 Hello everybody and welcome back to my channel. On the bench today we have one of these. This is a hood. So that's someone, Lindsay Hood. I can't remember the first name. If I remember it I'll put it in there. And this is a circuit that's being chopped and chained and modified and all sorts of people have been working on this and there's forums out there that you can go and look at to get suggestions and ideas about this. This is the single rail. So it's just a positive and negative input AC. A lot of the other ones there's been some conversion to dual rails. We've got a positive and then virtual ground and then negative. This is not one of those. This is Waterfally Express and it's actually brought as a pre-built. I thought it was going to be a kit. I didn't read it properly but it's a pre-built and that's fine. It's a class A amplifier. So it's going to be pretty intense on the current but it's got place in history and it's I thought it would be a worthwhile kit to take a look at. So I've already got mine over here on the bench. Oh let's just quickly, quickly let's just have a look on the website. You just see what it says on the screen here. So on the screen we have it here. It's all it's glory. There's a few changes past there. It's a different color. Same sort of thing though. Oh that's the one I've got on my board. It's 3,300 and this is a 6,800. So there's a difference there. The nichicon according to the one I've got on my now. This is two boards. Just put them together if I just do this to the one board like this. We can see this 202 right next to this. It does talk about this. I'm sure it says some about LM317. I don't know why it says that because it's not an LM317 on here. That's actually a tip 41. Tip 41 C to be exact. That's a tip 41. But see this behind it because you'd be looking this way because this is your input. This is your output for your speaker. On the other side of this tank pasta is the AC input. And this here, this 2K 202, this is to adjust the quiescent current. They suggest run about 1.2 amps. Some suggest a little bit higher 1.4. And this is a 204 I believe. And that is for adjusting the voltage. And you do that by putting the positive side of your probe, your multimeter probe here. And you can go into the ground. I think this one's ground here and this one's ground here. And you can just see what the voltage is there. I'm putting in 24 volts. Mine I've set mine to be 12 volts. If you do 18 volts in, you know, 9 volts and so on and so forth. So yeah, so that's what it is. And there's a little bit down here that just tells you how to do that. And it does say here the voltage range 12 by AC to 28 volts. AC 2 wire. So that's a single row. 50 watts or more. But I'm going to tell you now that these heatsinks get incredibly warm. I mean, incredibly warm because mine's set up for about 1.2 amps. And we're going to take a peek at that actually, because I think this is quite dependent on temperature as well, the way this is set up. It's all quite close. And these are not the greatest 10 kilometers. You can be twiddling it. It's going down and it starts going up as you're still going down. You're supposed to be going down, but it starts going up again. You've got to find that little area where you can get it to stabilize out. I suggest maybe you get some better ones, Borns or V-Share or something like that and put them in there. And the voltage not so bad, but on the current. It does play around a little bit. So on the screen here again, it says they're using the 5200 high position, high current regulator for the output beyond 317. I don't know what that is. Even more inaudible. Using the Thunfilm audio capacitor. Sound is better because they've got this big old weiner here for the input capacitor. A Shiba, a big tube. Yep, lovely. Look at that. But this is the bit, the debugging method. So 969 commission divided in static. Yeah, yeah. One, the quiescent current has to be adjusted to home. Has been adjusted to home default 1.2 amp. Mine wasn't like that. You can change your quiescent current by just in the 202 adjustable resistance on the board. It's the one I pointed out to you. And recommended 1.2 amp. In addition, the quiescent current needs to be tested in series with the current input port. So what we're doing that there is, we're taking our output here. So this has got two 12 volt outputs. And I've just connected the two middles. So we've got a 24 volts. It's connected in series. I've run the one side in the return side here on the negative. And I've got my plus side coming out here going into my multimeter over here. An ultra factor free, just a little bit better. Getting into the multimeter at the back here. And of course it comes out and does the return feeds into this side of the AC input. We can turn that on now actually because in a moment we're going to be, we're going to be switching that on. All right, can I say that? Is that going to be good enough? There is more. Got this piece of white paper there because there's a lot of reflection off this. Yep, you can see that off the