DIY Class D Audio Amplifier

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Amplifier circuit file on EasyEDA: easyeda.com/GreatScott/ClassD...
Support me for more videos: / greatscott
Previous video: • TEVO Little Monster 3D...
Class AB Audio Amp video: • Make your own Low Budg...
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More project information (schematic pictures,....) on Instructables: www.instructables.com/id/DIY-...
Thanks to EasyEDA for sponsoring this video.
Free circuit design tool with 200,000 users: easyeda.com
$2 for10pcs 2-layer 10x10cm PCB prototype here: easyeda.com/order
Wide selection in-stock components: lcsc.com
Parts list (Incomplete, see Instructables for Ebay and Amazon.de, affiliate links):
Aliexpress:
1x 3.5mm Audio Jack: s.click.aliexpress.com/e/_dYy...
1x 10kΩ Potentiometer: s.click.aliexpress.com/e/_dX8...
1x LM393 Comparator: s.click.aliexpress.com/e/_d7O...
1x TLC555 Timer: s.click.aliexpress.com/e/_dTr...
1x 74HC04 Inverter: s.click.aliexpress.com/e/_d8c...
1x IR2113 MOSFET Driver: s.click.aliexpress.com/e/_d7S...
2x IRLZ44N MOSFET: s.click.aliexpress.com/e/_dWh...
1x 7805 Voltage Regulator: s.click.aliexpress.com/e/_dXS...
1x 7812 Voltage Regulator: s.click.aliexpress.com/e/_d8O...
2x PCB Terminal: s.click.aliexpress.com/e/_dYb...
3x 47µF, 1x 22µF Capacitor: s.click.aliexpress.com/e/_d7d...
7x 220nF Capacitor: s.click.aliexpress.com/e/_dU4...
3x UF4007 Diode: s.click.aliexpress.com/e/_dYR...
2x 10kΩ, 2x 10Ω, 1x 2kΩ Resistor: s.click.aliexpress.com/e/_dTP...
2x 33µH Inductor: s.click.aliexpress.com/e/_d6A...
In this project I will show you why a class AB amplifier is pretty inefficient and how a class D amplifier on the other hand improves this efficiency. At the end I will show you how we can apply the theory of operation of a class D amp to a couple of common components in order to create our own DIY class D audio amp.
Music:
2011 Lookalike by Bartlebeats
Killing Time, Kevin MacLeod (incompetech.com)

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3 июл 2024

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Комментарии : 924

@MayankJaintheswag101 7 лет назад

I honestly love your diagrams, ur handwriting and diagrams are so neat!

@froople 7 лет назад

I know, I'd love to see him make a draw my life! Just for the diagrams :D

@ciarfah 7 лет назад

Connor Edwards - Music "Draw My Life" *Draws Buck-Boost converter circuit diagram*

@gene_Code 6 лет назад

Mayank Jain Gay!

@Batman-od9zv 5 лет назад

honestly, whenever he writes ones, they look like lambdas(greek), which makes it especially confusing when he refers to wave functions.

@eltonjam 5 лет назад

@@froople Hahahahaha!

@user-go6kw3ye3u Год назад

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

@invidios 5 лет назад

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!

@rontan8433 4 года назад

I simply love the way he drew everything so neatly, so pleasing to watch that I could watching it all day! =D

@hectorguevara6069 5 лет назад

I must congratulate you. I have an electronics degree, and appreciated the way you explained the theory behind every step you took.

@retrorocketman6969 2 года назад

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.

@2pist Год назад

@@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. 😁

@nobytes2 10 месяцев назад

must not be a very useful degree if you are watching this 😂

@hectorguevara6069 10 месяцев назад

@@nobytes2 I'm sorry your degree compels you put down people to feel funny. Have a wonderful week.

@misperry 7 лет назад

great explanation! I love the detail of the circuit layout and values. Good job. we need more audio circuitry here on RU-vid.

@DullPoints 5 лет назад

I wish I knew what you were talking about, but I love watching a knowledgeable person work.

@tobywenman4769 7 лет назад

I just sat my GCSE systems (electronics) paper and you have had a huge impact on my understanding and revision. Thanks!

