Great video! Very informative, thumbs up!

@KissAnalog

3 жыл бұрын

Thank you! I appreciate you!

Holy CRAP! I've never seen so many DMM's in one place before, haha! The way you describe this reminds me of how AM and FM works. - Pauly

@KissAnalog

3 жыл бұрын

Thanks Pauly;)

7:29 based on that tip alone i subbed. you're talking real lab talk and i like it.

@KissAnalog

3 жыл бұрын

That's fantastic! Glad to have you on the team;)

love this analysis

@KissAnalog

2 жыл бұрын

Thank you Hemantha!

this video is getting better with every second!! i really like this . its like i'm sitting with you on the bench. you're doing a really good job at explaining things! this is so helpful

@KissAnalog

3 жыл бұрын

I appreciate that! Thanks for your great feedback!

Great Job! YES I would love to see your scope images and more details about how the Comparator signals look and a closer look at the currents in the MOSFETS

@KissAnalog

11 ай бұрын

Thanks so much! I'm working on that video and should post that tomorrow - I hope;)

As a dealer tech, I know GM dealer parts. Wiring my son’s early 80’s car into the 21st century is my job. This led me to Mini ANL fuse distribution blocks for 3-4 circuits. After finding audiophiles discussing class-D amp and fuse sizing led me to you. Boy, that was long! They are actually taking output in watts, de-rating by 20%, dividing by system voltage at 13.8 volts and screw it up worse. We know P-I-E is the formula but a 1,400 watt amp divided by 0.8= 1,750 watts? What? Then divide system voltage 13.8Vdc, =128 amp fuse to protect the circuit. I have amp clamps, DMM and a lab scope but what am I missing? I truly think their abacus is a few beads shy of full. I have been an ASE Master Tech since 1978. I taught 6 electrical classes (Of 30) for ACDelco in 13 Midwest tech schools much less hold tech seminars for over 100 techs, owners and colleges instructors that were 4hrs long. Am I missing something here? Why use rated output of a “Class-D” amp instead of an amp clamp around supply voltage to pick a fuse for this 1 of 3 components. If they did it correctly, add all 3, then pick a main fuse next to the battery. Look, some techs won’t touch an automatic other than fluid & filter, but math used in electrical circuits, be it voltage drop, power solving or simple ohms law is not 100% accurate but real close. I really enjoy learning an watched twice. I can see there is a slight difference in time on the control side to out put. I don’t teach electronics at this level but I don’t like welding cable pinched in doors going into the trunk with a 300 amp fuse or none at all. I thought they were perhaps doing drive-by welding on mailboxes or exhaust. This is crazy. Thanks so much as you have many videos to watch that I want to know! Don’t retire because you have more work. DK, ASE master tech, 78. Retired.

@KissAnalog

Жыл бұрын

Wow impressive background! I appreciate any and all feedback. A current clamp at the input voltage supply cable would be a great way to measure the actual current at the input. Does the amplifier show input power requirements?

