I have followed this video to build a class D amp. There's some thing you should know if you also want to follow this video. the 1nf capacitor at 555 timer is used to convert square wave into triangle wave. In my case 1nf is to small to fully convert the square wave, you should hook up a oscilloscope and swap a few different capacitor until you see triangle wave. R3 (2k ohm) is used to control the frequency at which 555 timer oscillate. I'm not using TLC555, instead I use NE555, in which case the frequency is only 2k Hz if I use 2k ohm resistor for R3. To solve this, you simply replace R3 with a 10k potentiometer, and see what resistance is required to get 200k Hz. I added a 1000uF capacitor in series with the speaker as a coupling capacitor to block the dc at output stage. Any way, thank you @GreatScott! for making all the awesome videos about electrical stuff. It helped me a lot. Keep on
For sure I feel the same sir. I wrote a essay to compliment him. I appreciate people like you. I enjoy electronics so much its more than a hobby. I consumes me. People ask why I do not buy this stuff and I just cant. Although, I cant because I enjoy making it myself. I will spend 4 hours to make a $5 device. I am glad you complimented this gentleman in this video.
@@retrorocketman6969 No freaking way. You just described me to a T. I take everything apart and salvage hardware, fasteners, heat sinks, transistors etc. I needed a magnetic heated stir plate so I built one. I built the amplifier and sub in my van. I think anybody could buy one. Not too many can make one. I have a 22 year old zero turn mower that runs circles around new ones. I feel good about repurposing junk. It is more than a hobby. Kind of an obsession. I'll fall in my own coffin with a file in one hand and a soldering iron in the other. 😁
You don't happen to have an old set of cabinet speakers lying around, do you? It's amazing how much an enclosure can increase the sound output of a speaker.
i guess Im asking the wrong place but does anybody know of a way to get back into an instagram account? I somehow lost my password. I would appreciate any tricks you can give me
@Anakin Rudy thanks so much for your reply. I found the site thru google and im waiting for the hacking stuff now. Seems to take quite some time so I will reply here later with my results.
The reason there is no FM on Shortwave ( Or AM and LW) is because the band width is not there that is required. Broadcast FM takes up nearly 200 Khz of "bandwidth" (Which also accounts for Guard bands, frequency deviation of the transmitter, and the bandwidth of signal). The typical AM band, 550 to 1600 KHz, would allow about 5 stations only for a given area. But it gets more complicated then that..... FM has the "Capture Effect"- The ability for a stronger signal of two (or more) signals to be demodulated and make the weaker signal even more weaker, hence blocking it out. (Which is pretty handy if you live next to a tower with a lot of FM broadcast stations, and only want to pick up one. Also helps with noise.) But with Frequencies down on the AM broadcast band, wavelengths travel extremely long distances, mostly during the day. (But there can be some anomalies during the day) So stations would be mixing and capturing each other, pretty much resulting in 5 stations per perhaps 500 miles. Even stations out side the 500 mile zone could mix, providing conditions of the atmosphere is right. ..........Sorry for the long reply, It's a good thought. I'd love to listen to stations way off in other states crystal clear with no lightning crash or other electrical interference.
If someone wants to make one themselves quickly, there is this IC called PAM8304, a 2x3W amplifier, 3W might sound like low power, but when you attach it to bookshelf speakers you will be surprised at how loud it can get!
The explanation of Class D amplifier is excellent. I have built Class A, B and C amplifier in the past. I own several cheap Class D amplifier today. This video explains clearly of the theory of operations. You have excellent soldering skill as well. Keep up the good work!
Ive DIYed hundreds of speakers but never an amp. Definitely on my bucket list. I like how you use hand diagrams. I sense you know what you're talking about; something that can be lacking on youtube from time to time :)
This is the first time I am listening for type D audio amplifier. I appreciate your way of explaining the circuit and components. Please more circuits. Thanks
Great video Scott, may I request a video explaining how to read and apply characteristic curves/graphs and technical table spec sheets of semiconductor devices such as transistors and diodes to constructing circuits? Because I got confused in some parts of the video wherein you made use of those curves and tables but I didn't understand why those values mattered and how to interpret them in the way you did. Also, may I suggest when displaying those curves/graphs to not show them at a dutch angle? It seems a bit difficult to interpret at first viewing. Thank you for all these very technical but non-jargon heavy electronics videos, they're quite insightful. Hope to hear more from you Scott.
Another great video!!! My brain started to bleed about 15 seconds into when you were doing the calculation for the LC filter. I went back over that part about 10 times till I understood it " Yea Right" Thanks again for all you do.
This design could benefit from some overall negative feedback to help with the non-linearity. An integrator to generator a proper triangular waveform from the 555 would also be an improvement.
