Now that is kinda click baity
- Flow Chart on Electrical Component Selection
- This accurately describes part buying for personal projects
- Power Supply Design for Clean Jazz Amps
MacroFab will be at SXSW. We are teaming up with Particle.io to put together a Hardware Happy Hour. It will take place on Friday March 8th from 4PM until 8PM at the super cool Jester King Brewery. Check the show notes for full details and to RSVP. Join us for lite bites and refreshments, network with fellow Hardware nerds and kick off SXSW.
Visit our Public Slack Channel and join the conversation in between episodes!
Special thanks to whixr over at Tymkrs for the intro and outro!
About The Hosts
Parker Dillmann is MacroFab's Co-Founder, and Lead ECE with backgrounds in Embedded System Design, and Digital Signal Processing. He got his start in 2005 by hacking Nintendo consoles into portable gaming units. He also runs the blog, longhornengineer.com, where he posts his personal projects, technical guides, and appnotes about board layout design and components. Parker graduated with a BS in Electrical and Computer Engineering from the University of Texas.
Stephen Kraig began his electronics career by building musical oriented circuits in 2003. Stephen is an avid guitar player and, in his down time, manufactures audio electronics including guitar amplifiers, pedals, and pro audio gear. Stephen graduated with a BS in Electrical Engineering from Texas A&M University.
Host 3 00:11
Hello and welcome to the macro fab engineering podcast. We are your host, Stephen Craig and Parker Dolman. This is episode 159. A quick announcement before we jump into the podcast Mac lab will be at South by Southwest in Austin, Texas. We are teaming up with particle.io to put together a hardware happy hour. It will take place on Friday, March 8 from 4pm until 8pm. At the super cool jester King brewery, check out the show notes for full details to and to RSVP. Join us for food and refreshments and network with fellow hardware nerds and kick off your South by Southwest weekend. So what is today, Steven? Today is the three year anniversary of the Mac vendor engineering podcast. Cheers to that. Cheers. I think on the two year we actually cracked a beer. Like yeah, doors are already open right now though. Three years rock on. Yeah. So next week, we'll be celebrating episode 106.
Host 2 01:14
We'll just do a celebration every week. Yeah, this is great. Three years, three years. Yeah. It's when was it? I can't remember. I think it was like 110 or something like that. Where for some reason, like a couple weeks in a row, I kept just been like, astonished that we were still doing podcasts. And you told me to stop doing that. So we stopped doing that.
Host 1 01:36
Yeah. Yeah, no, it's been a fun ride. And, hey, here's to many, many more,
Host 2 01:44
Many more years. So I did write an article about the last three years of the McWrap engineering podcast. So go check that on the blog. There's gonna be a link in the podcast description to get to there as well. It basically covers like, my favorite podcasts, Stephens favorite podcasts, some cool like guests we've had and some interesting stats like, we have over 300,000 downloads over the entire course of the podcast, which is pretty crazy to think about. But if you add up all the time, downloaded, it's over 25 years of audio
Host 3 02:23
25 years of audio downloaded throughout all 300,000 of those downloads. If you're new to listening to the podcast, go check out that article because it showcases a handful of really good episodes. So if you want to just jump in and find some fun ones. That article is great. Yeah, yeah, they're the ones too. Don't go listen to episode one. Just Just don't. That's actually an interesting statistic I've looked at in our downloads is episode one has doubled the amount of downloads is episode two. Yeah, yeah. So half the people just go like, Nope, this ain't for me. But it's like, oh, yeah, I remember when we released episode one. And like the in the first week, we got 200 lessons. And that was because Parker pushed it really hard and asked all of his friends to listen. And we were like, Okay, well, let's try this again. Let's do another episode. And that had like, 30 or something like, it was like, right. Okay, that goes. So, yeah, go go check out that list. Those are the ones if you're new. If you're new, though. You're already listening now.