@zdw306 3 года назад

I love seeing those Manhattan circuits! So beautiful!

@MichaelOfRohan 2 года назад

This is the ultimate "what I had lying around" build. Love the parallel capacitors. The end product looks retro i like it!

@willwahlberg1890 2 года назад

I am amazed at your organization on your circuit boards. It requires so much precision.

@barbasbandas6665 7 лет назад

is awesome to be working on some audio circuits and receive a notification saying "class D amp" from great scott! made my day

@zaldstudio 6 лет назад

I'm here for the glorious drawing and handwriting!

@LazerLord10 7 лет назад

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.

@McMasterProGenius 3 года назад

@Nash Finnley This is a bot.

@riverimmanuel7955 2 года назад

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

@anakinrudy2027 2 года назад

@River Immanuel instablaster :)

@riverimmanuel7955 2 года назад

@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.

@riverimmanuel7955 2 года назад

@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

@Darieee 7 лет назад

Insanely polished videos .. I can't even imagine how much it must take to get these done .. Thanks !

@albertlee8537 7 лет назад

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!

@mohammedmokhtar 7 лет назад

Hey Scott, make a long range radio transmitter and receiver, and maybe show us how to calculate its range. That'd be fantastic!

@fireemittingtomato4122 7 лет назад

yeh, if could u make transmitter and receiver circuit for like something that is rc that'd be fantastic

@mohammedmokhtar 7 лет назад

It would be really awesome if it can achieve really high LOS ranges.

@LeLyfa 7 лет назад

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.

@JDtheEE 7 лет назад

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.

@LeLyfa 7 лет назад

At 11 and 10m you are allowed to transmit in FM and or AM.

@marcbarbier5646 5 лет назад

i love your work and so i translated everything into french in the subtitle

@jitsinghobhi Год назад

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

@BADALICE 4 года назад

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.

@MrTrollicus 7 лет назад

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!

@aldwinvicente3490 7 лет назад

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.

@ImpulseAudioSpeakers 7 лет назад

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 :)

@fewr.x 7 лет назад

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

@maks886 7 лет назад

check out Afrotechmods D class amp tutorial

@kaumohlamonyane272 7 лет назад

I know you look upto Afrotechmods, but your tutorial squashes his one by far🙌😁

@ferrumignis 5 лет назад

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.

@adityag.5372 3 года назад

The 'i'll see you next time' at the end is so calm it relieves all my stress and anxiety

@keithmeyers3718 2 года назад

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.

@Aatikslab 7 лет назад

Great scott your awesome. Liked before watching i just lovee your videos

@julius4347 7 лет назад

you're greatscott copyer😑

@greatscottlab 7 лет назад

Let's just say I inspired him :-)

@julius4347 7 лет назад

i know that you inspired him 🤗

@Aatikslab 7 лет назад

Yes great scott your right you inspired me

@Marin0520 7 лет назад

He's eveng using your music on his videos...

@12KTOYOTA 4 года назад

I barely understand any of this, but this is gold

@Goch46 3 года назад

Me too. But still watch

@vahkiy 7 лет назад

Good job Scott !! Im happy to do those circuitswith this level of instruction !! Ty so much !

@ScienceEtConscience 7 лет назад

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!

@TradingFuturo 6 лет назад

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.

@TheJay6621 7 лет назад

A. video from great scott! ?? so, I can have a nice day definitely. good work. thanks for your time and efforts. Love from INDIA.

@denizadiguzel4766 7 лет назад

The Video we all have been waiting for has come now!

@spicymemeboi2646 7 лет назад

I love the look of your hand drawn schematics.They look very clean. You should hang all of them in your workshop!

@thewhitefalcon8539 7 лет назад

6:53 Hah! Now I know what tracks you use in your videos!

@shailendrapandit440 7 лет назад

When people listen to music ,I listen to his amp hour interview

@ProtoG42 7 лет назад

He's not the host of the amp hour podcast.

@FunScientifix 7 лет назад

Proto G he has been on AmpHour once

@ProtoG42 7 лет назад

I know, but it's not his podcast.