Mate, I studied micro electronics way back in the 80s, JK Flip flops, MUX and DEMUX, even how to program in 4 and 8 bit. You lost me in the first minute, I’m feeling old!! All that said, I can follow what you are saying, thank you so much for the fort.
first DIY where everything, even with calculations, is explained...usually, they just tell you to connect the components and turn the power on...great job, man!
Great scott! I have a couple of questions: 1. What if I apply a square or triangle wave to the input of a transformer instead of a sine wave? 2. Will you make a tutorial about electromagnetic levitation? 3. Where can I buy a transformer like that which u used in the pain test video?
Thomas 131377 It will work, but the voltage at the secondary will not be exactly as same as that on the primary. A square wave is basically sum of infinite number of sine and cosine waves of different amplitudes and frequencies multiple of the fundamental frequency ( According to fourier series). Transformer coil is inductive and the reactance is different for different "harmonics". So the output will be of same frequency as that of the square wave but a little distorted.
Thomas 131377 i want to know how do i match a speaker to an amp? speakers come in various ohms, wattage and sizes. if an amp has 100w 8ohm output then can I choose a 200w 8ohm speaker or I can use 80w 8ohm speaker also? how do I know what size (diameter) of a speaker will work?
Not really. If even the energy cannot be elliminated, the heat produced by the transistors are useless and even harmful. And that is why we use heat sinks.
I was just looking around for a well-explained D-Class amp, and thought I'd never find one. Then I get a notification and GS has come to save the day again. Well done :D
Thanks for sharing your expert advice and advanced expensive equipment to validate the authenticity of your video. I appreciate a true hobbyist that does these things cause he can. I think its awesome how your showing the signal from the original pre amp to the fully amplified filtered signal (sound). I am glad you included your specs on the components. I can finally move forward with my similar project with confidence of proper sizing of my components and correct IC's. I only get one shot at this because I am not able to buy materials. You have just made my day four years ago today. I never researched this topic on RUclips before but I am thankful I ran across yours. Its been a long few days sorting through all the fake non-proven videos. I harvest my materials from broken electronics people put in the trash. That is very easy. The hard part is the research. I do not have the equipment to achieve the perfect results I insist from myself. Cheers I appreciate all the time, effort, skill, and money you put into this truly educational video. Perfect!!!!Thanks
I love class D amps, I have a 300W PA from Yamaha based on a class D, it is wonderful. For those in the comments saying "no point you can buy it for cheap blah blah" the point is you learn something! you can then design and build your own amps to your own specifications, repair malfunctioning ones and get a better overall knowledge of electronics. Just buying it teaches you nothing.
Nice video! I had a question about the design though. Since this is a single-supply class D amp, what does the low-side switch do? When the high-side is on, the voltage potential is VCC to ground, but low side just connects the speakers ground to the MOSFET ground instead of to a negative supply. Did I miss something?
The low side MOSFET discharges the capacitor when the resulting signal is going through a negative slope, particularly when this slope is steep, it's easy to be deceived into thinking current through L only flows in one direction, but that's not the case, as C can be discharged through L and through low side MOSFET to ground, quickly lowering output voltage.
I just received this exact kit! Came with all the components, the LCD, test probe and even a clear acrylic case and screws... the PCB is even the same! I'm looking forward to building it and hope I can get some good results. BTW the specs state it is only good up to 200kHz, which is fine for what I need.
Question: Why did you omit the DC blocking capacitor to the output? The coil does not block DC and feeding DC to speakers reduces its performance and durability. You said it wasn't perfect and i get that, but it's just another cap maybe a 1000uF 25V, not much effort since you are not using a negative supply. I might be wrong though, mainly asking just to clarify that :D
2 other to-220 is regulator for 5 and 12v. There should be 7.5v DC in output (14W for speaker) because output circuit is same as in switching dc regulators (like in motherboards).
Why would you want to see old tube technology? Semiconductors are so much easier to implement and use much less power. The only time a tube would be warranted is in very high power RF applications and even then semi's are quite good at this these days. An audio tube amp may use tubes for linearity but MOSFET's and BJT's are pretty good these days as well. Modern BJT's in class A mode can sound just like tubes in audio applications.
Because it's cool learning how stuff works Shane. How about a Nixie tube clock? This guy relearned how to make Nixie tubes: www.daliborfarny.com/ , his are still quite expensive apparently but maybe he'll get you some cheaply for some publicity?
Hi Scott, great video. very educational. And I love this done with discrete components. I heard you said the amplifier was far from perfect. I know this is for learning but could you mention the missing things that could be improoved? Looking forward to learn more. Maybe I should get a book on class D amplifiers as I do for class AB.
