 Hello everybody and welcome back to my channel now I just wanted to do a quick little power test on this and we'll just see what we're getting for our buck but I'm just gonna quickly show you the way I've got this connected up so just at the moment because I don't have an adequate NTC which is basically gives me a bit of a soft start and NTC is a negative temperature coefficient resistor so basically when it's cold it has a high resistance and as it gets warmer as it's being used it has a low resistance that's a pretty much zero and what this is for is to when you first especially on a circuit like this with a big old capacitor bank like this when you first apply the power this power bank is gonna load a power and the problem with it doing that is this thing is only good for two and a half amps and the power supply itself is only good for a few amps so you can really do some harm to your turns on here and cause the turns on there. This thing will suck in quite a few amps at the start and it's only for a fraction of a second but it's that fraction of a second that does the damage and these things are what prevent that from happening just by slowing down the inrush current and making it all just a little bit easier on the on the system there so for now I'm using this because I can slowly wind it up as a soft start and it just means that we don't put our stress on the system so over there as you can see so let's go so and at the minute I think we've got 170 millivolts going in there I'm just gonna put this on to 600 millivolts RMS which as you can see when we do that it takes that signal out of the range of the scope and it's graticures so it's a bit better out of the range of the scope and it makes a horrible mark on the FFT but if I am to just back that down a little tiny bit and make that a bit better we can see that the FFT cleans right the way up and we're all good so what I'm gonna do now is I'm gonna see we get a little bit closer because this is actually applying the power to it and let's see what's going on so as you can see then like I say we've got this transformer coming in now this is 160 VA but we've got to take into account things like power factors on these and the power factor from 0 to 1 on this type of load it's inductive it's not going to be as good as if it was a non-inductive fully resistive load so because this doesn't transfer the energy from this part of the AC the high voltage side to the low voltage side without costing and to be honest with you I don't think these are any more efficient than like 55% something like that maybe somebody can tell me in the comments but they're not very efficient what they are is simple and clean unlike a switch mode power supply which if you get a modern one you might be talking 94 95% efficient so if you get one 10 years ago you're talking sort of high 80s efficiency but you've got a lot of induced noise from those and that's not what you want when you want a nice audio system but you know maybe maybe you're doing a lot of classy stuff is like that anyway so that's a completely different thing so here we got our first of all we've got a an X2 capacitor which goes across the main line coming in the DC early AC sorry and that is in parallel with the upright 35 amp full bridge rectifier and this just makes sure that there's no like the line noise coming through this X2 capacitor and then we're straight into our capacitor bank we've got about 15 millifarads of sider on the left and the right it's like pushing it to every vehicle so I don't know why not they were there and here we've got our circuit I have actually screwed the transistors now to the heatsink which makes it look a lot neater rather than big ass clamps from our output there I've got a connection to the scope I've tried to do it as close as I can to the circuit because that's what I've learned that is the best way of doing it and we've got a dummy load connecting up there I've also got a jigsaw I was just trying to keep an eye on what we're going on on the output but I don't really need that at the moment the reason why I was doing that and just see what's going on over there it pretty much tells you the same thing over here 35 to 32 and all that is going on downstairs look there's the people have been doing a lot of work down there so what we're going to do now is we're just going to turn this up and just see what we can actually get down here as our output and then we can just do a quick little bit of math and we'll work out what powers coming out this before we see a clipping off tops and bottoms so let me just turn this up a little bit so I'm going up to 700 millivolt RMS going in that's 800 that's 900 that's one volts going in RMS so I'm going to just move it down the scale now because we don't want to turn that too much higher because I think we're going to start clipping any second now there we go start seeing that just chopping off on the top you can see how messy the FFTs come so let's just back that down back that down back that down there we go that's cleaned up on the FFT and if we just look across there we can see basically we've got 22.55 volts and over here just zoom into that it says we got 23.05 volts so we'll work with what we see on the screen and let's do some quick calculations and I'm just going to turn that down while we're doing that just because I don't want to be over stressing everything it's going to look a bit messy on the FFT because we're not actually putting enough signal on there that's why you can see the sinusoidal waves are very small and that's just not enough for it to do its calculations we're actually down to about two and a half volts now so rather than playing around with anything too much let's just go over here and let's just do our quick calculations what do we have we have 23 or 22.55 volts let's just do it like that so we're going to put 22.55 we're going to square that and then we're going