 Hello everybody and welcome back to my channel now. Let me just give you a quick look at the set up here What we are going on so This they're the furthest First circuit here what we got is This circuit here is the first one that I made And this is the latest one that I've made it's the same circuit The difference being is I've used Like BD139s and BD140s over here, and I've used more expensive chips I can't remember what they are, but they're I'll just put them up on the screen I've used this on I've used all of that on this board Even the more expensive output transistors and again using the mediocre output transistors on this board There is a slight difference with all the caps these hundred micro farad Are the same but the hundred nanofarad caps over here. I've used these poly film No reasonably you know cheap enough. I think they're metalized as well I can't remember if that's self-healing but down here. I've used the Weemer poly caps and There is a little bit of differences with this now. It could just be down to the layout Sorry my hands shaking about there It could be just down to the layout. I'm not sure but on the outputs. We've got a one-scope here We've got one scope on here, and we've also got a hundred watt eight-ohm dummy loads now the The bias settings on these around about 50 millivolts each Well, I'm getting off the collect as I should say I'm getting 50 millivolts So which means it converts to 75 milliamps Give or take you know a couple of milliamps either way and this is You know it can be dependent on the and the temperature in the room, but I've checked them again today. It's been warmed up and And Yeah, so what we're gonna do is we're just gonna look at the software and see what that tells us about the outputs of both of these amplifiers The first one I built comes with this power supply. They're using exactly the same transformers they connected in to the Main's had exactly the same voltage So what's coming out these transformers should be pretty much exactly the same the difference is on here. I've got them a Discrete bridge rectifier here Like what a chunky one come of these are six kind of these are six or 10 amp and Over here. We've got a 35 amp bridge rectifier and we've also got an X2 Capacitor to you know keep the noise down the line level noise and underneath here I can't show you because it's set up and it's on is that there is also the X2 capacitor underneath there different Brands one of these came out of an old power supply, which is underneath here and this one so V shape Not cheap and that's on there You've got different. It's pretty much the same amount of millifarads Capacitance, but this is broken down into three hundred and thirty 3300 micro farads per capacitor where this is 10 millifarads or 10,000 micro farads, and this is 4.7 millifarads or 4700 micro farads So there are little tiny differences like that So what I'm going to do now is we're going to just go over to the screen here and We're gonna See what's going on now on the first one. I've set them both to both It's actually down here is 40 watts at the moment And this is THD and noise versus the frequency So I'm just going to get it running and what we will see Coming out of this is we're going to go straight up to 40 watts Which is quite a big jump anyway, and you'll see down here on the spectrum analyzer so the blue is Channel 2 and channel 2 is the new Board and the red is channel 1 channel 1 is the older board And here you get to see as it's going through the different frequencies What's happening in the background here and the differences and this is just a sinusoidal As you can as you can see there and if we look across here, we can see that everything's staying so around about a minus 75 db Or just under which is quite nice and we can see here that we got naught point one percent distortion naught point That's a zero point zero one percent and zero point one percent And that's going across the board At 40 watts into eight ohms We can look all the way down this but just keep this video sort of shortish I'm just going to go through this and you can look at this yourselves I'm just going to go for those points of interest which would be these peaks And then you can see down on here as well how that relationship is between here and the FFT on the spectrum analyzer So that's pretty good you can see those numbers there I mean I'm looking at the top right now to the zero point zero five five five five five five five five yep of the old Let me just check that again. Yeah of the older version and The the newer version is this blue line here So both things that are the same and then we got this little crossover point like Where the bluer version doesn't quite do as well as the older version I'm not quite sure what there are why that is But we can do that again on just THD run that again again at 40 watts because that's Pretty good. Sorry if you can hear a noisy noise now in the background. That's my boiler. It's kicked in Happens to live here in the same room as me I don't know if they did that. I really don't know Again, you can see that the older version in the red is Just very slightly but when we're talking zero point zero three and zero point zero four On the percentages here. I'm on distortion When it seems quite nice across the across a frequency we're going between 20 hertz and 2000 hertz The nice thing about it is they do stick well below the 1% that is that is quite nice there So let's skip over now. Now things are warmed up a bit. We're going to do a We'll do a look at well, let's do a frequency response look first So both channels again, we're going from range of 10 to 5000 hertz at 50,000 hertz And I'm gonna put the the level up to Let's see well, if