Suggested improvement to reduce distortion: add transistor diode current source instead of the resistance between pin 7 and vcc of the 555 to linearize the triangle wave
A class D amp is analogous to a SMPS vs a conventional supply being much more efficient. Class A are around only 20-50%, B's 75%. D seems perfect for audio applications, good video.
On every sunday, I am waiting for your video at this time, very exited to see the topic of the video , after all , I watch the video and comment like this . like if the same happens with you
Hahaha ..... I love your soldering technique!!! Very nicely done to which I will state that you have alot of patients in your soldering method for sure.
I remember when back in the day I had to draw circuits for college, they always worked as intended but those diagrams looked hideous...but damn are his diagrams pretty or what? just look at them they look printed.
It’s like a hidden rule you either draw well but can’t build shit or too ur schematics look beautiful, but you can’t make it worth a shit. He is an exception
I made my own filterless class D amplifier just with Arduino. No filter, just plug in the speaker directly to the I/O pin then it works. It still requires biasing circuit and preamp. The key is the direct modification of PWM registry and some brute computation.
Thank you nice video and very informative. You have given us the basic block diagram and principal of class D amplification. I always did wonder how they derived that high-frequency PWM signal. Seems so simple now I see it here! :)
Practical class d amps do not use open loop pwm. They use self oscillating closed loop modulation that create a variable frequency pwm. Latest gen class d operate at around 750kHz av frequency.
When you are a bit confused so you rewatch 10 Times but still dont really know You know what i buy a amplifier on ebay bcuz im confused And make the equalizer circuit myself
You are a genius Pal, the way you've designed the circuit and the way you've explained the circuit and it's working, moreover the circuit you've drawn are simply awesome and easily understandable. Your handwriting was the best I've ever seen and your presentation was so good that it made us to concentrate on what we have to. Thumsup for you✌❤❤
I think you could try emitter degeneration on your amps/comparators, as your descrete transistors arent well matched as they would be on IC's. :) in bias current outputs, the Vce is larger, so they get hotter and lower threshold, so current increases even more until your operating point is way off. Love the look of that PCB! 👏
You should show us how to make high and low pass filters to make both active and passive crossover networks and essentially our own sound system. Between the amplifiers, the sound system, and videos of making LED's flash to the bass, I feel like a really cool project could be created.
This reminds me when I was on the 8th grade or something and I used an amplifier board from some old computer speakers and converted it for powering my headphones. That being said, I had the loudest headphones of the entire school 😆😆
I've got a video suggestion for you; make an active noise cancelling circuit that you can plug your sound source and headphones to and get a silent noise free listening experience!
Nice build. ...Killing me by using the 386 on a class D, but I've done the same before. They make convenient buffers. If you want a warmer vintage sound (the LM386 is adding it's own tone so you might as well choose a style), check out the site runoffgroove.com (no affiliation). Their open source "Fetzer Valve Deluxe" project goes through how to create a single JFET buffer that sounds really interesting. I have that stage running in front of 2 different guitar amps and I like it. It would be interesting to see how a 'tube amp' simulated circuit sounds with a "Class D" output.
I really like your videos. But the thing is, ok now i have the necessary information to potentially make this myself but i feel like i could never come up with the circuit myself. A video where you explain your way of going at it from scratch would be amazing. I feel like thats the best way to learn something.
Haven't seen an Class D amplifier done discrete till now. You did an great build. If im not mistaken, feedback can be used for the Class D amplifier to linearize the output more.
Excellent engineering and testing. I need a two channel or stereo version for a tv headphone signal driving a pair of amplified pc speakers. Thank you for your encouraging videos.
This is a really interesting design since it eliminates the need for dual rail supply. Most of the designs I've seen need a separate converter (or supply) for dual rail voltages.
I love anything to do with amplification.... Awesome video and keep up with the good work... I would love to see videos on class A and class A/B amplification.
Before an audio signal is amplified it gets DC biased to half the supply voltage (a.k.a virtual ground) to amplify the negative half wave of the audio output without clipping, so the output is nonetheless a DC biased audio output. You need a 1000uF decoupling capacitor to remove all that bias before interfacing the speaker..well unless you're amplifying with a negative supply rail, at least.
