Class D Audio Amplifier Hardware Design - Phil's Lab  

Thanks for watching! Next video well be a full KiCad 7 + STM32WB Bluetooth design! Any project ideas (similar size to this Class D board) that you would like to see?

You really made a half hour video just so you can show off your guitar skilles at the end xD I really liked the design, learnt a lot!

Not only you can design the board, but also you can play guitar nicely. Gifted.

Im already in admiration of you EE/PCB design knowledge but hearing you shred at the end! Wow, you have my dream skill set 😂

Audio projects are always great -thx

Kinda late to the party but just wanted to say: Always a delight to see a notification from your channel Phil. Great as always. More audio projects please! haha can't get enough. Cheers!!

Super interesting video. Impressed with the results and the demo at the end. Thanks!

Ive been following your channel for a few years now(as an EE ive picked up quite a few tips) and as an music/audio lover im always stoked to see these videos. Many thanks Phil, cheers!

Man, the timing of this video is incredible. I just thought about giving pcb design another shot and you happen to have a new video on exactly what i wanted to do.

Big fan of the RU-vid channel and keep going with the experiments. We could easily replace guitar amplifiers with class D technology as the closed loop bandwidths can go up to 120Khz or more. Then its just a matter of maximizing the performance of the design along with the X-Y transformer/amplifier hysteresis. Then you go further on to decide how many switching levels you want, what switching speed your targeting for, and filter options such as post filter feedback..etc.. That is how I went down that rabbit hole :D

I really enjoy watching your hardware design videos! Especially the easy to understand schematics, layouts and explanation are fantastic. Your videos have helped me boost my knowledge about electronics alot and got me some internships where i was able to useethat knowledge and show off my altium skills. Thank you so much!

I guess the most precious about audio design is the technique of laying out the pcb tracks in order to reduce unwanted interference to the maximum

Hell yeah, SHRED! As usual great, informative video! Good to see you QA403 arrived. Mine should be here this month :)

Thanks for the tips and the great solo!

I never thought much about it but I guess an 89 dB s/n ratio for a power amp is quite normal irrespective if it's class AB or D or whatever? Certainly it makes you think a bit about fretting about material being captured at 16 bits as opposed to 24 bits.. Nice guitar work in the end :) i used to play with Yngwie in the 80s (played keyboards on the first five or so rising force albums)

Have recently designed a DC switch power supply useing your vids as baseline advise and it turnd out pretty ok for a first time using kicad for PCB Lovs your vids man keep it up

Thanks a lot for your videos. They are so informative

Nice video, well done thanks for sharing it :)

Sounds great and you play guitar really well!

Great video thanks, also the usage of the QA403 - mine still on backorder, hope getting soon.

Excellent coverage. I followed along while looking at datasheet. Your layout is much tighter than TIs, good job here. You've opted for a different thermal relief strategy based on experience 👍. The sheet says in 7.3.7, "In a single-ended input application, the unused input should be ac grounded at the audio source instead of at the device input for best noise performance." Not really possible with a guitar/pedal combo with various grounds floating around. Thanks for the video, I'll start using pours more often than wide traces.

I use a TPA3116 as a stereo power amp, which follows an ME-80 signal processor, so far it worked nicely. The only downside is with 50W of power, it's simple not lound enough. Looking at some discrete design now.

Thanks for sharing! Maybe not so critical for a guitar amp, but interesting nonetheless: TI Paper "Selecting Capacitors to Minimize Distortion in Audio Applications" (Zak Kaye), describing how a cheap X5R input cap on these class D amp chips can create 30+ dB more THD+N instead of a through-hole film cap. Depends on frequency and other parameters of course, but highlights details that distinguish an audiophile amp from a standard amp.

The cross talk and emission of these inductors will be a blast 🤐.

Nice shredding!

Well, I enjoyed that!

An Aluminium substrate PCB might be the way to couple the heat into a heatsink.

Fantastic

damn , that play was epic .

Very cool! Thanks for breaking down the operating model for the class-d up front, it really helped with understanding the overall design. How feasible would it be to combine USB-PD and a DAC + this kind of amp to create computer speakers? Guessing most motherboards don’t supply enough power?

Great video (and great taste in guitar gear) as always. Do you think you can expand this power amp to a full guitar amp, jfet preamp with cascading gain stages and a real tonestack from a vintage amp? As far as I know, the tonal characteristic of an amplifier (other than cab and speaker) comes from the tonestack. So in theory, you can create an amp that sounds like some historic amp only by implementing its tonestack.

Great project! As always, appreciate the breakdown. Are you into symphonic metal? :D

What I missed or do not understand is; you are connecting a balanced signal to a mono jack, right? This goes to you speaker cabinet. I thought these are speaker connections where mono unbalanced. At least if it was balanced wouldn't you use a balanced signal with ground over a TRS?

Once I played around with simple class D on FPGA. It is really fascinating that any signal can be generated by single digital pin. However main frequency should be far more than actual signal frequency, which is limiting factor.

very nice video abou the class-d board. One thing I noticed are the thermals on the barrel Jack power supply, they seem too tiny. Is that enough to link the main rail track to the barrel jack? your lovely guitar sounds the cool new entry into the video!!!

Looking forward to the discrete Class D amplifier design video because I mainly work with high-power audio amplifier designs and Class D amp chips for high power do not deliver what they promise.

Cool ❤ both electronics and guitar. You should try some guitar staff on RU-vid too. 😂

If you want to use it as a guitar amp you should have shown on the scope how it distorts when overloaded with a pure sine wave. Another good test is how it amplifies a square wave.

