 Hi everybody and welcome back to my V-LOG my channel and on the bench today we have the Quad 405 and this time it's like a revised edition and this one has the I think these are 246s but they're the silicon transistors rather than the TO3 packages which were the metal the old type metal so you'd think and you'd hope that inherently with the new packages you will get a hopefully a bit of a better bit of a better response from it all around this is what the circuit looks like built up very nice very clean we have our connections we've got a negative coming in here feeding the negative side of our power supply we've got the positive side of the power supply here and here just move this out slightly oops this thing always does it a different way and here we have the virtual ground going to the ground but that also goes to the dummy load negative side it also this is the virtual ground connection it's red and this black come from a power supply we've got the dummy load side and it's also the output for the speaker of course that's whether the dummy loads connected to and here we have the output itself to the speaker which is going to the side of the dummy load and this part of the scope input side we just have from our WaveGen and we're using the like get that in the picture the analog discovery 2 from Digilent it's you know it's just better for these sort of jobs one it's a it's a narrower bandwidth on it frequency on it so it's less like to pick up other noises and two it's 14 bit which works out better than the 8 bit oscilloscopes it can see a bit more depthy into the noise levels and everything all right so I've got that connected to my power supply please forgive it's a very busy bench and I don't have time to put every single thing back when I'm using it so things just tend to get pushed out the way 10 minutes ago 15 minutes ago there was a quad on here and that had to be quickly put back together again and now it's like this so it's just a busy bench so we connect up the power supply there I'm just gonna move my tripod and screen here so we can just hopefully get past my cat who's down on the right hand side right down there by the floor great stuff where I can run him over with my chair and right just before we do that we're gonna look at the screen and we're gonna see what we've actually got here so you should be able to see they're on the screen now Aliexpress at the minute there's a 33% reduction I don't think these were over 30 pounds 97 for you as Americans out there it's gonna be roughly the same we tend to get the same price in dollars you buy for stuff over there and we get charged pounds and I suppose that's because of our taxes and everything else I'm not sure but we seem to charge more never mind so yeah I bought the kits personal I prefer the way I you know put the things on in the kits I make sure all me it's neat like this would just never be any good for me where this is raised one part of the board not yeah it's gotta be it's gonna be neat for me we've got it's not gonna let me change that it's not gonna let me change that no okay here we go here we go so this is the audio precision what it states so here's our one kilohertz input signal you sit on there and it's showing a very very low noise floor we got a little bit of a silent there at 15k but it's quite often see those sort of things so that's nice that looks very very nice indeed here's the frequency response and as we can see 20 kilohertz which most of us won't be able to listen to anyway we've got a minus 1.5 deep B against the voltage reference and then it comes up it sits underneath line that could just because the way the scaling is done here even though it looks yes because the way the scaling has been done here you'd think they'd do it so it was like three each side or two each side so that zero was right in the middle of this line would go along with a zero maybe they got the reasons for doing it like that I don't know but over here see we got a this is 0.5 so at 15 kilohertz let's say between the 10 and the 20 there drops down 0.5 and at 20 kilohertz we're down to I think that's one yeah minus one DB but that's good now the sunlight's coming through and we can see flashing on my on my other screen but no one it's like I say 20.75 get all this about express those other things out there so what's it say about power wise the kit consists of two dual channel board including all components of high power tubes as well as insulation sheets and particles all parts are brand new in genuine the single amplification transistor adopts the original imported BC 556 and the 5551 and 54.01 audio dedicated signal transistors the LM301A brand new NS which is virtual semiconductors all resistors are made of genuine metal film resist the copper pins with 1% accuracy including the high power resistors the power transistors are brand new imported ST 2 SC 5200 power transistor so we got the drive the drive which is KTA 1659 the inductance is manually measured with the precision digital bridge accurate to 0.01 micro Henry 0.1% accuracy there power supply voltage is or equaling to plus minus 30 volt or it wants less than or equaling to plus minus 50 volts PCB size is 55 millimeter 75 millimeter wild and the power can go in as 50 watts to 100 watts at 8 ohms kits loose requires yeah so that's and now we're