That's exactly what i needed, now by modifying the schematics i can make my own 600W sub-woofer amp. And maybe for the next project you can build super simple AM transmitter using TXCO for example... Or DIY UPS unit... Thanks a lot Scott! i'm waiting for next project :}
The math that you used to create your output filter was very informative. However, if you try turning the music down, you will hear zero crossing distortion. This is because it is necessary to create a dead time to allow one transistor to turn off before allowing the other to switch on. The higher the clock speed, the more apparent the zero crossing becomes. When playing loud, it's more than 20 db below the peak, so it is drowned out, and sounds pretty good. You can't beat the efficiency though. This topology maintains good efficiency at any load, any amplitude. The same cannot be said for a linear output stage. If you do a hysteresis feed back topology, and do away with the triangle wave generator, you will have pulse by pulse feedback, eliminating any trace of zero crossing distortion. You will greatly improve signal to noise ratio, and greatly simplify the circuit. I wish I had a way to show you a basic schematic to try.
I honestly love your diagrams, ur handwriting and diagrams are so neat!
I know, I'd love to see him make a draw my life! Just for the diagrams :D
Connor Edwards - Music "Draw My Life"
*Draws Buck-Boost converter circuit diagram*
Mayank Jain Gay!
honestly, whenever he writes ones, they look like lambdas(greek), which makes it especially confusing when he refers to wave functions.
@@froople Hahahahaha!
I have followed this video to build a class D amp. There's some thing you should know if you also want to follow this video.
the 1nf capacitor at 555 timer is used to convert square wave into triangle wave. In my case 1nf is to small to fully convert the square wave, you should hook up a oscilloscope and swap a few different capacitor until you see triangle wave.
R3 (2k ohm) is used to control the frequency at which 555 timer oscillate. I'm not using TLC555, instead I use NE555, in which case the frequency is only 2k Hz if I use 2k ohm resistor for R3. To solve this, you simply replace R3 with a 10k potentiometer, and see what resistance is required to get 200k Hz.
I added a 1000uF capacitor in series with the speaker as a coupling capacitor to block the dc at output stage.
Any way, thank you @GreatScott! for making all the awesome videos about electrical stuff. It helped me a lot. Keep on
I must congratulate you. I have an electronics degree, and appreciated the way you explained the theory behind every step you took.
For sure I feel the same sir. I wrote a essay to compliment him. I appreciate people like you. I enjoy electronics so much its more than a hobby. I consumes me. People ask why I do not buy this stuff and I just cant. Although, I cant because I enjoy making it myself. I will spend 4 hours to make a $5 device. I am glad you complimented this gentleman in this video.
@@retrorocketman6969 No freaking way. You just described me to a T. I take everything apart and salvage hardware, fasteners, heat sinks, transistors etc. I needed a magnetic heated stir plate so I built one. I built the amplifier and sub in my van. I think anybody could buy one. Not too many can make one. I have a 22 year old zero turn mower that runs circles around new ones. I feel good about repurposing junk. It is more than a hobby. Kind of an obsession. I'll fall in my own coffin with a file in one hand and a soldering iron in the other. 😁
must not be a very useful degree if you are watching this 😂
@@nobytes2 I'm sorry your degree compels you put down people to feel funny. Have a wonderful week.
@@hectorguevara6069I mean he's not completely wrong
I dont know why i'm here, but i didn't skip every single seconds till the end. This is why YT should exist.
Great work!
You don't happen to have an old set of cabinet speakers lying around, do you? It's amazing how much an enclosure can increase the sound output of a speaker.
@Nash Finnley This is a bot.
i guess Im asking the wrong place but does anybody know of a way to get back into an instagram account?
I somehow lost my password. I would appreciate any tricks you can give me
@River Immanuel instablaster :)
@Anakin Rudy thanks so much for your reply. I found the site thru google and im waiting for the hacking stuff now.
Seems to take quite some time so I will reply here later with my results.
@Anakin Rudy It did the trick and I now got access to my account again. Im so happy:D
Thank you so much you really help me out :D
Hey Scott, make a long range radio transmitter and receiver, and maybe show us how to calculate its range. That'd be fantastic!
yeh, if could u make transmitter and receiver circuit for like something that is rc that'd be fantastic
It would be really awesome if it can achieve really high LOS ranges.
I don't think he wants to do that since it's illegal here in Germany. But it's very simple and many videos are online for that.
The reason there is no FM on Shortwave ( Or AM and LW) is because the band width is not there that is required. Broadcast FM takes up nearly 200 Khz of "bandwidth" (Which also accounts for Guard bands, frequency deviation of the transmitter, and the bandwidth of signal). The typical AM band, 550 to 1600 KHz, would allow about 5 stations only for a given area. But it gets more complicated then that..... FM has the "Capture Effect"- The ability for a stronger signal of two (or more) signals to be demodulated and make the weaker signal even more weaker, hence blocking it out. (Which is pretty handy if you live next to a tower with a lot of FM broadcast stations, and only want to pick up one. Also helps with noise.) But with Frequencies down on the AM broadcast band, wavelengths travel extremely long distances, mostly during the day. (But there can be some anomalies during the day) So stations would be mixing and capturing each other, pretty much resulting in 5 stations per perhaps 500 miles. Even stations out side the 500 mile zone could mix, providing conditions of the atmosphere is right. ..........Sorry for the long reply, It's a good thought. I'd love to listen to stations way off in other states crystal clear with no lightning crash or other electrical interference.