to divide that by the atome load and we should now have our output power in watts so we've got there it says 63.5 63.56 watts so let's just say 60 watts a little bit over 60 watts which is exactly what this amplifier is supposed to give us at 8 ohms that's quite nice can't really say that's too too bad at all all right well from there then what we're going to do is we're going to do a little bit of a change in setup and what I mean by that is rather than let me just get this thing sorted rather than have the oscilloscope on and waveform generator over there I've got a new bit of kit I want to play with and I want to show you and we'll see what that says I'll be back in a moment I got a new piece of software now I'm using Linux and you can't actually use this new software in Linux I'll put a virtual machine in and I'm using it within the virtual machine so let's just make that a full page and I'm gonna tell you now what this is this is my new bit of kit for the bench this is basically a board for audio it does have a whole bunch of other capabilities but I've bought it to get around some of the issues that we got when we're trying to use the FFT and audio measurements on an 8-bit oscilloscope and that's basically this say an 8-bit oscilloscope you can do it you know you need more bandwidth in you need more bits and this thing here is a 14-bit USB oscilloscope now it comes with or you can get free with it from Digilent some software called waveform and this is the waveforms here but I don't use waveforms I use waveforms in order to calibrate this thing because it's got a bit of a calibration process so you got to go through but I don't use that I'm using a piece of software from a chap and Jake his name is and his this piece software is by the Stuffmade now the Stuffmade is a YouTube channel I'd say if you're into your audio you'll want to look at this sort of software in that go there he's a great fella I had a couple of questions he answered straight away for me which is really brilliant and it's allowing me to progress with this now what we're going to do is we're going to go I've just got on the spectrum analyzer part here and I just want to say straight away that look you can see with a noise for always down a down a hundred and the highest peak that I've got on this is a minus 72 minus 73 point 2 dB now we're going to do a couple of little quick measurements on this the actual amplifier is on it's all all go there with the connector block down and amps on there you see the little green LED slightly illuminated power supply of course we need that and what we're going to do is because this isn't going to look very good so we're going to use the screenshots of this on recording in Linux I'm recording the actual screen of this and I hope it does work out to you know to give me the actual screen and not just inside Linux hey it's all a big learning curve and we're going to find out together so we're going to go for this first of all THD noise versus frequency and what I'm going to do is I'm going to set the level to 1 watt and in actual fact what I'm going to do is I'm going to set the level to 5 watts yeah we're at 8 ohms this is just the range for the top that's a plus 10 percent distortion we don't we we're not going to need that I don't believe but the highest we go is is 1% there so we'll have to put it at 10% and the bottom is 0.1 we can have another order of magnitude and then again but I don't think we're going to actually be needing that particularly here we're going to go for the THD of the distortion side of things and I've given it a band with 30 hertz and I'll tell you what that will be in a minute averages one I'm going to put the average to two and we're going to have 50 steps on this and please forgive the banging it's probably the nicest it's been for the last three days but downstairs is having some work done in the bathroom a new bathroom a new walk-in bathroom very nice so let's this was a measurement I took a little bit earlier when I first just started the amp-up but I've made a few differences like I've switched from times 10 on my probe two times one so let's run this it's going to take a few moments just to get it going especially at the lower frequencies and then we'll see the start coming across the screen so here we are this is at a 26 hertz now we can see the marker and we're at like 0.08 percent which isn't terribly great and 0.06 I do that little dip and this is remember is at a five watts of power going through this and I can see over on there I just show you quick what's going on over here you get to see what's going over what's going on over there as that runs through that is the AC voltage on the output a bit more seeable okay well that's that completed so that's the that's the noise as well as the total harmonic distortion so let's just put it down to be in the total harmonic distortion on this one without the noise and again we're going to run it at five watts I'm just gonna let that start doing its thing at the lower frequencies it does take a little bit longer to to process it okay so we started off down there we're at 30 hertz now at 0.05360 percent 0.04 it's quite nice it's good to 70 hertz I do like the idea on the bottom left you got the spectrum analyzer and you get your scope of course on the right hand side I do like that but the spectrum analyzer at the moment is most things are there sort of like around about 70 minus 70 any anything else you can see in that now there's gonna be things there's gonna be things from this entire setup you're gonna see me you're not gonna get you know this I suppose unless you spend a lot of money a pure type of thing going on there so it's all cut as I find about 17 17 kilohertz there so but that's quite nice you get to look down and we get to go all the way back to the start and have a little look what was going on there at 20 hertz 0.06991% go a bit further in we go here 25 