I can probably about a 800 millivolts is probably, you know, that's one of the highest levels you can put into this So if I put it about six or we can do six five I think we can do that. No, we just put it in that six And we'll just run that there. So it's over half volume. We're gonna look at the frequency response I mean, I've very much doubted if you're gonna be playing it unless you got a real big room If you wanted to be filling the room or something if you'd be playing it that loudly In this quite small room. I mean it really does. It's it sounds good. I'm not I'm not gonna I'm not trying to hype it up At all because it does sound really good Now looking at the frequency response here, I think the main thing to take into account here is it's pretty much Pretty much level pretty much in line with each other Doesn't seem to be anything wrong here at all and DB relation to the frequency as well There's very good 27 DB, which is I think that's what they said the game was it's 27 DB Okay, so that you know you can take a peek at and Look again yourselves because it's easy enough just to pause this Across here or just watch it again as it's climbing across and now the next one that we're gonna do is the Total harmonic distortion to versus power but channels again this time we're gonna go from 10 millivolts 10 milliwatts. Sorry to a hundred watts and Well, I've got it to stop. It's 1% THD Okay, I think that's good enough for the test for this at 1% THD. So let's get that running now And again the old The old circuit is red and the newer one is the blue as well as we're coming up here towards the hundred Millivolts RMS line the power as you can see is going up in a linear fashion That's this and you can see that over there. You can see what the wattage is and you can also see the VRMS input and this has given me the Distortion levels including noise as we seem to drop down quite nicely around about four volts four watts, sorry five watts The nice thing about it everything seems to be pretty even There is slight difference there, but we're talking very very small amount Now we're in 15 watts noise levels are reducing and We're at 40 watts now Now this is the interesting part for me We will shut off up 1% distortion So we bring that across here to where we shut off is on the blue, which is the new one. It's at 60 watts and On the red one, it's actually at 63 watts now for that for me, that's pretty interesting and On the blue when we start going up real quick there. It's up 44 We're just gonna say 44 watts and On the oldest circuit remember this is the oldest thing it's up 47 watts Hmm, it's not what I expected And I am going to be sort of rattle in my head a little bit trying to figure out why this could be I May end up swapping over just just The power supplies I may feed The two different circuits are just alternate power supplies just to see if it makes any difference I'm not gonna do it in this video because we're gonna run this up in a second But I am a little bit surprised like I've sort of shown you there's only a few real differences in this and the circuit layout is only very slightly different where Maybe we could think that the capacitors here are closer to the power rail on the side Sorry closer to the power rail over here. Let me just go in one Back out a bit a bit bit closer on both sides to the power rail But I don't get it, you know these little BD139s and 140s Even though it does say in the right up at these you know, you're not really gonna find a lot of difference in this There might be just a little bit more I thought maybe this one would pull off the job a bit better It's got a thicker connections good copper cabling where this is the You know on this side, it's the It's good cabling obviously with a crappier cabling. It's not as good as that the good copper over here Mmm, I'm a bit confused But there is only marginal and there could be Other things that we can do but there are other things I can do playing around with this I can take these because I put the sockets in for these output transistors and I can put some tip 35C tip 36C's in there And you see how they do Of course that's from another video There you go. So there's the comparison everything on the setup here, you know, I'm using the one way form generator and just splitting it So that's exactly the same as what you're gonna be getting It's gonna be no difference there Everything is set up to be exactly the same and the software deals with the outputs coming in and you know, it's Yeah Well, it's been fun for me. So I hope you enjoyed that and I'll catch you in the next one. We'll get another amp circuit. We'll play around with that and see what that does Okay guys just an additional piece here what I want to say is Playing around with this for hours and hours now after making this video I can see that there are some things where things change around it doesn't all seem to be What you might think it is because when you watch this and you see what actually goes on What you can see is that there are different variations to this What I think I figured out is a lot of it is Temperature dependent. I don't mean by that is it's temperature dependent on the what? Possibly on the quiescent current But definitely down to the dummy loads as well. These are already a hundred watt dummy loads Well, I'm trying to show quite be a power through there and I do it on one and not the other What seems to happen is that? You get this Variation going on so if one of them hotter in your bow, there's more of a variation going on And that's got to be kept in mind That's it. That's all I wanted to say I'll catch you in the next one guys. Thanks very much for watching this. You've got this far. Thank you