At 11 and 10m you are allowed to transmit in FM and or AM.
I wish I knew what you were talking about, but I love watching a knowledgeable person work.
This is the best way to visually describe what's going on during the process. Awesome video. Phenomenal way of teaching.
If someone wants to make one themselves quickly, there is this IC called PAM8304, a 2x3W amplifier, 3W might sound like low power, but when you attach it to bookshelf speakers you will be surprised at how loud it can get!
This is the ultimate "what I had lying around" build. Love the parallel capacitors. The end product looks retro i like it!
I simply love the way he drew everything so neatly, so pleasing to watch that I could watching it all day! =D
The explanation of Class D amplifier is excellent. I have built Class A, B and C amplifier in the past. I own several cheap Class D amplifier today. This video explains clearly of the theory of operations. You have excellent soldering skill as well. Keep up the good work!
I love seeing those Manhattan circuits! So beautiful!
Ive DIYed hundreds of speakers but never an amp. Definitely on my bucket list. I like how you use hand diagrams. I sense you know what you're talking about; something that can be lacking on youtube from time to time :)
I know you look upto Afrotechmods, but your tutorial squashes his one by far🙌😁
This is the first time I am listening for type D audio amplifier. I appreciate your way of explaining the circuit and components. Please more circuits. Thanks
I'm here for the glorious drawing and handwriting!
The 'i'll see you next time' at the end is so calm it relieves all my stress and anxiety
Great video Scott, may I request a video explaining how to read and apply characteristic curves/graphs and technical table spec sheets of semiconductor devices such as transistors and diodes to constructing circuits? Because I got confused in some parts of the video wherein you made use of those curves and tables but I didn't understand why those values mattered and how to interpret them in the way you did. Also, may I suggest when displaying those curves/graphs to not show them at a dutch angle? It seems a bit difficult to interpret at first viewing. Thank you for all these very technical but non-jargon heavy electronics videos, they're quite insightful. Hope to hear more from you Scott.
Another great video!!! My brain started to bleed about 15 seconds into when you were doing the calculation for the LC filter. I went back over that part about 10 times till I understood it " Yea Right"
Thanks again for all you do.
This design could benefit from some overall negative feedback to help with the non-linearity. An integrator to generator a proper triangular waveform from the 555 would also be an improvement.
Mate, I studied micro electronics way back in the 80s, JK Flip flops, MUX and DEMUX, even how to program in 4 and 8 bit. You lost me in the first minute, I’m feeling old!! All that said, I can follow what you are saying, thank you so much for the fort.
I barely understand any of this, but this is gold
Me too. But still watch
first DIY where everything, even with calculations, is explained...usually, they just tell you to connect the components and turn the power on...great job, man!
great explanation! I love the detail of the circuit layout and values. Good job. we need more audio circuitry here on RUclips.
I am amazed at your organization on your circuit boards. It requires so much precision.
Great scott! I have a couple of questions:
1. What if I apply a square or triangle wave to the input of a transformer instead of a sine wave?
2. Will you make a tutorial about electromagnetic levitation?
3. Where can I buy a transformer like that which u used in the pain test video?
1. Works similar but has a couple of negative side effects. Better ask Google.
2. Sure.
3. Ebay
GreatScott! Thank you for your answers!
Thomas 131377 It will work, but the voltage at the secondary will not be exactly as same as that on the primary. A square wave is basically sum of infinite number of sine and cosine waves of different amplitudes and frequencies multiple of the fundamental frequency ( According to fourier series). Transformer coil is inductive and the reactance is different for different "harmonics". So the output will be of same frequency as that of the square wave but a little distorted.
Thomas 131377 3) Look for a "variac" or Stelltrafo. But don't forget that these are not galvanically isolated.
Thomas 131377 i want to know how do i match a speaker to an amp? speakers come in various ohms, wattage and sizes. if an amp has 100w 8ohm output then can I choose a 200w 8ohm speaker or I can use 80w 8ohm speaker also? how do I know what size (diameter) of a speaker will work?
is awesome to be working on some audio circuits and receive a notification saying "class D amp" from great scott! made my day
Dont waste energy kids
Ahmet Asantas eh.
Ahmet Asantas you can't "waste" energy it can only be transferred from one store to another
Ahmet Asantas you can't "waste" energy it can only be transferred from one store to another. I listen in science (most of the time)
Not really. If even the energy cannot be elliminated, the heat produced by the transistors are useless and even harmful. And that is why we use heat sinks.