Host 2 03:29
Ooh. So you're already one of us. Yes, one of us podcast ception. Okay, with that out of the way, the chime module for the wagon. So I was going to do a schematic of it, but I got sick. And so I didn't end up didn't get around to doing it. But I did kind of like do some preliminary work. And I wrote down all the part numbers for like the ICS that are on it. So it's got a MC 14069 UB which is a
Host 3 04:03
Hex inverter. And then there is a MC 14001 UB, which is a quad Norgate and those are the those are the only two like integrated circuits on the whole board. Correct. Everything else is resistors, capacitors diodes and a couple P NPN. transistors. So what's the interesting thing is it somehow does two different does one tone does that bond noise which is basically your key is in the ignition with your door open right? And then it has the bong, bong bong which is your seatbelts on done. And that's like the passive restraint stuff that they have to do to abide by US law. We are the are the is there like a standard for the Bings and bongs that it has to do? Not really it's in. In the US motor safety laws on that stuff. You have to have passive restraint. rates. That's why airbags in the United States are called SRS. Secondary read straight. I can't remember the last system, secondary restraint system. It's not designed to be the only thing that keeps you alive. Right? Right. Okay, so seatbelt is the first seatbelts the first and the thing is America is weird as Most countries don't require secondary things. Like they expect you you're gonna be wearing your seatbelt. But in America, they are like, well, they could not be wearing their seatbelt. So you have to have something else to help that that's like, in like the early 90s You had those cars that would like automatically built in your dangle belt. Oh, yeah, I drove a car like that for years. Yeah, that's one of those devices that someone some engineer or some bean counter came up with. That was a, a secondary restraint style thing to get around this law. So like, the that's why some cars like in overseas you don't have chimes or anything like that. My, my first girlfriend I had on our very first date, I go and pick her up. And she she gets into my Nissan Sentra, my my 94 Nissan Sentra, the very first thing she she does is she sits down, she doesn't realize that it's an automatic seatbelt car, and it grabs her hair and just just like yanks, like a ton of her hair. She had long blonde hair, and it just sucked all of it up into the car. And I had to spend like 15 minutes like slowly pulling her hair out. No, no, out of the door. Yeah, good first date. You had to get dessert that night, right? I don't know. I don't even remember what we did. That's best. The one thing I remember from that. So I'm thinking it's using the hex inverter, probably to do the oscillations to make the tone right? Oh, for sure. Yeah, yeah. Because with the hex inverter, you can make a you can make a an oscillator, if you just feed back the the output of a hex into the input of a hex and do an RC filter. And just depending on the RC filter, you can control the frequency of the oscillation, which is probably how they have two different chime tones, right?
Host 1 07:20
Well, there's, there's only one tone, but it's continuous or intermittent.
Host 3 07:26
Oh, okay. So, okay, so they probably so it sends to hex inverter they have they have a handful of these things inside the chip. One is producing the tone and I bet you one another one is set to produce the on off off on Yeah, yeah, that the timing for that. Yeah. And I'm going to bet the quad NOR gate is set up to do the logic of like, door jamb open key in seatbelt undone. What do I do kind of thing? I'd like to see a Karnaugh map for that, you know, actually, I don't even know how that actually functions. Like if you have all of them, like undone, like, what does it do? I don't know yet. And so there's got a couple of like, you know, NPN transistors, like I bet sure some of them drive the giant piezo like the metal can piezo on it. And then one is set up to drive the it's almost like a direct drive output to the seatbelt indicator lights on the dash. Which is that red, you know, person the picture the red person? Yes, we all know that. We all know that symbol. Yeah. It's funny how like, almost everyone, every car manufacturer uses that symbol. I think those are standardized. Honestly. I don't know if that stands. Yeah, no, I'm pretty. I'm pretty sure that and the low tire one. Which if you've haven't ever seen the low tire one before you look at it, like, what is this trying to tell me? You know? Well, yeah, it's like a triangle with an exclamation mark. And it's like, what does? What? Oh, no, the low tire one looks like looks like some weird, like circular calipers or something like,
Host 2 09:04
Oh, yeah. On some cars. Yeah. I think on Toyota is like that. Yeah, maybe it's like if you looked up like seatbelt indicator light, like that was the free one that you can download online.
Host 3 09:18
Everyone uses Sure. They're not gonna, they're not gonna spend the time to draw that. They're gonna design a car, but that's where they're gonna cut corners. So on that chime module, I bet you the way that they produce like the on off signal, I bet you that they're not getting fancy with it, it's probably they're putting their signal to the piezo or through an amplifier of some sort, probably just a transistor amplifier. And I bet you they have another transistor, that when they when they put its base high, because it's all NPN it probably just shunts the signal to ground. That's how they get the on off on off. It's probably exactly that. Because that's like, that's the cheapest possible way to do that. Yep. And so my My question to our listeners, is it so it's a single sided board? What would be the best way? Or facet? I'm going to say the best way, what's the fastest way to reverse engineer PCB? To go from this PCB to a schematic? So you're you want to your end result is a schematic not a copy of the PCB, right? Right. I just want a schematic so that we can look at it and say, Okay, this is how this thing functions. I don't know, let me call up China real quick and ask how they do it. So I had the idea of, so I did the, the air, the air conditioner, control module, that was a really simple circuit. And so I was able to like just like, use a multimeter and continuing the mode. And that only took like 30 minutes to do. But I started doing this. And this is way more complicated. It's got like, four times the parts on it. It takes a while. Yeah, it takes a while. And I'm like, man, there's got to be better way to do this. So I've been thinking about, you know, take a picture of the board, and then draw on the traces or like, do contrast manipulation to bring the traces out, and then put that image into like, Eagle, because I can import a image into Eagle as an overlay, and then put all the parts down, like where they would physically be, and then just connect them with nets. Yeah, so So you're drawing the schematic on the PCB? Yes. Yeah. Should work. Yeah, that could write. Every time I've ever done a reverse engineer on a PCB. It's just, I've got I've got a piece of paper, I look at the board, I follow a trace, see what it hits. Draw that follow a trace, see what it hits draw that, like, I don't know of any better way other than, like, using an x ray machine? Yeah, that's what that was the method I was using. I'm like, Man, this is just taking too long. I don't have time for this. Well, I mean, the way what we described, I can't think of any other way they would do things. Yeah. Because I mean, like, obviously, that thing was built to a price point, like, oh, yeah, going as cheap as possible. So yeah, I, I'm less curious about the oscillator. Because if you see x inverter in something that makes a noise, you automatically know it's okay. They're just using that as an oscillator. But the NOR gate stuff would be interesting to see. What is their logic on? Yeah. Although one thing though, they very much guaranteed our filtering that hex inverter, because if you put a raw hex inverter wave into a piezo, that would be one of the most awful sounds you could possibly, I mean, it is pretty awful. If you recall, it's I mean, it's not great. But but they're not just putting a just a nasty square wave into it. It's got a little round edge on it. I think there's there's a capacitor somewhere that's just taking the edge off and taking all those harmonics out, right. Yeah, yeah, yeah. Because hex inverters are pretty good at making sharp edges. Yes, that's their job. Alright, so hopefully, by the next podcast, I have this done. And then we can actually dive into it. And maybe I'll bring up the other module we need to repair the compass and temperature module that's in the overhead console on the wagon. Well, you're going up in difficulty in terms of reverse engineering. Yes. That's great. How many? How many modules? First of all, are on that car and how many are broken?