@deankay4434

Жыл бұрын

@@KissAnalog I don’t install stereos, amps or digital signal processors, but guys that do, produce these videos and admit that the amperage requirement on the box is probably wrong or missing. This proves my argument. Spend $45 or $90 and buy a nice amp clamp with a digital read out, then use it religiously. I do with with dielectric grease in plastic connectors over the terminals, but it won’t start a fire. Plus, who or what shady outfit sells audio equipment without specs like amperage requirement. At least they show best practices routing the cabling thru rubber grommets or factory locations but we all know some cut corners, speed up the install or just don’t care. A fuse is a temperature sensing device, not an amperage sensing device like some circuit with a Hall-effect switch using a shunt, pre-set to turn of an enhance high speed MOSFET to kill power. Temps are higher under the hood so giving them a 20% fudge is fine as long as you know the actual amperage. Cold inrush current is most likely never a problem like a starter. But todays starter have permanent magnets for the field with gear reduction. So while cranking, it maintains 90 amps +/- 10 amps on compression. But these pull 120 amps when you hit the key and drop. The alternator can produce 120 amps but in reality, it is closer to 110. So, off the battery into a pair of mini ANL fuses are fine at 150 amps. If a positive diode shorts to ground or the wire melts, same with the starter. My strategy is to run the starter & alternator thru a 150 amp ANL fuse, but because of his arrangement, I am using 6 ga wire to the alternator, then to distribution block the splits it 3 ways. Lights, 4-way emergency, brake, fuse box and ignition switch all need power constantly. His car will not need 150 amps, but to 50 amp fuses and one 30 operates everything he has. No big stereo, amp, A/C or blower fan. I amp building a vehicle (67 C10 PU) using computers from a 2003 Tahoe. This includes the BCM. It uses mostly negative inputs from analog switches, class-2 serial data to operate all of the body functions. Power seats, windows, interior & exterior lights and locks / in-locks doors and much more. But getting older, I use the interior fuse block on a sliding bracket easy to see. The bulk of electrical activity goes thru under hood relay fuse centers. Great, I can stand up to test & diagnose. The expense part would be these centers. Each relay is protected by its own fuse. The relay does the work, lights, fuel pump, high beams, horn and more. But this is easy splitting the circuit protection into 4 way large fuse centers. All together in one corner of the engine compartment but with a metal cover, sides, seal and clips in place painted to match the vehicle. But that is me. This is called “Resto-Mod” for adding fuel injection and feature from 2003 on a 55 year old truck and driving 2,200 miles and back without a single problem. Lab scopes are crazy good now! But for my budget, I would go with “Pico”. They have near real-time sampling but many versions use software on a laptop. Inputs are easy for 3 or 4 channels using digital to digital converted inputs. So an amp clamp around a fused jump in place or the fuel pump relay will allow you to see current jumping from brush to commutator plates and calculate the speed based upon unique anomalies and counting 8 plates X the sampling rate. You want a smooth consistent smooth wave form. Jumpy mean worn with lower than normal amperage. Smooth pattern with high amperage means plugged fuel filter (OEM w/rust) or pinch line, restricting fuel flow making the pump work harder. It was something I did when a customer want to check over before going on vacation! Easy, quick, effective! What do you do? Tell, teach and train. Sorry! Too passionate. Many Bubbas out there with tool boxes. Boats and tool boxes are expensive, but neither require a license to buy one.

@KissAnalog

Жыл бұрын

Thanks for this awesome feedback!

@deankay4434

Жыл бұрын

@@KissAnalog I am not a skilled electronics guy as my maternal grandfather was. He graduated with a degree in electronics in 32. What was on his final test? All questions about tubes use to make various devices? The transistor was being born behind closed doors. I simply look at a problem using common sense. It is the amperage being used to create louder output signals. You measure what is going in, not coming out. The make step-up transformers that increase voltage in the secondary, but at a loss of current. You don’t get both! The “Famous Audio Guy” in his video, use the out of an amplifier with math to show people how to pick wire size and the fuse to protect it. The barn door is shut so the horse can’t get in. Crazy! Has common sense left the brains of those who watched his video? Is selling larger wire & fuses that profitable! His follower made comments like; “You the best dude”. “I was wiring my new equipment this weekend, now I know how to pick fuses and get the correct wire needed to power them”. Are these folks serious! “Let’s install 3 big batteries in the trunk, 1 for each amp. Yeh, that will make it louder. Don’t you need 2 more alternators? I think that 4 more will do it and we can tape the wire to the door hinges. You mean the wire you got off that broken welder at the garage sale. Yes, new wire that big will cost me twice a much. Hey man, do you smell something burning? It smells, like electrical, like joes car that burn’t down after he spent that money on amps to run his 15” woofer and the 10 tweeters, in the trunk. Wow, that smell is getting stronger! I am joking around a little but the stuff I have seen is crazy.

Nice video! I like your way of explaining how class D amplifier works.

@KissAnalog

3 жыл бұрын

Thank you! I appreciate you!

A tad late to the show but , hey, I don't mind the seat at the back. Fantastic Explanation . I've got a bit to catch up on here with this class D stuff but your explanations are making it much easier to get there. Really enjoying the vids. Thanks Eddie. Great job.

@KissAnalog

2 жыл бұрын

Thanks so much - glad you made it;) I've got a lot more to do on this.

Hi Eddie, a great informative video. Thank you

@KissAnalog

3 жыл бұрын

I appreciate your support!

Nice video!!! Looking foward for the next video. Cheers!!!

@KissAnalog

3 жыл бұрын

Thank you. It should be up soon. I appreciate you!

Superb explanation. Thank you so much! 👍👌🙏❤️

@KissAnalog

3 жыл бұрын

I appreciate you!

Thank you for the profanity free education. It is very appreciated! God bless you sir

@KissAnalog

Жыл бұрын

Thanks for your feedback! I appreciate you!

Another great video, very informative.. Thank you..

@KissAnalog

3 жыл бұрын

So nice of you

very cool video! learned something today!

@KissAnalog

Жыл бұрын

That's awesome Pedro! Thanks for your feedback!

Excellent !!

@KissAnalog

2 жыл бұрын

Thanks so much!