Well, the heat dissipated will keep you nice and warm during the winter?
I was just looking around for a well-explained D-Class amp, and thought I'd never find one. Then I get a notification and GS has come to save the day again. Well done :D
check out Afrotechmods D class amp tutorial
clicked, liked, viewing in progress
same :D
nobody gives a shit m8
+W0W You just did!
WoW
Rohit Datar you beat me at my own game
You lost me a little when you started getting deep into the circuit analysis, but i stayed for your satisfying drawings and graphs.
Great scott your awesome. Liked before watching i just lovee your videos
you're greatscott copyer😑
Let's just say I inspired him :-)
i know that you inspired him 🤗
Yes great scott your right you inspired me
He's eveng using your music on his videos...
Thanks for sharing your expert advice and advanced expensive equipment to validate the authenticity of your video. I appreciate a true hobbyist that does these things cause he can. I think its awesome how your showing the signal from the original pre amp to the fully amplified filtered signal (sound). I am glad you included your specs on the components. I can finally move forward with my similar project with confidence of proper sizing of my components and correct IC's. I only get one shot at this because I am not able to buy materials. You have just made my day four years ago today. I never researched this topic on RUclips before but I am thankful I ran across yours. Its been a long few days sorting through all the fake non-proven videos. I harvest my materials from broken electronics people put in the trash. That is very easy. The hard part is the research. I do not have the equipment to achieve the perfect results I insist from myself. Cheers I appreciate all the time, effort, skill, and money you put into this truly educational video. Perfect!!!!Thanks
i love your work and so i translated everything into french in the subtitle
I don't have a card and your channel makes me miss the local radio shack
A. video from great scott! ?? so, I can have a nice day definitely.
good work. thanks for your time and efforts. Love from INDIA.
Insanely polished videos .. I can't even imagine how much it must take to get these done .. Thanks !
When people listen to music ,I listen to his amp hour interview
He's not the host of the amp hour podcast.
Proto G he has been on AmpHour once
I know, but it's not his podcast.
I love class D amps, I have a 300W PA from Yamaha based on a class D, it is wonderful. For those in the comments saying "no point you can buy it for cheap blah blah" the point is you learn something! you can then design and build your own amps to your own specifications, repair malfunctioning ones and get a better overall knowledge of electronics. Just buying it teaches you nothing.
7:20
I would reduce the control voltage of the 555 and re-tune the DC offset
..and maybe use a speaker in a cabinet, or that one sat in a small enclosure
simply i want to kiss your hands because the neatness of your handwriting and schematics.......
Nice video! I had a question about the design though. Since this is a single-supply class D amp, what does the low-side switch do? When the high-side is on, the voltage potential is VCC to ground, but low side just connects the speakers ground to the MOSFET ground instead of to a negative supply. Did I miss something?
The low side MOSFET discharges the capacitor when the resulting signal is going through a negative slope, particularly when this slope is steep, it's easy to be deceived into thinking current through L only flows in one direction, but that's not the case, as C can be discharged through L and through low side MOSFET to ground, quickly lowering output voltage.
@@diego5733 so would the signal have a DC ofset?
I just received this exact kit! Came with all the components, the LCD, test probe and even a clear acrylic case and screws... the PCB is even the same! I'm looking forward to building it and hope I can get some good results. BTW the specs state it is only good up to 200kHz, which is fine for what I need.
I wish to learn everything you've done in this project From calculation to actual assembly of circuit but I lack in knowledge 😢
Thats what we do in electrical engineering, what he showed here is basically 2nd and 3rd semester stuff
I have not even started the video, and I already know I'm going to love it, and definitely build it. This is exciting.
Sweet.
Question: Why did you omit the DC blocking capacitor to the output? The coil does not block DC and feeding DC to speakers reduces its performance and durability. You said it wasn't perfect and i get that, but it's just another cap maybe a 1000uF 25V, not much effort since you are not using a negative supply. I might be wrong though, mainly asking just to clarify that :D
The board looks like its a bridge-tied load - 4 MOSFETs and 2 output inductors, so no DC-blocking needed.
2 other to-220 is regulator for 5 and 12v. There should be 7.5v DC in output (14W for speaker) because output circuit is same as in switching dc regulators (like in motherboards).
I just sat my GCSE systems (electronics) paper and you have had a huge impact on my understanding and revision. Thanks!
Make something abaut tubes ?
I put it on my to do list
дядя Kakadu and other obsolete tech. You could make a top 10 list or something.