silencer upscreen. And it's annoying. Oh, it's me twidlisting. Right. Well, so yes, there's our, that's for our current side of things. And then we got the two, the midpoint voltage test, the midpoint voltage needs to be one half of the power supply, as I explained, 18 volt, nine volt. Me, I'm using 24 volts. So mine would be 12 volts. Line test can be just a resistor. So yeah, you're going to put the positive probe to the output here, which is there on this bit here. Just look on the side of that. Just make sure I'm not doing that wrong. The positive probe can go here, which on the, let me just show you. And now you see it there. Let's go a little positive. See that there? A positive bit there. And then we can just go on to the ground part there. And now we will be able to see our voltage. Now just this is, wow, we're seven minutes in. I'm sorry about this. But this is something, well, something I just wanted to see. I've got this set up here now and it's running in the background. And this is just, you know, what it's like as the system has sat here and it's all connected up. And I want to put the power on. And I just want to see, you see, this is my 50 hertz. We're going to get some 50 hertz noise around here. I can't really help it. This is my 50 hertz. And I just want to see, now this is, just in case you wondered, this is down at minus 180 here and it's 160 line minus 160. It's where we got that noise sort of level up the moment. And I just want to see if there's a great deal of change as this warms up. It's going to take a few minutes. What I'm going to do is I'm going to put down this connector block and then I'm just going to let it warm up. I'm going to give it a few minutes to warm up. Right now I'd like to be able to have a temperature probe. In actual fact, what I'm going to do is I'm going to remove this. I was going to use that to show the voltage. I'm going to remove that. I'm going to stick a temperature probe in here because we can do that on here. Let me have a look. Yes, we can. So here we go. I'll just set this temperature probe. Let me put that there. And if I can put that there, can you see that? Without too much reflection. You can see that. I should think it would be good. Yep. And now what I'm going to do is I'm going to, that's just me. There's no way I'm, well isn't that bizarre? There's no way I'm 31C. Absolutely no way. I mean that makes me incredibly hot. So I'm just going to, there's a little tiny hole back here in this heat sink and I'm just going to wiggle it and see if I can get my, do you know Darnit? I'm just going to put it in between the grooves of the heat sink. So you can see that, that is now, give us an indication. It's not the most precise. This one's better but we need it for the current indication on the temperature. And now I'm going to turn the darn thing on and have a little look at the temperature. But the main thing I want to be looking at is what's going on at the screen. So I may just, you know, I'll bring the temperature into a top left hand corner of the screen somewhere. So here we go. Let's put this down and hopefully my cats haven't been doing anything too crazy on here since I set this up. It isn't going to go bang if it does. There we get to catch it. On camera. Okay. It's on the screen that we can see there as that's kicking in. And you can also see the current being drawn. It's just over one amp at the moment. But you can see on the screen here, look at all these, like these are all multiples of this 50 Hertz home. So we've gone up from the 160 line that we were resting on. And that was below the 120 I believe I can't remember. You have to think that so we've gone up like 20 dB. And all these are multiples. So I've got a funny feeling we're going to hear some audible hum and I will connect it up to a speaker just so we can have a little listen at that. You can see the temperature. We're up to 20.8C, 20.9. And it's going to take a little while. It's going to take a few minutes. So I'm going to shut up now and I will just speed this up in the actual editing. Let's have a look. So yeah, well, you know, it's been on for a few minutes now. I'm pretty sure you can see a little blue light, a little blue LED on in the background there. I'm not sure what that's for. Maybe just to let you know it's on. You can see the temperature, 38.2C. And at the moment it's got to this sort of area with it's warm. Leaving that on, it's going to, as you can see it's going on a little bit, going down a little bit. But that could be because, you know, I've had the front door open and I've been sat outside with my cats. But the temperature thing there, that's an interesting thing because at 38.9C, soon we're going to be on 40C, we have a degradation of those performance of those transistors. And the higher that temperature goes, the more degradation we have. I find that word hard to say of those transistors. But I don't think we should be too worried about it. But after 25C, which is what they normally set, they give you the stats running at 25C. That's what you're going to