just gonna get the same information so let's just you know get past that they get like you get to see the kit they're very nice and just gonna present you with all the parts very good of course you get both channels so you got a stereo going on there all right let's get out of this we are now in Windows audio analyzer suite provided by Jake at the made that the stuff made which is an invaluable piece of kit here and I can't wait for the new one to come out and then he's full recognition for what he does there he's absolutely brilliant right so as we can see we got this on the go now first thing I'm gonna do is I'm gonna use my power supply to power this on I'm sorry if you can't see the screen very well over there the way the sunlight is coming through it's nice to see that we're not flickering anymore sometimes we get the flicker come through so what I'm gonna do is basically turn it on so I've got both sides on so we got a negative and positive supply here and I'm just gonna gently ramp this up because I've not turned this on for a while and just make sure there's no issues with it I have checked and door check my cables so we should be okay and as I take that up I can see that yeah we're fine we're not drawing any more than what would be expected okay so I'm just gonna let that just settle for a minute or two don't worry about it I'm gonna skip forward on that and I will also try and get rid of the flicker so guys we got this setup this is set up now 10 30 kilohertz and steps averages 8 ohms 0.2 volts channel 1 total humming distortion and the noise let's run that all right so I'm not quite sure what's going on here on this if you look at the spectrum analyzer down here we can see that the noise level has gone up you know I saw this minus 60.5 dbr there at one one kilohertz but it's not quite that is it 899.7 hertz not quite one kilohertz all right you know we've seen better that does look a bit funny I've got two channels two of these channels made up so I might check out the other one and just see if it is you know the same so let's just get rid of the noise and we can see here that 20 kilohertz that's nice looking pretty good that's 0.07 that is pretty good we get down to just this little bit before we got there we've got 0.05 this unfortunately is 0.123 down here again 0.05 there again on that peak 0.0 0.10 the lowest part is pretty much here which is 0.04 which I suppose does give the classification for like high-five quality down there let's have a quick look at this second harmonic okay that's pretty good highest peak there is 0.06 0.07 0.08 now about the third harmonic oh well yeah this is this is a little bit strange 0.02 and down here look at this look 0.00121 I imagine if we could just use that for the advertising I'd make it look pretty cool yeah so that's that's what that looks like I'm sorry I can't do anything about the way that is not exactly sure why it looks like this here I'm gonna have to go look at some other videos maybe if people don't test on this and just see what theirs looks like so let me have a quick look at our what we could do the power versus or we can have a quick look at the scope we can stick that into square wave channel one again at the same level going in point two of a volt on a mess and 100 1000 hertz as well let's just do a single hit on that and take a peak oh we've got a bit of trouble boost there and just sloping off a little bit on the on the base side of things but not much nothing worth you're really talking about is let's go down to 100 to a quick peak at that and it's it's not as good as what it could be but I don't think that's particularly too terrible I would be got these little peaks here this means that there's a little bit of added treble let's just bring it down to let's say well we're gonna look at 20 anyway just because that's the audio range no other reason I'm just taking a quick peek at that all right yeah that's not working out so well is it it's not working out so well I'm not sure that's phase shift or not all right let's let's have a look at let's have a look at 40 my speakers go to 35 Hertz let's just take a peak at 40 all right I mean not brilliant but it's not not that terribly bad either I don't you know I don't seem to be as impressed with this I'm gonna go 60 now I hear on the Hertz quite a few people got speakers again 60 Hertz that's not too bad it could be worse it just dropped off all the way down here yeah you know I'm just showing you that's what's going on here I'm just showing you so I don't know if this is actually performing worse than the other ones with a to three transistors on the old ones I don't know but let's just let's have a look at 500 Hertz here there we get that yeah you know it's looking around like the same as the thousand so let's go up to 10 kilohertz oh let's do five actually five kilohertz not 50,000 five kilohertz distinguish shot on there all right this again that that bit of travel was always in there isn't it it's always got a little bit of extra brightness going on not much but it is added brightness I will look at 10 now there's a single shot on that look at 20 oh that's not very good cross over there let's just take it to 30 and just see what we got going on there almost got a sine wave a bit of a notch in bit of but there but I take a peek at the frequency