Host 1 13:38
Oh, okay. So so there's the ignition control module, which it controls the
Host 3 13:47
The, the, basically the spark that goes to the distributor that is functioning and not using it anymore. I've upgraded to a GM style Hei, which is high energy ignition, so uses more voltage basically. So that works, but it's not in the car anymore. There is the air conditioner control module, which didn't work but now works because we fix it with a new transistor and capacitors. There is the intermittent right wiper for the windshield wipers. That works fine. There is the cruise control module, which does not it works. I would not trust it though because it like you'll be cruising along and then we'll decide the change speed. Like all of a sudden change speed. Yeah, all of a sudden wants to like accelerate or slow down and you're like, yes, I want I actually ripped out all the all that stuff does. That's a sign of in the wagon anymore. Okay, that doesn't work. That's four modules. There's the overhead console module. Which does like temperature in the Office that kind of works. It doesn't display anything like you can some sometimes the display will come on and it'll be like just like the seven segment display of gold funky. So I think that one just needs to be re soldered and new capacitors. So that's five and then there's a, there was an option to have actually a remote like a key of remote key to unlock unlocked doors. The it's interesting that the basically the overhead consoles have that circuitry in it, but the rest of my car does not. So technically at six. I think that's all it's in there. I can't think of anything else on top and a good chunk of them. Were not working, correct. Yeah, half of them are not working. Okay. That's a pretty good chunk. four out of six are not working. So my last thing is I was going through my late uncle's like boxes of crap that have just sitting over here. Like a lot of them will old vinyl records and, and stuff like that. And I found this. It is a ray alert. Tester. Okay, copyright 1968 Printed in USA. And it is to measure TV X rays emitted by black and white and color sets. Oh, that is great for 395 Still in packaging. Yeah, it's still blister packed cheese. How old is that? It says Raelert, the new television X ray detection system. So my question is, you might know this even if not, then it'd be to our listeners is was this a legit thing back then that you had to measure x rays coming off your TV? Or you would fry your kids brains? Because they were watching Saturday nights or Saturday morning cartoons too close to TV? And does that word the phrase like don't sit too close to TV or your eyeballs will melt? Yeah, actually, from what I know. Yes, that is what it what that phrase is from? And so yes, the short answer is yes, those tubes technically are capable of emitting X rays. Now I think it's, I think as soon as you say X rays, people go, Well, maybe not as much nowadays, but But it used to be that people would just freak out. Even if there was a singular particle X ray, people would freak out. So those tubes are capable of emitting, they are coated on the inside, you know, if you've ever pulled out one of those tubes, they have, they have the phosphor coating on them, but they have that big thick like grayish paint on them. That is to contain X rays. They're not supposed to emit X rays. A lot of times with those kinds of tubes, the way that you can emit X rays is before the tube is is warmed up or it's been heated up the end, you apply a huge voltage to it, you actually can strip electrons off of the cathode before it's hot. And it's before there's a cloud of electrons in the vacuum of the tube, you're you're yet strong enough the electrical field is strong enough to actually rip electrons off. And that results in a x ray effect. There's a great YouTube video of a guy taking a fairly standard audio tube and he doesn't heat it up at all. And he just puts something like 3000 volts on the plates and puts a Geiger counter next to it and it's going nuts so yeah, you know, you know you know for most like applications where you'd have a tube which nowadays is like audio amplifiers
Host 1 18:45
If they're not at a voltage high enough to actually MIT X rays, but TVs and old CRT monitors are in the two to 3000 range on the on the glass itself basically. So it technically it is possible. Gotcha.