get. Yeah, the outside of those is sort of quite cool. Yeah, I mean, it's not that bad, actually. It's warm. It's not too hot to keep my fingers on at this minute in time, as we can see. By this, I think that's still going up slowly, goes down a bit, then it goes back up a little bit and down a bit. That could be because of the ambient thing going on, or it could be just because like I said about the pot here isn't very, very good. So right, what we're going to do then is now we've got it like this. We're going to have a little look at the total amount of distortion and the total amount of distortion noise. As I point out before, here, these are all multiples, 100, 150, 250, 300, 350, 400, 450, let's round about 500, I don't know what this is doing there. But on these lines, you can see where you'd be going from 250 to 3 if we follow the lines here. And it's like it goes all the way through. So I've got a funny thing when we put a, we've got to stick a speaker on to see if we can hear any hum. I expect a bit of hum. Let's see what we get. So let's start in the volume up. See our signal going in, we've got a bit of a spur on the 2K there. Let's go straight to 15. Now, these particular amplifiers are, this is not full blast listening amplifier. Okay, I mean it would be great for it to be like that, wouldn't it? But it's sort of emphasized that these are, you know, sources. You know, you've got to use your common sense with this sort of stuff. You can't expect this stuff to have been tweaked that well to give it right maximum full range. And as we can see here, 15.5 dB of s, which is a lot better than 20, but it's 0.094. Right, and as we go to about 10, I'd say 10 is going to be the sort of area that you're going to be listening to it if you're listening to it. You can already see this distortion right here. Look, isn't very good at all. It isn't very good. I bring that back down to there. Let's say the, let's get it down to the 0.1%. All right, let's just say there. So I reckon you're going to be listening to that. That's 42. I don't know what we should probably try and do is just do the input voltage of my input signal. And then the output voltage signal. And then we can do a divide on that to see what the gain is. But I need another meter. Give me, here we go. I'll use this little dinky, dinky Breiman. I think this came free with the, you know, I think this came free with the power supply, the Rygel. So where can I put that so we can see what's going on with this? I'll just balance that there. Can I? All right, so let's have a look at our input voltage. Yeah, that's my cut. We have to just 0.377. I'll probably do that so you can see that. I know people prefer to see things rather than I know what I do. Let's do it again. So 0.377. You can see that down there. Just to know it's not that easy, but we just have to live with that. And then we're going to go in and we're going to have a look at the output on there. It doesn't really matter about me turning it around. And then we can see a 4.4, 0.377, 4.41. No, I don't have a calculator. I can actually do. So I'm going to put that up on the screen, what that is. The, that. So what we are now we're on 44. It seems to be stabilizing out there. And I've got a funny thing we can turn up that quiescent current just a little bit. And I don't think it's going to give us much more in the way. Let's just have a little quick look again at what we are on 42. 13.2, we're on 1.5. And that's at the volume 42 here. That's just a quick way of me trying to work out what's what. Now where's my little twiddler? I lost my twiddly. All right, we'll have to get in with the screwdriver. And hopefully I won't touch this when I'm touching that. This is why I like my little twiddly. Because it's got a little, like a, you know, a sheath around the little thing inside. It is one I want to open on the other end but I prefer to use this. So I'm just going to use that and I'm going to turn up that quiescent current. I'll give that a few twirls. So part 12. But this I had it dead on the other day. I know it's, I see some recommendations, you know, or 14, they say 1.2, others say 1.4. So I was going to leave it there. 1.2.6. Now what we had was volume 42 and we also had 0.15 and we're on 30.2. So now we've got 0.11. All right, so a little bit higher on the quiescent current does give us a little bit better there. But of course, our heat has gone up to 46.4. So let's just bring that down again. Now let's have a look at the, on four of my story. I can't remember exactly what it was. What I'll do is when I've got the laptop on, I will put it up in the editing. What the form is, you can have a look for yourself. It's not exactly the same because there's been a lot of changes made with this circuit. People working on it. So 1.37, who cares now, as you can see here, look, we're on 47.2 C. But let's go back to 42 because that was our best sort of place. I'm just going to keep it on and dodgy going on. We've got these a lot around here, isn't it? 42. Now look, we've started at 13.2 dB first, but we're at 