@artvnl6345 7 лет назад

wow I can't even draw so perfect on my pc, keep up these awsome video's!

@packratswhatif.3990 6 лет назад

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.

@Xyz-77 7 лет назад

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?

@greatscottlab 7 лет назад

1. Works similar but has a couple of negative side effects. Better ask Google. 2. Sure. 3. Ebay

@Xyz-77 7 лет назад

GreatScott! Thank you for your answers!

@maheshbhat8714 7 лет назад

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.

@RaivooCH 7 лет назад

Thomas 131377 3) Look for a "variac" or Stelltrafo. But don't forget that these are not galvanically isolated.

@debojitacharjee 7 лет назад

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?

@Haselui 7 лет назад

clicked, liked, viewing in progress

@rohitdatar3988 7 лет назад

same :D

@w0wguy 7 лет назад

nobody gives a shit m8

@rohitdatar3988 7 лет назад

+W0W You just did!

@chinchinox 7 лет назад

WoW

@w0wguy 7 лет назад

Rohit Datar you beat me at my own game

@kramer26 6 лет назад

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.

@RafelioPsi 7 лет назад

This is my favourite by far. Nice man.

@shamimsk4738 4 года назад

I wish to learn everything you've done in this project From calculation to actual assembly of circuit but I lack in knowledge 😢

@N00B283 3 года назад

Thats what we do in electrical engineering, what he showed here is basically 2nd and 3rd semester stuff

@shailendrapandit440 7 лет назад

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

@gmcjetpilot 5 лет назад

That really helped me understand the class D amp... nice work thanks

@sonodrome 5 лет назад

Excellent video, really clear and well presented. Bravo!

@ucmetoo1 7 лет назад

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

@tctrainconstruct2592 5 лет назад

7:20 I would reduce the control voltage of the 555 and re-tune the DC offset

@johnc3403 4 года назад

..and maybe use a speaker in a cabinet, or that one sat in a small enclosure

@youssefshmaysani3810 5 лет назад

instantly subscribed to this quality, great work well done !!

@electroumit 7 лет назад

Thank you. Your drawing and talking are great.

@ahmetasantas7099 7 лет назад

Dont waste energy kids

@Clide0_0 7 лет назад

Ahmet Asantas eh.

@baylee3754 7 лет назад

Ahmet Asantas you can't "waste" energy it can only be transferred from one store to another

@baylee3754 7 лет назад

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)

@tunahankaratay1523 7 лет назад

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.

@fuazexfuaze5484 6 лет назад

Well, the heat dissipated will keep you nice and warm during the winter?

@user-ed7gm7ol8k 7 лет назад

you must open a second channel named electronics porn...

@savvaspoulos9616 4 года назад

but why are you saying that???

@johnrubensaragi4125 4 года назад

DEMONETIZED

@CharlesAugustosc 7 лет назад

Very crazy! Sensational! Most Class d power amplifier please! thank You my friend! Brazil!!!

@michaeljakob8093 5 лет назад

Nice video! Very easy explained, and nice hand-drawings, cool!

@RapiBurrito 7 лет назад

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

@MarkTillotson 6 лет назад

The board looks like its a bridge-tied load - 4 MOSFETs and 2 output inductors, so no DC-blocking needed.

@LimbaZero 5 лет назад

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).

@mattnesterenko5596 5 лет назад

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?

@diego5733 5 лет назад

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.

@f.a3202 4 года назад

@@diego5733 so would the signal have a DC ofset?

@6p1p 4 года назад

Your video is much much better then someone video said top circuit, free energy .. at least your circuit make sense and working.

@TheCarlos206 7 лет назад

Nice!! I will do it in hollydays!

@marco_evertus 7 лет назад

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.

@petrosrz8990 4 года назад

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

@1999colebug 7 лет назад

What kind of pen do you use?

@greatscottlab 7 лет назад

Stabilo Point 88

@Shashikantjambagi 5 лет назад

I Really love your video making techniques and beautiful ckt diagrams

@marcusfred4480 4 года назад

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! :)

@fettagrabbar2648 7 лет назад

how many watts is the speaker

@JohnUsp 4 года назад

4V / 4ohms = 1W

@Rainbow__cookie 4 года назад

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

@aakksshhaayy 4 года назад

Have you tried not being an idiot? I hear that helps...