Host 3 19:04
I haven't opened it up yet. I wonder if I should open it up eventually to read like the instructions because as please read carefully, but on the back it says note please allow approximately two weeks for the return of your ray alert TV X ray rating report so I guess you expose the film I guess that's what's in here to your TV and then get the ship it off. So for two weeks your TV can still be bombarding you with X rays that's pretty great. You know that oh, maybe little Timmy shouldn't be sitting two feet from the TV now. And he's got like a third eye stock growing out his forehead now. Well, I think Okay, so let's let's all be honest. They the kids set close to the TV because the TV was like eight inches wide which is which is funny. I actually I actually just bought a TV the other day And it's supposed to arrive. Tomorrow I think, a 55 inch. A, I can't remember what technology it is a 55 inch TV cost between three and $400. Nowadays like That's insane. That it's that cheap now to to make something like that. Well yeah, just how much you I always think about is like the material how much material is there? You know? That's why I always think like It's like gasoline. It's in the United States is fairly inexpensive compared to the rest of the world but like, there's so much energy in a gallon of gasoline. It's like, right now in Texas, it's like $1.84 gallons cheap. And everyone's be like, Ah, whatever. It's me. I'm like, Isn't that like California prices at four bucks a gallon? That's still very inexpensive for what? How much energy is in a gallon of gasoline? That yeah, that's how I always view it is like materials and energy consumption. Like milk. Milk is horrendously energy inefficient to make to like, take care of that cow and stuff. Yet, it's $2 a gallon. Well, yeah, it's that because gasoline has so much energy. What milk? Yeah. And milk is at jazz cheap because of gas. Possibly. Yeah. So you know what's cool about this TV I just bought, but I've been to the factory where this TV was built. And I know the guys who built it. That's, that's cool. Yeah. It was built in Tijuana. It was built in Tijuana. Yeah. So that's cool. I you know, it's probably not though I probably didn't see this one being built, because those guys were building 4000 TVs a day. But, but I know that I know the line that it went on, which is really cool. It's like, when you say 4000 TVs a day, it's like, man, we buy that many TVs? Okay, no, no, let me put this into perspective. It's not that we just buy that many TVs. This one factory was producing 4000 TVs a day, purely for the Christmas season. Not for just like regular consumption. Only for the Christmas season. And they were doing 4000 TVs a day for six months. Like that's ridiculous. That's insane. It always reminds me of what's another like high volume and I just had I had a high volume thing that you wouldn't think that we mattresses you like so here in Houston is like Houston's famous for how many mattress stores we have. It's like it's like a mean, we got mattress Mac out there. We got a guy who on TV who cuts mattresses with a chainsaw? Yes. But it's like, on almost every other corner here in Houston. There is a mattress store and it's like, who? Who buys that many mattresses. There's a lot of people in Houston. Yeah, no, but it's like it's just one of those things like me and you. Like we don't buy mattresses all the time. Like when's the last time you bought a mattress? Oh, you just moved so it could have been recently? Well, I got a new mattress but my inlaws wanted to come and stay with us. So they actually bought a mattress for them to sleep on. It so it's like the it's like I bought a mattress five years ago, but it's like how so if you buy a mattress like once every it's supposed to be like once every eight years according to the advertisements, right? Because of course they want you to buy more mattresses. Big mattress is coming for you. Mattress Mac is going for you know mattress Mac is cool. He's got his he's the patron saint of mattresses here in Houston. Yeah,
Host 3 23:59
He's a legit guy. Yeah. So it's like, it's well, it's like one of those items that you don't buy a lot of. But yet as a society, we consume so many of them. It's like cars, like most people, you know, buy a car every five years or whatever. Sure mean you only buy jeeps and you but you'd like drive out in the middle of nowhere and there's like a dealership that's got like 8000 cars on it. It's like who is buying these cars? Then somehow they all go and they all sell. It's amazing how you I guess you just don't think of like, like the grand scale of the population that way. Yeah, especially like, ya know, you even go out you go out to the boonies and you see, like a place that has like 400 trucks, and each one of those trucks are like the supreme like 60,000 and dollar model Yes. Crazy. Well, that's but that's also you know what? That's coming from a Texas perspective where everyone drives a $60,000 Yes. As like a commute truck, you know? Yes. I don't know how to drive this 10 miles a day. Yeah. To work. And it were dually and I live in the suburbs. Yes. And in 90% time, I'm stuck in traffic. Right, right. Exactly. Yeah. So Steven, where you been up to? This is now the the mattress engineering podcast. interesting topics were third year anniversary. Yeah. Look back at this one. So, you know, I kind of started ratcheting things up here. Now I finally have a basement. And I finally have like an actual workspace. And I've been like, equipping myself to be able to actually work. I have a bench now. And I just started going nuts. So I see one of those amps back there. Oh, yeah. There's actually just out of frame that that Parker can't see right now. There's just like, a whole, like, slew of amps over here. So like, all like, it's funny, because when I moved, I got rid of most of my functioning electronics. And I kept all the broken. Yeah, I remember I had to move all those amps. Oh, yeah. That was Oh, yeah. I don't know how that u haul made it up those mountains. When when when I was climbing the mountains, when you first come into Colorado from Texas. I had a pedal to the metal and I was barely maintaining 40 miles an hour. So yeah, because it was many hundreds of pounds of amps. Stephens wife is a school teacher. And so all of her stuff was just books. Oh, those were the there were small boxes, like moving boxes. I swear there was led in them. It was just books though. And then Siemens as all chassis tube amplifiers and transformers. And we filled up like, sort of God, like the largest U haul I've ever seen with just that stuff. Here's here's the funny thing. Just not even, like probably a week ago, my wife Lauren finally admitted that we technically