@KenTeel

2 жыл бұрын

@@KissAnalog You're welcome. You did a great job of explaining things, utilizing simplicity to get concepts across. That's what a good teacher does: breakdowns concepts, into pieces, and simplifies them (sometime using alanogies), so as to facilitate a student's learning. I've had teachers that didn't use (or possibly understand this very important part of imparting knowledge on others.) You did a nice job, and I now feel that I have a basic understanding of your how class D amps work (basically filling and draining a capacitor to create a sine wave, using varying length duty cycles to accomplish this task.) Thanks for your work !! I love it.

Thanks, Eddie!

@KissAnalog

Ай бұрын

Thanks so much!

thank you so much !

@KissAnalog

6 ай бұрын

You're welcome! Thanks for the feedback

I've recently purchased a Fosi Audio DAC class D audio amplifier that is about the size of a box of kitchen matches. It produces about the same audio power that my old Pioneer 100W per channel amp does. And it sounds wonderful! Those really low bass notes come rolling through unimpeded. This thing is really efficient. Ahead of it is a tube preamp with tone controls to set the highs and lows. When I'm really cranking this thing all over the house; she barely gets warm! Phenomenal!

@KissAnalog

2 жыл бұрын

Wow - Thanks for the great feedback! I got to look into that;)

Big thumbs up

@KissAnalog

2 жыл бұрын

Thanks so much!

Back in the 1970s, the Harris Company built 50KW AM radio transmitters using this technology in their audio path to conserve power and heat. It was very effective. At that time and decade it was called pulse-width modulation. The 25KW power needed to properly modulate the 50KW carrier was generated this way. 90% audio efficiency was achieved. Modern audio class D amps are relatively speaking this efficient.

@KissAnalog

2 жыл бұрын

Thanks for this very interesting feedback!

Awesome video and nice gear

@KissAnalog

3 жыл бұрын

Thanks for the support!

Thank you for another great video Eddie. I tried the zoom trick and got lies from my GW Instek 200 MHz Oscilloscope! My fault pushing my luck. My 60 MHz Tek showed dashed lines to let me know that it was guessing. My old Tek 468 guessed about right though it is a 2.5 MHz one shot bandwidth. I was trying to measure fast fall times of monostables and capture the mono pulse width at the same time. Eventually I saw my mistake and triggered on the falling edge with a fast sweep speed. Periodic signals are less subject to operator error.

@KissAnalog

8 ай бұрын

Thanks for your feedback! Yes, periodic signals are much easier;)

Very nice video

@KissAnalog

3 жыл бұрын

Thank you! I appreciate you!

7:07 That is why some manufacturers of electronic devices use resin to cover the electronics after filling the smoke, so that the smoke stays inside :-)

@KissAnalog

3 жыл бұрын

LOL - great point!

Ed, nice demo, but I'm more interested into the scope you are using! I don't do almost anything in audio, but the scope has abilities that none of my scopes have. Mainly the spectrum analyzer side. Can you make more demo how that serves your needs? Thanks again for your videos!

@KissAnalog

3 жыл бұрын

Thanks Tony - I do have a cool video to do. I've been playing around with it and I'm ready to show the spectrum part of this oscilloscope.

thanks great video. one of the best on class D amps. I'm sure you could get more DMM's on your bench ha ha (Iam jealous had a set up like that when I was on the bench) Would have liked some n&d specs when its pumping 100W into 8Ω and to see what zero cross distortion if any?

@KissAnalog

3 жыл бұрын

Thank you! That’s a great idea when I get back to this amp!

I didn't know that James Hetfield have a good skill in electronic! 👍👍👍

@KissAnalog

11 ай бұрын

Yes he does:) Thanks!!

thanks for the video. Very informative. Do audio power amplifiers use DC power to do all their magic? When you plug a power amp into the socket, is it converting the AC to DC power to amplify the signal?

@KissAnalog

9 ай бұрын

Yes great question! The Amplifier brings AC voltage and then goes thru an isolation transformer and then converts it to DC voltage.

@dimitrisblane6368

9 ай бұрын

@@KissAnalog thanks! Do you have a video explaining how it converts DC back to AC signal as the output? Does it combine the DC from the power supply with the AC audio signal? How many volts AC do you get roughly on the output of an audio power amplifier? Sorry for all the questions haha

With WBG devices as power stage it's almost for sure the switching will be swift and clean. Im wondering the normal Si Mosfet based class-D amps, how they achieve 200kHz+ switching without using huge gate drivers. I mean, the speaker is a inductive load so it must be hard swiched, not that easy to deal with switching losses.