Why would you want to see old tube technology? Semiconductors are so much easier to implement and use much less power. The only time a tube would be warranted is in very high power RF applications and even then semi's are quite good at this these days. An audio tube amp may use tubes for linearity but MOSFET's and BJT's are pretty good these days as well. Modern BJT's in class A mode can sound just like tubes in audio applications.
Because it's cool learning how stuff works Shane.
How about a Nixie tube clock? This guy relearned how to make Nixie tubes: www.daliborfarny.com/ , his are still quite expensive apparently but maybe he'll get you some cheaply for some publicity?
Alex C that's an acceptable answer.
in my 5 years in electronics engineering, they have never taught us the theory behind class d amps. thanks for explaining!
Its the same as the theory behind switch-mode power conversion.
Hi Scott, great video. very educational. And I love this done with discrete components. I heard you said the amplifier was far from perfect. I know this is for learning but could you mention the missing things that could be improoved? Looking forward to learn more. Maybe I should get a book on class D amplifiers as I do for class AB.
I love the look of your hand drawn schematics.They look very clean.
You should hang all of them in your workshop!
Suggested improvement to reduce distortion: add transistor diode current source instead of the resistance between pin 7 and vcc of the 555 to linearize the triangle wave
A class D amp is analogous to a SMPS vs a conventional supply being much more efficient. Class A are around only 20-50%, B's 75%. D seems perfect for audio applications, good video.
you must open a second channel named electronics porn...
but why are you saying that???
DEMONETIZED
I just gotta say, look how clean your schematics are
On every sunday, I am waiting for your video at this time, very exited to see the topic of the video , after all , I watch the video and comment like this . like if the same happens with you
Hahaha ..... I love your soldering technique!!! Very nicely done to which I will state that you have alot of patients in your soldering method for sure.
When she wants that class D
Your video is much much better then someone video said top circuit, free energy .. at least your circuit make sense and working.
I remember when back in the day I had to draw circuits for college, they always worked as intended but those diagrams looked hideous...but damn are his diagrams pretty or what? just look at them they look printed.
It’s like a hidden rule you either draw well but can’t build shit or too ur schematics look beautiful, but you can’t make it worth a shit. He is an exception
I made my own filterless class D amplifier just with Arduino. No filter, just plug in the speaker directly to the I/O pin then it works. It still requires biasing circuit and preamp. The key is the direct modification of PWM registry and some brute computation.
6:53 Hah! Now I know what tracks you use in your videos!
Thank you nice video and very informative. You have given us the basic block diagram and principal of class D amplification. I always did wonder how they derived that high-frequency PWM signal. Seems so simple now I see it here! :)
how many watts is the speaker
4V / 4ohms = 1W
Practical class d amps do not use open loop pwm. They use self oscillating closed loop modulation that create a variable frequency pwm. Latest gen class d operate at around 750kHz av frequency.
When you are a bit confused so you rewatch 10 Times but still dont really know
You know what i buy a amplifier on ebay bcuz im confused
And make the equalizer circuit myself
Have you tried not being an idiot? I hear that helps...
@@aakksshhaayy well yes but Actully no
@@Rainbow__cookie lel just kidding around. i'm the actual idiot
¡Naahhh, este Scott es una cornucopia de conocimiento!!
This Scott is a cornucopia of knowledge!!
What kind of pen do you use?
Stabilo Point 88
I would really like to see you build a remote controlled car. My kids would be so impressed! Awesome video btw 👍🏻
can you do a tutorial on how to make a diy microphone circuit
Sure
You are a genius Pal, the way you've designed the circuit and the way you've explained the circuit and it's working, moreover the circuit you've drawn are simply awesome and easily understandable. Your handwriting was the best I've ever seen and your presentation was so good that it made us to concentrate on what we have to. Thumsup for you✌❤❤
Not bad for a southpaw. His artwork is so good too.
Dude honestly frap yourself :D.
Just when I was thinking "he should do a Class D amp video" you upload one in the next 2 hours.
You're left handed! Subbed for the content, but seeing a fellow leftie makes it even better ;)
last time I was that early there was no amplifier
I think you could try emitter degeneration on your amps/comparators, as your descrete transistors arent well matched as they would be on IC's. :) in bias current outputs, the Vce is larger, so they get hotter and lower threshold, so current increases even more until your operating point is way off.
Love the look of that PCB! 👏
@GreatScott @4:44
3dB point is 50%; not 30%.
Justin Davidow, i hoped that im not the only one who noticed that
-3dB is 50% of power. -6dB is 50% of amplitude.