have about the same amount of stuff. The thing that that's funny about is the volume of stuff that I have takes up like 1000 square feet. And the volume of stuff that she has takes up like 200 square feet, but by weight they're about equal. So what So who wins that argument? Isn't a volume or weight? Oh, no, we're just going with equality on this one. I got a go. Yeah, that's the best way to go. Yeah, that's the whole point on this. Yeah. Yep. Yeah, that's so so yeah, I've really gotten back into working on apps, which feels super awesome. And, and honestly, like, in the past summer, and everything, a lot of the projects I was working on, like the U traits, or tube tester and stuff was all kind of like, in preparation for the fact that I know I'm finally going to get a bench back. And last weekend, I ran for new circuits in my basement to get power everywhere and stuff. So gosh, in the last week, I repaired a tube amp from my from my buddy, and I rewired three of my amps, like pretty much from the ground up, which was just a ton of time, but it was not super awesome. It's a lot of fun. Now, one of the things that's, that's great is I sort of made a like a rule for myself a while ago, where it's like the first amp I ever built. I was 17. I was in high school. And I just I didn't know what I was doing. I built it and it actually worked. And I was like, Oh my gosh, this is awesome. And I made this rule is like I'm never going to touch this thing. It's going to be like a relic. And then I put it on my bench. I was like nope. And I gutted the whole thing.
Host 3 28:59
That's the old bronze and green one, right? Yeah, the that one and just completely gutted it and rebuilt it from the ground up. And it sounds awesome now and I like good buddy of mine has had it for a week now. And He's drooling all over it. But the whole point of bringing that up is that it's always fun to look at electronics that you did in the past. Because it's one of those things where I crack it open and like, Oh, I did that. Like I made those decisions. I've done that with electronics like the like layouts. Yeah. Open up old, old, you know, Eagle files and be like, ooh, yikes. What was I thinking doing that? Yeah, yeah, exactly. And a bunch of though in a couple years, I want to look at the boards I'm doing now and be like, ah, that's bad. Oh, for sure. For sure. Yeah. And, and even rewiring this amp now like if I have it in another 10 years I'll look at and be like, Oh, what did i Why did I do that? Because you're always learning new techniques. Yeah, better ways of doing stuff. Right? Well, and that kind of leads into one of the thing that I was kind of messing with. One of the other amps. I've rewired is a is a clone of a Soldano amp, which is a brand out there. And they had a, they've had a classic amplifier that was designed in 1985. And it's still in production now called the SLO 100. Think that stands for Super lead overdrive, 100. And it's 100 watt amp Go figure. It's a cool name for an amplifier though. Yeah, everyone just calls it the slow. And so I built that that's actually the second app I ever built after I built that green and gold one. And it's always worked. It's a great app, but it always had issues. It was noisy, and a handful of other things, you know, that I've had to maintain over the years. But I've rewired it and did a lot better wiring practices and stuff. In fact, my goal is to put it in a completely different chassis eventually, which I have that an order and it's on its way, but I just wanted to get it back up and running. And one of the things that was interesting is, with rewiring it, knowing what I know, now, I redid the grounds and I redid a lot of things and paid a lot more attention to you know, where my currents are flowing and high currents versus, you know, high gain signals and things like that. And upon turning this on, you know, after doing all the wiring, it's actually surprisingly dead silent, dead silent, meaning it doesn't have hum or Buzz, it has a ton of hiss in it. It's actually pretty loud with the hiss, but zero hum and buzz, which that's actually kind of difficult to achieve. And it's really interesting, because with old tube amps and things that even though they all play by exactly the same rules as every other electronic device out there, like you just have to do things differently. It like everything still applies, all the physics are still there. But you just have to do everything differently. That's why they're still wired the way they are. And I don't know, it's interesting, but but all the hiss that's in that amp is due to the fact of that. There's a lot of old resistors that have taken a beating, and they've just grown to be noisy in here. See, so I actually need to replace most of the resistors in the signal path. So is it like? Is that just like hitting the resistors? Hard with signals? And like transient spikes? Basically? Yeah, causing, like the carbon or whatever the filament is the grade? Yeah, that's
Host 3 32:43
Right. I use metal film for most of the resistors on that, because middle film is generally low noise. And, uh, but but some of them is due to just being hot and running lots of current through it. And just, you know, beating it up, that can cause a registered agent be noisy, and this amp is to oh, gosh, how old is it over a decade now. So it's, you know, and it's seen a lot of abuse. So it's not surprising that it needs a little love on that. Also, it's interesting. What, you know, something that would be really fun one day is to kind of like dive into noise, not necessarily in amplifiers, but noise in electronics as a whole. Because if you've ever done like gain calculations across stages, like analog stages, and determining what components are really sensitive, and what components are not sensitive, as in, like, which components should you put your your energy and focus on when designing it? That's a really interesting topic to dig into. And it's really interesting on tube amps, there is one resistor that dominates the noise in the entire amp noise in terms of hiss. And that's the very first resistor that goes into the amp because that just there's so much gain after it. That's your loading resistor, right? That's the resistor that keeps out. radio noise. Yes, yeah. Yeah. I remember you were talking about that one. Right. So So you know, I bet you if I just replaced that one resistor with a new one, I'd probably get rid of half the noise on this thing so but I've also when you live far you live farther away from Texas now to so you can lower that resistance. I'd still pick up at Town station Gary would no matter what some yet. Heard it on the X. Yeah, that's right. So I did I have actually busted out my old day. You tracer, not