@KissAnalog

2 жыл бұрын

Thanks for the great question! MOSFETs today can easily be driven to 200kHz to 500kHz - in general. There has been big advancements in the gate drive (or charge) needed to drive them. Higher voltage FETs take more to drive.

So I get how frequency is modulated thanks for your great video… But I am still missing something… How is amplitude information conveyed? When you cranked up the input I did not see anything happening to the pulse width

@KissAnalog

Жыл бұрын

Thank you! If you look at the video at time 20:30 I start to show how the duty cycle changes at different points or levels on the signal. Let me know if that answers your question;)

@kansasnutt

Жыл бұрын

@@KissAnalog No I am still having a brain fart… It seems like the pulse width is related to reproducing frequency of the signal… I do not get how amplitude is conveyed… I mean the feta are in saturation or they are going off so how comes the voltage on the output it seems like it would always be at the rails… It seems like The total voltage rails would be delivered to the speaker at all times

@kansasnutt

Жыл бұрын

Eureka…. It’s really amplitude modulation relative to the average DC this is also a byproduct of the LC filter it is controlling the current to the speaker by giving an average DC to the speaker at any given pulse period

have done a multilevel class d with 4 halfbridges, 90 degree shift, get 5 levels, pre/post feedback/triangle with bessel lowpass. Unfortanely when I measure current over speaker in LTspice I get nice result with -100dB distortion level. But when I measure each bridge on on side of the speaker and the other 180 degree side, I get a very strange in fase distorted sinusoidal, using a emi filter do let it get better, so I think I deal with a common mode voltage? or differential voltage? Can I do something about it because otherwise the amp will be a 2 Mhz transmittor through the cables.. I can also use a half bridge 5 level with 4 halfbridges who do have not a strange sinusoidal problem, signal is very clean.

Sir please review infineon coolgan product of ganfet...am thinking to design full bridge class s using infineon products

@KissAnalog

3 жыл бұрын

That's a great idea! I'll see if I can get some. I like your idea;)

... off topic a bit but.... The day a college at my work was working on an "old school 240VAC Mains SMPS charger for a bank of even older NICAD cells, for some reason he had a brain fart, disconnected the GATES of the ganged MOSFET choppers not realizing they were in depletion mode in that state., then applied full mains into the board. The flash monumentally blinded him, the deafening noise made everyone jump & scared the hell out of us and yes the MOSFETs had totally disappeared replaced with large black patch of charring.... then we found bits of MOSFET impaled in the cortex ceiling 9ft directly above his workbench. If that stuff had hit someones eyes.... yeah, real lucky.

@KissAnalog

3 жыл бұрын

Wow - those are the stories I don't want to be part of! ;) When the Gate of a FET is left open, the gate capacitance will likely charge via Drain to Gate capacitance and turn it on - eeks! Great story! I've had those brain farts - and so far I've just had dumb luck;)

What I really don't understand is why, if we already have the data in digital form, we don't send it directly to the GaN driver, but first convert it into an analog signal and only then digitize it again...

@KissAnalog

25 күн бұрын

Great question. Not all input signals will be digital. My friend loves to listen to his records and tapes with his Class D amplifier. There are probably more analog inputs than digital streaming inputs;) In the future - this will likely change.

Nice video. I have a question about the "smoke test" you mentioned. I was using a square wave inverter, to convert my 12v battery to AC power for my induction cooker. I heard a high pitched buzzing, followed, by the magic smoke genie. I felt the inverter, and it was very hot. The inverter no longer works and has "High P" error message which means I probably fried a Fet or Cap or something. I was only doing 40 watts of power, which must have quickly fried the inverter. My theory is that the induction cooker only works on pure sine wave, so the inverter was trying to compensate by smoothing out the square wave, which quickly dissipated far too much wattage for the inverter to handle. Any thoughts on what happened?

@KissAnalog

3 жыл бұрын

WBETET It could be that the induction cooker pulls current at the crossover point - and an inverter that functions without true sign-wave switches at the power frequency - so slow and inefficient. With the wrong load, I could see a problem. Also the load could be damaged by the sharp edges. Great question - let us know how it turns out.

@wbetet6088

3 жыл бұрын

​@@KissAnalog Interesting theory. Never thought about cross over frequency. HMMM. Currently working with Potek Customer service to get a replacement. I'm curious to open up the inverter and see what component smoked! I'm also curious to test the induction cooker on a pure sine wave inverter and see if it has the same problem. I hope I don't smoke up a another inverter though!