0.091. So in the respectable area, 0.1, and below is good. It's respectable. We turn that up a little bit. Point one, we can go a little bit louder before we start getting into the 1%. Straighten the 5%. Let's bring that down. 1% THD, 0.2, and we're up 52 on the input and nearly 50 C on the temperature. So the person who suggests 0.4 then, 1.4 amps, quiescent, yeah, far off. Let's just give it that give it that 1.4. This heatsink that I'm using, is it going to be very warm? All right, so there we go, about 1.4. I mean we can see 48.7 and that's making me sure how well the tip of my probe, the temperature probe, is actually touching that. It might be just balanced in the middle of it somewhere, so I think it's going to be warm. And all the way through this, look, 0.06, I'm at 14.4. That's a good listening volume. We're at a 38 here. That's a nice listening volume. We're doing it slightly better there on our 13.2, my 13.2 dBFS. We're at 0.08, now it's at a 0.9. And let's see if we can get any better than 0.5. We're about 9. After this 9 we started shooting up to see what we get there, because it's quite hard to get at 1%. So there, I mean, that's going to be pretty loud for anyway. I've added some extra little spares around the base of this. But anything louder, like there, we look at this, look at the whole money, it's just dropping off here nicely. It'd be nice if they weren't there, but they're there and it's just dropping off and it is all from this. All right, that's that. I think for now, I think we've just covered to have a look at that. If I leave this here and go for a frequency response, hit that and see what we get. All right, let's see if I can move this. I sometimes have a problem when I have to move this around like I have now. So what I'm going to do is I'm just going to turn that up a little bit more and hit it again. It should, there we go. And let's see, let's remove it now. Yes, because what we want to be able to do is just go in for the what am I doing? Come here. I want to be able to drop this down. So that's too much. We want to get it. So we've got, let's just drop that down to 10. Bring that back again. That's 20. Let's drop this down. 25 and bring that back. Just trying to get it as close as I can. We want it on the 3 dB. We can have it like that. As we got the 3 dB side, roughly, I'd have to turn that up again. Right, so let's have a look. I'm trying to make this as fair as possible for it. Minus 3, 12, 10, 11, 10, 9. And we're going to, so we got, let's say this is just 8 and then we've got 7 and 6. There's 3 dB there and 8, 9 and 10. Oh, 7 to 8 to 9 to 10 would be 3 dB. So a couple of dB each side to here, that would be that one, the 8, 9, 10, 11 and you know, to the 5, so that's 3 dB there. That's good enough. So we can get to see then, if we bring this in, we just put that. Oh, come here. Thumb work like that. And we're going like that. So we get to see here that we're dropping off about 1.5 dB on our 20, but at 30 kHz, we've dropped off. What's this here? Let's just put it to there. We'll have a little read minus 7, 5, 8. And at 30 Hz, we've got minus 8, 1, 6. So 7, 5, 8, 1, 6. It's not a whole dB. It's not a whole dB. And 40, 7, 5, 6, 1, else something. Yep, 5, 8, 5, 6. It's better. About half a dB drop off there and that's about 40 Hz. And hey, how many of you got speakers are going lower than that? Or in the 30. So that's not going to sound too bad. And if you change the input capacitor, you may find the bigger input capacitor, you might just get a little bit better on the old and a better quality. I mean, it says Weamer on there in town now. But I'm sure looking through the forums, I saw other people have been trying different types of capacitors, oil and paper and stuff, and they were saying there again. And even tantalum, metalized tantalum resistors, and they're saying they're going to get a better sound response, tighter bass, extended bass on using those different things. So you can see that's not terribly bad at all. Not terribly bad at all. So yeah, in conclusion, for the class A, I mean, it's running a bit warm and it does run better when it's running at a higher quiescent current. We could see that. Oh, let's just turn that off again. I was expecting to go there. If I kick that straight in there, that point, you know, the point 1% ish. And then point two, I'd say that's pretty reasonable anyway. There's a listening volume because you're not going to run in these four blasts. These are going to be for like just a comfortable listening volume. Nothing too loud and raucous. And I think you're going to get a nice, pretty much a nice sort of linear response out of these. And this is what makes this sort of thing better than like the FETs, for instance, from what I've read, the linear response. Okay, that's it. I just wanted to show you that. And quick little how you set it up and what you should expect from the temperature and such. A bit of a longer video than normal, but if you've got this far, thanks a lot for watching. And I will catch you in the next one, guys. Bye for now.