old. I just did that a few years. That was like the last project he did. Yeah, yeah. I've been using that extensively, actually, in the last couple of weeks because I have all my boxes of tubes and stuff out now. So I've been cataloging all my tubes and testing them. And it's it's so much nicer than it used to be with with the old tester and it works works for Great. But in in doing all of that, I have 10, eel 34 tubes that I've been testing. And there's a particular reason why I've been going through all these eel 34 tubes, because I resurrected, the macro amp. And for those who've been listening for a while, those who've been listening for a long while, will know that I've had a it's not the oldest project. But it's like, the third or second oldest, that's not finished. What they know every project is not the oldest project. There's only one, like, just across the board that is the oldest, you know. So yeah. So the macro amp here was was a tube amp that I designed a long time ago. Gosh, we were in the old building at mag warehouse. Yeah. And it's funny because I have all the parts, I've got everything to build, I got the enclosure, I got the boards made and everything. It just never got, like put together and wired up. But I have, but it runs on to l 34. tubes in the power amp. But it uses some of the core new tubes, which are the vacuum tubes that are put inside of the VFD. Kind of like Shell. Yeah. Which I've been using that as a headphone amplifier at work. So listen to music, too. And, and I was like you know what, it's time to kind of like pull that back out and put it back on the the healing bench. Well, I built some shelves as I'm actually trying to get a little bit organized here. I built some shelves in my in my basement and put every major project on the shelf, such that on the shelf is right at the stairs when I walk into my basement. There's every time I walk into my basement, I have to see everything I haven't done yet. Oh, it's good motivator. I think that's torture. I've actually I have a I have a Trello board now that I've made for my shelf here. And each item on that shelf has a Trello board or its own like card with like, what is the next thing I need to do on this. So I'm trying to knock those away. And that's why I like doing a bunch of amplifiers. It's like those are low hanging fruit. Those are things that I could do in an afternoon or over a weekend. And you know, kind of get it back up and running.
Host 3 37:19
So I was going to give an update on the venti que my 20 band EQ device, but I made that's not on the shelf now. Right? Ah, gosh, I don't even know where that one is right now. It's on the shelf. No, I'm joking. It's on the shelf. It's in a box on the shelf. So one of the things. The last I left it was it's working. But it needs it needs a little bit of love, you know, some just tweaks here and there. And so what I was building, in fact, give me a second. I've got it right here building a tester. Yep. I built a little tester on some perf board here. I made a rookie mistake, though. And it's funny because it's not it was like, I made a skilled rookie mistake. And and here No, here's the here's, here's the reason why. So always remember to over buy parts, if you're gonna, if you're gonna buy parts, and they're cheap, just over by and throw them in a bin somewhere. Like on my floor over here, I have bins of like excess parts. And I use them all the time. Like it's totally worth buying over. And here's the reason why. So I was building this little testbed. And the whole point of this testbed was just to be like little pigtail wires that I could test my all the bands on my Yeah. And so I had the, I bought one connector to connect my bands into one of those PCI connectors. And I started wiring to it. And then I was like, Oh, I could add this. And so I started wiring to that. And then I said, Oh, I could add this and I started to add in wires. And before too long, like I ended up melting the connector from like doing a little bit too much extra work on it. And I was like, I don't have an extra connector and now it can't work. So I had to shelve this at buy an extra connector, which it arrived the other day. But now it's just like, why didn't I buy two of them, they're like 40 cents. But because of that I had to I had to you know, shelve it for a couple extra days and not put any work into it. And also, in the meantime, I also figured out a much better way of doing this. So what I mean by made a skilled rookie mistake, I made the rookie mistake of not buying extra, the skill part was like I was adding useful things over and over and ended up just that was not a good way of doing it. And those those connectors are not necessarily intended to have pigtail wires connected to them. So I'm just going to sacrifice one of the extra PCBs I bought that has the footprint on it. And I'm going to wire to the PCB, which is much better so So, so yeah, that's, that's my section. Cool. So we were talking about this before the podcast, and Steven revive always wanted to make a video game. And so we had this like grand vision of like a point click adventure space game. Like the old LucasArts Yes, you know, point and clicks those are so great. Yeah. And the problem with that is we either have to bring in more talents, right? Because I'm we're not animators we can't do drawings or anything. Like we can code and make music. That's like a third of the game. So, and so we decided, hey, what if we made a text based adventure game, like Zork. And so we can, let's just read Zork for a second, just just because we might have some younger kids. Zork was an old gosh, I think it was an MIT grad students created Zork. And it was a all text adventure game. So basically, it was just like, playing a game in command prompt, where you just type in everything you want to do kind of like Dungeons and Dragons, but you play by yourself and with your computer. So it's like extra sad. But But no, it was one of those games games where like, it would say like you're standing in a field, there's a house to eat. Yeah, I would explain describe it and be like, What do you want to do? Walk north, and you would walk north and you would describe the area around you again, you find flask pickup flask, you pick up flask. And if you went into dark areas, that was where the girls lives. And the grooves Yeah, you've been eaten by a grill, if you've ever heard that, that's what that gauge that's from sorc. And so my idea was like, Hey, let's take our space game idea and make it a tech space. adventure game. So we can actually like, build the story story in quotes, the world, the map, because then we can take that later and apply graphics to it. Because a point and click game is basically Zork with graphics.