You should show us how to make high and low pass filters to make both active and passive crossover networks and essentially our own sound system. Between the amplifiers, the sound system, and videos of making LED's flash to the bass, I feel like a really cool project could be created.
three downvotes after 3 minutes....wow
This reminds me when I was on the 8th grade or something and I used an amplifier board from some old computer speakers and converted it for powering my headphones. That being said, I had the loudest headphones of the entire school 😆😆
Nice Video.Please upload more often :)
Not possible
GreatScott! Why
You think such videos take only a couple of hours to produce?
GreatScott! I'm sorry for asking but I have one last question. Where is electronic basic's temperature measurement part 2?
GreatScott! Your upload rate is good and your videos professional. I would not like to see less professional videos.
I've got a video suggestion for you; make an active noise cancelling circuit that you can plug your sound source and headphones to and get a silent noise free listening experience!
Nice build. ...Killing me by using the 386 on a class D, but I've done the same before. They make convenient buffers.
If you want a warmer vintage sound (the LM386 is adding it's own tone so you might as well choose a style), check out the site runoffgroove.com (no affiliation). Their open source "Fetzer Valve Deluxe" project goes through how to create a single JFET buffer that sounds really interesting. I have that stage running in front of 2 different guitar amps and I like it. It would be interesting to see how a 'tube amp' simulated circuit sounds with a "Class D" output.
runoffgroove.com/fetzervalve.html
how he added 386 to the circuit?
and why? you can use 386 alone, without class D amp, so what the case? Is it in the quality of sound?
LM386 was used as a preamp, before the Class D.
I really like your videos. But the thing is, ok now i have the necessary information to potentially make this myself but i feel like i could never come up with the circuit myself. A video where you explain your way of going at it from scratch would be amazing. I feel like thats the best way to learn something.
There is no ground this is single supply and no full bridge amp so how it's low side working
Haven't seen an Class D amplifier done discrete till now. You did an great build.
If im not mistaken, feedback can be used for the Class D amplifier to linearize the output more.
Yes, feedback would have been the next step. But this was enough for one video.
i'm early, let me tell a joke.
Katy Perry
Music sounds so good through a home made stereo, no matter how bad it sounds in reality
This guy has an accent; he cannot be trusted
I don’t trust “Mehdi” telling me who does have an accent and
who doesn’t!
He is German. #MadeinGermany
is insulting necessary?
Excellent engineering and testing. I need a two channel or stereo version for a tv headphone signal driving a pair of amplified pc speakers.
Thank you for your encouraging videos.
Not worth it to make one you can buy amp board fore $1 15*2w sory grama
Important the destination is not. Quest for knowledge! :D
MP Dope but what if it is sold out and you have to build it?
go find a difrent channel we are here to bild and learn for fun not for the final product
Yes, but then you have to wait at least 1 week for it to arrive! What if you need it for this week?
What the fuck are you saying
The Video we all have been waiting for has come now!
those amplifiers are cheap so there is no point of making them yourself
If you apply this logic to everything in your electronics studies you will not learn anything new.
That´s right.
GreatScott! I couldn't agree more
GreatScott! that's true
I came all the way from Twitter just to like this
Good job Scott !! Im happy to do those circuitswith this level of instruction !! Ty so much !
This is a really interesting design since it eliminates the need for dual rail supply. Most of the designs I've seen need a separate converter (or supply) for dual rail voltages.
There are many designs out there that work off a single supply...
"dont forget to like share and sub, stay creative and i will see u next time" love these lines sooooooooooooooo much
I love anything to do with amplification.... Awesome video and keep up with the good work... I would love to see videos on class A and class A/B amplification.
Before an audio signal is amplified it gets DC biased to half the supply voltage (a.k.a virtual ground) to amplify the negative half wave of the audio output without clipping, so the output is nonetheless a DC biased audio output. You need a 1000uF decoupling capacitor to remove all that bias before interfacing the speaker..well unless you're amplifying with a negative supply rail, at least.
That's exactly what i needed, now by modifying the schematics i can make my own 600W sub-woofer amp.
And maybe for the next project you can build super simple AM transmitter using TXCO for example...
Or DIY UPS unit... Thanks a lot Scott! i'm waiting for next project :}
The math that you used to create your output filter was very informative. However, if you try turning the music down, you will hear zero crossing distortion. This is because it is necessary to create a dead time to allow one transistor to turn off before allowing the other to switch on. The higher the clock speed, the more apparent the zero crossing becomes. When playing loud, it's more than 20 db below the peak, so it is drowned out, and sounds pretty good. You can't beat the efficiency though. This topology maintains good efficiency at any load, any amplitude. The same cannot be said for a linear output stage. If you do a hysteresis feed back topology, and do away with the triangle wave generator, you will have pulse by pulse feedback, eliminating any trace of zero crossing distortion. You will greatly improve signal to noise ratio, and greatly simplify the circuit. I wish I had a way to show you a basic schematic to try.