@Rainbow__cookie 4 года назад

@@aakksshhaayy well yes but Actully no

@aakksshhaayy 4 года назад

@@Rainbow__cookie lel just kidding around. i'm the actual idiot

@vidanatural_oficial 6 лет назад

thank you for the channel, I learn too much here.

@effectivesolutionsinc.3831 7 лет назад

Nice video. Always something new to learn!

@Maku254 7 лет назад

Make something abaut tubes ?

@greatscottlab 7 лет назад

I put it on my to do list

@kevinlivingston9563 7 лет назад

дядя Kakadu and other obsolete tech. You could make a top 10 list or something.

@shanemitchell5807 7 лет назад

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.

@thewhitefalcon8539 7 лет назад

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?

@kevinlivingston9563 7 лет назад

Alex C that's an acceptable answer.

@UpcycleElectronics 7 лет назад

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.

@UpcycleElectronics 7 лет назад

runoffgroove.com/fetzervalve.html

@octour 6 лет назад

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?

@jnevercast 5 лет назад

LM386 was used as a preamp, before the Class D.

@caiopereira1289 4 года назад

That opening song is a banger!

@talljjparis 7 лет назад

Another great Vid. Keep them coming and thanks!

@shawnlee2811 7 лет назад

Nice Video.Please upload more often :)

@greatscottlab 7 лет назад

Not possible

@shawnlee2811 7 лет назад

GreatScott! Why

@greatscottlab 7 лет назад

You think such videos take only a couple of hours to produce?

@shawnlee2811 7 лет назад

GreatScott! I'm sorry for asking but I have one last question. Where is electronic basic's temperature measurement part 2?

@ciprianciprian5228 7 лет назад

GreatScott! Your upload rate is good and your videos professional. I would not like to see less professional videos.

@yosifalasadi6207 7 лет назад

can you do a tutorial on how to make a diy microphone circuit

@greatscottlab 7 лет назад

Sure

@JOELwindows7 7 лет назад

Really Amazing simple Duper Awesome Awesome AWESOME AWESOME!!!

@victordavydov4987 7 лет назад

Need more video like this. thx

@mustardroshi418 7 лет назад

When she wants that class D

@CTiOmega 7 лет назад

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.

@tejagollagt 4 года назад

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✌❤❤

@2pist Год назад

Not bad for a southpaw. His artwork is so good too.

@IAmAmperes 7 лет назад

Loved it. Thank you! I'll subscribe right now!

@smoke4131 7 лет назад

last time I was that early there was no amplifier

@Electrondemon 5 лет назад

There is no ground this is single supply and no full bridge amp so how it's low side working

@waqasahmad5733 4 года назад

simply i want to kiss your hands because the neatness of your handwriting and schematics.......

@apurvsharma1261 7 лет назад

luv u great scott support from india :) keep it up mate

@Daniii438 7 лет назад

three downvotes after 3 minutes....wow

@JustinDavidow 7 лет назад

@GreatScott @4:44 3dB point is 50%; not 30%.

@HochFrequenzFreak 6 лет назад

Justin Davidow, i hoped that im not the only one who noticed that

@LimbaZero 5 лет назад

-3dB is 50% of power. -6dB is 50% of amplitude.

@Butters_Stunts 7 лет назад

I don't have a card and your channel makes me miss the local radio shack

@winniebenitez452 2 года назад

very nice knowledge bank you have created here...thanks.

@fdist04 7 лет назад

This guy has an accent; he cannot be trusted

@meisam9592 7 лет назад

I don’t trust “Mehdi” telling me who does have an accent and who doesn’t!

@realpufflebro 6 лет назад

He is German. #MadeinGermany

@areg7182 5 лет назад

is insulting necessary?

@pormestarierno228 7 лет назад

i'm early, let me tell a joke. Katy Perry

@PeterMilanovski 6 лет назад

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.