Host 3 42:13
Yeah, yeah, exactly. It's actually it's actually a lot faster, because you don't have to watch the graphics. Like as soon as you hit Enter, everything takes place, right? Yes. Yeah. And so and I was thinking, like, what would be really cool, is, I mean, we would probably give it out for free, like something that you can download, but put it on a thumb drive, like a microcontroller. And that you plugged into your computer, and then you can import it into it. And that was the world was on that thumb drive. And I think that'd be really cool concept. Because that way we do a little bit of hardware design, but not much. And I think if we did like a sci fi space, like tronics, kind of like a, what would you call it? There's a game. I'd have to I'd have to have the word cyber at it somewhere. Yes. Like, well, there's that game cyberpunk. 2077 coming out. Yeah, like a cyber free kind of game. Because then it makes sense to have that thumb drive. Like, that's the you going into the world kind of way. Yeah. Yeah. Yeah. Okay. So a quick thing that we could add to it that would be really easy, is to put a little buzzer on it and PWM it. So, like, the music for the game comes from the stick. So it's like an old 386 computer where it just had a buzzer in it. You know, I like I liked this idea. Yeah, yeah. I like this idea. I think we can totally pull that off. You know, actually, you know, what we're doing is we're basically making a DEF CON badge. Basically just a badge. That's a little thumb drive, right? Yeah, yeah. Cool. Yeah. So I think I'm going to go up to Stephens place up in around April time. And I think we're going to hash out the entire map and world and how everything interconnects all the items, and then we'll just start applying go to it. And see what we get with it make an entire game that is firmware, like no software. I mean, that's what Zork is. Exactly. But no like this this game is just like a USB plug and play. Yes. Cool. I think a lot of fun. Good. Yeah. Yeah, I like the idea and frankly, the hardware side of it is like okay, just whatever controller that'll just talk serial over USB. We make sure we have enough RAM and ROM and, and then I open the do the buzzer. And yeah, that's That's it? Oh, I think you would have to have an RGB LED as well, because then you can have the color of what room you're in. You know, okay. That's really funny because I was literally just about to say, Okay, I was thinking having three individual LEDs, and like maybe there's a part where you're like you have Under like Hacker Safe or something like that, and you have to like look at the code, and like read it or something like that. Oh, I like that I had to I think there's a lot of cool ideas we can play with, like secrets you could put in there. Yeah, yeah, I think there's something we can do with that, where it makes that dongle because that's what we're doing. We're building a Dongle for it is is part of the game. Yeah. Oh, man. That's kind of cool. Like to advance in the game if somehow you have to hack hardware. That's kind of cool. That's actually cool. I did too. I like that. Yeah, these are all good, bad ideas. We're giving them away for free. We'll do it in April. Yeah, yeah. We'll just we'll just go out to a bar and just sit there for a while and come up with a weird game. I cool. And it has to be cyber something. Yeah. All right, let's, let's roll on over to the RF Oh, the rapid fire opinions. So the first one on here actually found on Hackaday. And it kind of goes along with what I was talking about. With all the amp stuff. There's a really great article that was featured on Hackaday. It's about a power supply design for clean jazz amps. And really, it's more about just power supply design. Just the application that this was being used in is a clean jazz amp. And the the guy who wrote the the blog post, talking about the actual power supply, his name is Wassily Ivan Nemco. I'm not great at pronouncing Ivan enco, we'll go with this guy is straight to my heart, because I went to his blog. And the first thing he says is work safety safely prevent accidents and fires. And he has like, the first thing you need is fire extinguishers to do this project. And I'm like I liked this guy. Well, I think he's talking about that, because he's legitimately plugging into mains. And what's really kind of cool about it is if you if you look at just like even the the top picture of what he's doing, he's got a Manhattan style power supply that he built out of PCBs that has mains power going into it, which is like oh, yeah, look at that. That's that's that's like a guy after my heart where it's like, oh, yeah, that's awesome. Oh, he's
Host 3 47:12