hertz 0.58 and of course we also get to sit down here so we go for that because that's our where are we there that's at 80 80 hertz but even that's minus 66.6 more than 66 is a 666 69 we look at these peaks there that's minus 78 nearly minus 79 there so it's good it is a and it's all below the 0.1% line which is which is pretty good pretty good now we can look at a THD versus power I think that asked you up to 100 watts now so I'm gonna do I've set it for I'm gonna put it onto 1% distortion where I want it to cut off like I don't want to I don't want to push this too high and I'm not even sure if I can without breaking this device it's gonna be the first time I'm gonna push it if I can to 100 watts make sure our load impedance is 8 ohms which it is I'm just gonna do a quick temperature check that's well on the dummy load there's nothing there's some warmth on the heatsink to the amplifier but the dummy load is actually cold so we're gonna give that a go then and we are gonna be doing stopping at 1% bandwidth is gonna be 20 hertz we're gonna be going from steps 50 yeah can we go we start from 1 watts all right just bring it straight in at 1 watts I haven't done this before so this is gonna be well this is gonna be whatever it's gonna be let's give it a go let's just start running that okay as you can see the power is rising we're still under like 1% under 0.1% I should say and we are at so we're at 10 watts now 0.06 on the THD and noise this is noise as well we're at 40 watts whoa not quite 1% 63 watts okay but this is only good for that amount of power because in the measurement I shown you before we did Bob was it 22.5 volts or something was it 23 volt I can't remember I'm sorry but we're good for 63 watts so that tallys up quite nicely with that and then we got into being at 1.064 percent distortion which is it's cut out because it is gone above now let's say we get that under 60 we're still 0.8 and down here we get to be 0.7 so that's at 50 watts but the jump is above above 40 watts we start going up we're not quite on 1% distortion yet but below that we're below up to 40 watts we've got a distortion of 0.055 percent and that's at 40 watts that's pretty good I mean I don't think I'd begin it to do any more work and that anyway to be honest you're in this small room that's fine I am thrilled absolutely thrilled with this software too I'm thrilled with this because it is going to open up new doors you can play around with employers and testing them and yeah I'm I'm thrilled with this particular circuit anyway it's it's still below 1% distortion all the way up till we get past where I know it clips anyway and that's what we're seeing that's what it would have been seen straight away and I've just this thing's got a built-in cut off I set it at 1% distortion THD and that's exactly what it's done it's cut off there beautiful so I can't damage anything I am thrilled so look guys are we're going to do one more test actually we're going to do a frequency response and we're going to do that out round about let's say we're going to do it at a one one volt RMS a frequency response right so we're going to go in from a range of 10 to 50,000 Hertz so I know it's high we need that but we're going to do that across there anyway and we should probably change that to 30 let's change that to 30 and this is just our range top to bottom on DB and we're channel one and let's run it let's run our frequency response to see what it's like at one volt across the frequency okay what we don't want to see is deviation doesn't really matter what the numbers do we just don't want to see it deviating all over the place we want to see it go into a pretty much level area and then stay in there all the way to the end and if we get that I'm going to jump around the room didn't look it is some weird noises coming out the other thing but yeah so well we stayed within a decent parameter there what we got there we got a 0.69 dbr at 27 db which is wow that's pretty much as we can run this thing actually 27 db that would equivalent to what it said it was on the game that's 18 Hertz and we started off down here at minus 0.41 but remember that we were running that at a reasonable rate and not so that's one one watt of power one volt of power all right let me just do this just one more time and this time we're gonna have a little look over here and see what happens on there look at the voltage all right that's just as it got game with the higher with the lower frequency was at the higher voltage let's just run that that's peaking remember 22 volts 22.5 volts is what I could get out of it so this is absolutely peaking at that one watt VRMS oh it wasn't happy there was it and you can actually hear that I think all right so we're not gonna push that any harder on there and the result is pretty much the same anyway we've still stayed within that area which is less than the db of change so that's all good and our spectrum analyzer if we just put that on for a level this is at just under a volt we should probably go to something that's a lot kinder to it let me just feel the temperature temperature the heat out the dummy load that's very very hot I tell you what I'm gonna call that quits for now we can look back at this and do some other in-depth stuff if I think there's anything really worth pointing out but just for now I'm gonna say let's just do a quick single shot and we get to have a little look this is a 70 dB down here and we are measuring over there minus 73.5 dB at 2 Hertz this is our fundamental that we're putting at a point to VRMS at one kilo Hertz okay well guys have you got this far I hope this has been interesting to you and this is hopefully just a start for me playing with this audio stuff and thank you very much to Jake out there and the stuff made that's a big thank you because without this software this wouldn't have been possible and yeah I will catch us in the next one bye for now