@KissAnalog

3 жыл бұрын

I would think that a pure sign wave both switches very fast but also monitors the current at ever pulse. And because it is a sign wave the power pulled doesn’t really affect the inverters power factor as it creates a near unity power factor as its job. The low cycle - essentially a chopper with LC filter would be shifted all over the shop (to use the Aussie terms;) in terms of current and voltage relationship. I should try and get one to experiment on camera;)

i have a couple of D class amps that are receiving signal, but the output is very low, like barely anything coming out of the speaker.. what causes this?

@KissAnalog

Жыл бұрын

Thanks for the question. Did you find the problem? I think you reported this in a different post.

Im strongly considering dynavoice ca802bt Class D amp.Its light and small.Parameters tell me its good unit.Im curently using Philips mcm 760/12(its from 2008) mini hifi terminal with god knows what amp.All i know it supports 6 ohm speakers.Becus thats what it came with.Is it realy worth upgrading or should i wayt till philips dies and then look for something? Using wharfdale diamond 11.1

@KissAnalog

2 жыл бұрын

Thanks for this great question! That's tough question though, depends on how much you like what you have;) This is a low cost but good option I think: amzn.to/3CwcuXJ

Great video but you should be aware that the more often you release the magic smoke, the more subscribers you will have! :-D

@KissAnalog

3 жыл бұрын

LOL - you make a great point;) Thank you!

The output stage circuit looks very complicated for a full bridge design. Why so much passive components all around?

@KissAnalog

Жыл бұрын

Thanks for asking! I'm planning on doing a series with a new design based on this, so we will cover all aspects;)

Can a class d amplifier work on a switching frequency of 100khz? What are the pros and cons?

@KissAnalog

Жыл бұрын

Thanks for the great question! The 100kHz might be a bit slow and would require larger inductors and caps at the output to filter the notches between the pulses. This might also be too close to the audio frequencies.

@deejayobenn160

Жыл бұрын

@@KissAnalog Thanks.... Inductor caps you mean?

@deejayobenn160

Жыл бұрын

@@KissAnalog if a mosfet used in class d amplifier is rated 200v maximum, what are the safest operating parameters in terms of voltage

@KissAnalog

Жыл бұрын

The FETs should have a higher voltage rating than what will be applied across them. It is much safer if the voltage rating of the FET is 30% higher than what is placed on them.

@deejayobenn160

Жыл бұрын

@@KissAnalog higher than 200v example?

Pleasant man not eggheaded and arrogant like many. Unfortunately I understand about 10% which is a shame because I'm about to put a 200amp class D kit together and my smoke test will either be a sucess or a big fail. I suppose I should make it my business to understand a few tests to prevent waste.

@KissAnalog

2 жыл бұрын

Thanks so much! I appreciate you!

Don't normally need a positive and negative rail for Class D. H-Bridge as I'm sure you know takes care of this. 200Mhz scope with 1GS/s, too slow.

@KissAnalog

3 жыл бұрын

Thanks Jeff! I will do a SMPS design with a Class D as soon as I can. Should be a fun project with a lot of side stories;) Why do yo think it is too slow? I’ve had no trouble working with these supplies so far. Looking at the rise time of a GaN FET might be a challenge but has been ok.

How and why SHD and THD effects an amplifier ?

@KissAnalog

3 жыл бұрын

Thanks - great question! You want your amp not change the signal but just amplify it. If it distorts the signal - causing Harmonic Distortion, then that is not good;)

Si4. Why do you have so many test instruments cluttering your workspace?

@KissAnalog

Жыл бұрын

Thanks for asking;) I do need to clean up - but I always have 2 or 3 projects going. Also, I show equipment in the background after someone from Siglent recommended that I do for eye candy. But it is messy now;)

you definitely need more Voltmeters and MMs , those 20 wont cut it

@KissAnalog

2 жыл бұрын

LOL I might get another one;)

Really difficult to follow .

@KissAnalog

9 ай бұрын

Sorry about that. Maybe this video will help: kzread.info/dash/bejne/a2ukmKSkcbC6mc4.html

10/10

@KissAnalog

7 ай бұрын

Thank you!!

You seem like a nice guy. But I am on minute 7 and we haven't gone anywhere

@KissAnalog

3 жыл бұрын

Thanks for that feedback Thomas! I am going to work on that - and try to make the vids more efficient in time. I say that just as I’m ready to release a review video that is way too long - and made me really want to keep this from happening again. The length of the video also exponentially increases my editing time. Ugh!

Who invented class D?

@KissAnalog

2 жыл бұрын

I looked it up;) Alec Reeves, a British scientist in the 1950s. Great question!

@VicariousAdventurer

Ай бұрын

My teachers, grading me?