Made a major, you old and soldered the shield together? That's right. Yeah, no, it's this guy. So so this. So even if you're not into like, amps, or whatever, go read this article. It's a great analysis of power supplies. And he goes pretty in depth with, excuse me, controlling way your currents flow and grounding schemes, and all the you know ins and outs of how to properly connect everything together. Because a power supplies. A lot of times we think of it as like a power switch ground and a wire that delivers juice. And that's, that's it's a lot more than that. And, and yet, you'll get in trouble if you if you apply that mentality to every circuit your work on. So go check out this this blog post. It's pretty great. I think it's the first of three that he's coming out with. And so it's pretty extensive for the first one. Yeah, great read. Yep, I like this a lot. So go check it out. And I just like his construction techniques, and his construction techniques are the kind where it's not super professional, but it's very, like, I guess the right word is like, sort of academic as in he's like, I'm building this to prove a point as opposed to building this to make it look nice. Which is his, his, they're kind of like schematics. But they're more like system schematics. Like an overall thing. I've really liked how he's drawn those as well. Yeah, yeah. He put a lot of effort into it. And anytime someone does Manhattan style, I'm doubling up on that even though I've technically never built a Manhattan style myself. Um, I don't know if I'm that crazy. Alright, so the next article is BS can do simple arithmetic, hoping or offering hope to low gate count AI. So that's the title. I think we, we basically we were searching for our LFOs earlier and I found that and it was just like, I didn't even read the article. At first. I just sent it to Parker and I was like this. This is good. Apparently they used shapes that are different colors to figure out if bees can do math, and apparently they have some way of doing arithmetic.
Host 1 49:41
Yeah, it's it's a really, it's a really stripped down way of proving that. And basically what they did was they had multiple tests that the bees could do. And they got statistical analysis on how many times bees got it right and you wrong. And the in terms of the arithmetic bees were getting it right more often than they were getting it wrong. So they said bees can do arithmetic.
Host 3 50:09
Yeah. And it's something like at best 72%. Yeah. And so the whole idea is with this is maybe going forward, we can use simpler machines than we think we have to do AI. Which makes sense, because these brains are a lot simpler than human brains. But also, it's like, if a car was only going to be like, a self driving car was only correct 72% of time, there'd be a lot of dead people. So I don't I don't I'm not quite by that jump. But okay, let's let researchers have their fun with their BS. That's kind of a click Beatty article for engineers, you know, a little bit. Yeah, just a little bit. Yeah. Okay, and the last RFO for this week is a flowchart on electrical component selection. And this I looked at and I'm like, Oh, my God, this is like me in a nutshell. So So you start at the very beginning, it is how much do I like data sheets? That's a great place to start. That's the first start. If you like data sheets a lot. You go to digikey Mouser. If you don't you go to add a fruit, Spark fun and polu and get like a breakout board that has Arduino code, right? When you go through that thing, the best thing is characteristic curves. saturate my emitter is if you'd like data sheets. That was great. That's so it goes discrete. Yes, apply filters. And then you look at the results. And it always goes to zero remaining surely exists somewhere. Yeah, like that's, that's the end result. And then there's, this has gone off you with like always buying extra parts. I don't need 100 amp 100 volt MOSFET now, but I'm sure it'll come in handy sometime. Order update 25 high power and MOSFETs added to your cart. I didn't follow the flowchart. Yeah. That's the beginning of that where it breaks off and you either go DigiKey or Mazzer or add a fruit and spark fun. That's perfect. That's so great. So H e k 0707. of Reddit. That is hilarious. Yeah, super. You get all the upvotes that isn't discreet. No, apply obscure, unhelpful and irrelevant filters. That is totally what it is. This guy's been been trolling or lurking on Mauser for a long time.
Host 1 52:41
Yeah. Kind of as a follow up a few weeks ago, we talked about Mauser changing their website. Have you used it much?
Host 3 52:50
Yes. And the filters are fine. It's you still got scroll over for that filter box. Yeah, so annoying. Yep. Yep. Yep. I've been using it a bit. I mean, it's fine. But I just wanted to get your thoughts. Yeah, it's like just make it so that all the filters fit on one page or make it so that it goes double room. Right. Right. Yeah. And allow me to use my middle mouse wheel anywhere on the page. Not in like a little defined area of cool. So that was the third anniversary of the macro engineering podcast. Thank you to everyone who listens. Yes, thank you everyone. And to another year and more years after that. We are your hosts Parker Dolan and Steven Craig later everyone take it easy thank you yes, you our listener for downloading our show if you have a cool idea project topic. Let Stephen and I know Tweet us at macro at Longhorn engineer or at analog E and G or email us at podcast at macro hub.com. Also check out our Slack channel. Our Slack channel isn't three years old yet but we have over 320 some odd people in that channel. It's making goofy faces that me in the chat. If you're not subscribed to that podcast yet, click that subscribe button. That way you get the latest episode right when it releases and please review us wherever you listen as it helps the show stay visible and helps new listeners find us
Transcribed by https://otter.ai