response same values on the power and everything again I'm just going to bring this down so it's easier to read for us all so they are equal amount of db 3db negative and then 3db yeah 3db yeah you'll see the way it's done here all right then oh you know that's not too bad if we look over here at the 20 kilohertz I do believe it said 0.5 on there isn't it's 0.6 here if we get up to our 30 kilohertz 28 0.1 yeah see that's pretty good it raises a little bit but I think that's that little time with the treble we can see in the square wave and what we got and we started strapping off 0.3 and that's at 20 20 kilohertz you see so that's not bad there that's at 30 kilohertz 0.0 0.86 so all in all I mean it's not bad across across there doesn't look as good on the square wave on the square wave does it looks a little bit now but the square wave doesn't determine the sound quality it doesn't determine the sound quality just helps you easily see some things you know this is a bonus for the frequency response here all right let's do a let's do a power test on it that's the one that a lot of people want so we're going to take that off a thousand watts now because as well as testing last we're gonna do steps yeah yeah 1% stop and we're gonna put a load impedance the way times there all right so we're good to run let's do that okay dokey well that's not totally bad let's go for we did a little crossover here around about 0.1 percent distortion about 5 watts 0.1 percent distortion again keeping that it's dropping below 0.09 percent that's at 10 watts we get here to 20 watts 0.05 percent distortion so yeah listening between let's say 20 20 watts there and 40 watts 0.075 percent distortion pretty good we only hit up 1% which is here the magical mark which is there at 52.75 watts remember I'm only putting in we got 32 volts per side so in total 64 volts for the entire swing from negative up to the positive peak or crest and then back all the way down again to the negative side of our power supply so that's not bad that's not bad at all if we look at the crossover part here at 51.36 watts watts we've got a 0.373 percent distortion on there so not too bad not as pretty looking on the on the spectrum analyzer I'm going to check that signal in there just don't just do a quick oh no so I'm not the spectrum analyzer on the square wave even at the highest and certainly not as not as pretty as what we might like around about let's say 50 50 Hertz remember guys these are old circuits from back in the day back in the 70s and they were not designed to give you just you weren't gonna get the range and besides even if you could buy an amplifier which would have been really expensive and then you're gonna be able to match it to some speakers and to get the full benefit of an amplifier that can go down to let's say you go down to 20 Hertz and it's lovely yeah to get the full benefit out of that you got our speakers that will that will reproduce that for you the chances of most people wouldn't have been able to have that so this would have been okay like I said before on these there's a bit of a there's quite a few people actually make these into put them into cases and such I don't know if it's just because there's no nothing else around when they decided to do that but I've listened to them and I tell you what when you it's connected up to like a movie and stuff on the TV just plugged into you know output from the TV into it sounds nice even the music sounds nice and it's quite hard sometimes to hear the differences there are subtle differences but this is all gonna be down to how you like to listen to your music and that's a subjective thing well I'm trying to show you his objectivity just as you know this puts it out and all I can do is use the kit that I've got so everything is obviously I'm using the same kit I'm not I'm not switching out between different waveform generators and the different scope I don't want to do that I want to use exactly the same kit set up in exactly the same way to get these outputs as a comparison against this rig setup all right a different setup may give slightly different results that's what I can say all right so this is the end of this I tell you what I will do if you've got this far I'm gonna say thank you very much and what I will do is I will set up another one very very shortly I'm still trying to get my quad up in the air and I will set up my quad as multi rotor for some viewers you get confused when I say quad they think it's an amplified quad and it's not it's the multi rotor and I will do a comparison I will use the TO one thing I'm gonna do anyway in the background is I'm gonna check against the other circuit identical that I've built and I'm gonna see if the other little anomalies within the frequency is these bits here whether they are present in the other circuit they'll be interesting to see even if it's just for myself but I think I'm gonna add it into the next video because I will do a comparison where we can overlay the two outputs and just see what the difference is between the TO5 and these these chips here the SC2500s I believe that's what they are and these oh it's the 247 packaging that was yeah I'll stick it up on the screen so still it still it's me all right right so thanks for watching and I'll catch you in the next one bye for now