Phil, when do you sleep? Great content as always...

I have a question that popped into my mind watching the start of the video explaining the basics. I get the Low Pass filter, but in order to fully utilize the swing of the speaker coil you'd want also a high pass filter (let's assume -6dB@50Hz) to get rid of the DC component. If you i.e. run it form 0 to 15V you'd lose the -15V range but if the resting potential was -15V any silence would burn up your speakers. I know that i also could be very wrong, bc. i'm stoopid :-D For clarification, i do electronics professionally, but i never had any in depth contact with audio stuff.

As always very nice video.. I've done recently a TPA3255 based class-d amplifier with a PFFB and the sound was AMAZING! But I've a question please.. would it be better to put the electrolytic capacitors on the top of the board and place the IC on the bottom side so your power loop inductance will be minimized even further? Because I've done this trick on my board.. thank you!

Phil out of curiosity, do you manually place the crosses over the DNF components in the normal schematic view, or is there a way to show it without entering the "variant editor"?

What about some DSP implementation in FPGA video?

Can you use kicad for pcb design?

Thanks for another excellent video. Question for you regarding power supply. What is your take on using one of these usb-c chargers - that start to accumulate unused at home - together with a PD chip on the board for an amplifier like this? The common ones can supply 60W and up to 20V that seems about right... Would such power supply be too noise? Would the filtering caps that you used in your design be enough to get decent results?

@PhilsLab Did I miss the input impedance being set to 1M+ for the guitar input, or are you loading the pickups a bit?

Thanks, always get some loose ends

I notice you use a lot of thermal reliefs. One that stuck out to me was a thermal relief on a powerpad ... I dont know that i've ever seen that before. I suppose you are trying to keep the board hand solderable, right? Great video, but I found that intriguing, so thought i'd ask, as knowing you, it is not without reason.

Why you choose 1u tantalum caps at the audio inputs? What about the polarity?

Hi, does anyone know how to display not fitted components in editor's tab as in Phil's video at 9.47? He also doesn't have any variants for this project, I am a bit puzzled how he was able to do that. Anyways awesome video

in case of it will drive 50W on 8 ohms speaker - output AC amplitude should be about 28 V.. how will it bring 15V to 28V? is there integrated boost coverter in IC? if yes - where is the bulky inductor coil?

Electronics is right, but the real question is: wich string gauge and string action u use Nice video as always!

Steve Vai's hands there!

Very nice playing and pcb design! IMO, damping factor of class-d chip amp is way too high for guitar to sound good, way less “punch” than a push pull pentode tube amp. Do you have any idea to lower the damping factor of 3116? Cheers!

If you prefer EL34 to KTxx you might like MA12070 more than TDA...

can make esp32 a1s with tpa3116 pcb?😁😁

I've been meaning for a while to design a class D amp with I2S digital input and feed it directly from FPGA. I wonder what kind of latency this system will have.

👍🙏❤

Play at 0.75% to understand

Ever done any tube audio stuff?

You should've placed the guitar part in the beginning 😅

woah, wen collab w/ Max Ostro? :p

Deerfield I was wondering if you could do me a favor and maybe help me with an issue I'm thinking about upscaling E-Waste repurposing and recovery as opposed to just burning it up and recovering the metal because I live in a country where the E-Waste is thrown away are fully functional MacBook pros and New Generation in micro laptops and desktops and I think it's absolutely ridiculous to burn them for their metal and it would be much better to repurpose what can be repurposed and then you know dispose of the rest but most of the stuff can still run manex super fast and is absolutely good stuff for countries where the classrooms need computers just to be competitive in the world. So I was thinking of an SSD design where you recover all the storage from old thumb drives and old sticks and your repackage them into strips by type and buy a generation and then have an SMA automatic calculator place them on a PCB that has a small fpga and USB connector as his required by the EU and use a double-sided bored and have the fpga to a diagnostic of all the chips that have been placed and don't map any of the faulty or potentially failing sectors. In addition run kind of a raid array on what is there just so that they're reliable and it's all accomplished on board on the fpga. If you can order me the removal and replacement as well as the sorting and packaging it could really save and help and reducing what gets burned and what can be reused. The FBA GA would run the diagnostics and form a raid array of what's there to provide redundancy and resiliency considering their second hand. Also to buy a any cheap but reliable copies from any Source already enrolls to produce reliable maybe not the fastest or the best on the market but good solid working drives made from E-Waste and where I live they throw away the best stuff in the world I mean I recovered out of one bin that my neighbor who has a company lets me fish in and I recovered two working Apple MacBook pros and all kinds of stuff from usable and security resilient switches and Poe switchesand I even recovered a security device that I think will accept pfSense as a firmware upgrade. So just for me putting this stuff to use instead of having to end up in a waste disposable or put in a kiln or ship to a third world country where it talks about the people and the environment just to recover the small amounts of metal that remains in them is still going to happen but the last thing we send in the morning material we can recover and place back into use for education in schools and you know the power supply from The Towers can easily be turned into very safe and very accurate and precise desktop power supplies with a simple component from of course China but it could easily be redesigned here but they just haven't you know the connector for the board right there you snap it in the even include included fuses and then I'm going to take off the switch they have on there and put a proper switch and put a voltage regulator

Cool, but connectors on 3 sides - come on, also whats the point of thermal relief under the ic - during reflow its all the same, but now we are not using the top layer for cooling, my choice would be moving vias just beyond the pad, not using relief - no wicking problems and probably better cooling. 15v power is weird as well - 24v is better and more common and you can still use anything 15-24v.

#DemoTooShort:(

class-D amps sound like crap, especially for guitar