https://community.element14.com/technologies/open-source-hardware/What is the connection between Open Source Hardware and traditional engineering companies. How can professionals & hobbyists learn from each other. What can hardware developers learn from Open Source Software.en-USTelligent Community 12https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235168Mon, 27 Apr 2026 08:48:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:44452ced-abbd-44a2-abef-afcd502f4407geraldsHi, please take a look in this datasheet. https://www.alldatasheet.com/datasheet-pdf/view/246505/PAM/PAM8403.html -> page 10, figure 2: here is a description about an EMI filter, which helps to reduce EMI. It seems your amp_PCB is not RF stabile; its layout is not optimized as well. Its GND trace is very small. As well your PS_PCB please reroute for low noise and low impedance. -> short traces as you can do, separate in-going from out-going, signal traces need pairing (parallel going) with GND not with V+. 3W output at 5V supply produce a relatively high and fast impulse current into the speakers, separate is it from input traces.https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235166Mon, 27 Apr 2026 07:04:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:5ceaba93-4ba6-4cac-a60b-591f697e428eshabazIt's difficult to completely remove noise when a lot is outside of your control; even some so-called hi-fi products get noise artifacts when things are interchanged in setups the manufacturer didn't expect. Are you sure you're not expecting too much; what is the noise level in comparison to the audio level, and what does the noise sound like? Could you record it? I happen to have one of those PAM8403 boards here, but I've never used it. I've buzzed out pin 8 which needs to be connected to a bypass capacitor according to the IC datasheet, and confirmed it's present, so the basic minimal circuit is at least implemented on that module. I will try to power it up sometime, but no guarantee I can do that this week. Not sure it would be all that useful to you anyway, since I don't have the same setup as you. If you can power-down everything else (LEDs/microcontroller), and remove the input (and maybe even short the inputs) then check to see if the noise is reduced a lot. Then try to add in the audio cables, and feed in audio from something completely separate and battery-powered to begin with, such as a portable MP3 player. Just take baby steps, and see what affects the noise. I suspect that you may eventually reach a point where the noise is low, but still noticeably there, unless you're prepared to change things a lot, e.g. say switch from USB power to battery, or not use the LEDs/microcontroller if not required, and so on.https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235163Sun, 26 Apr 2026 19:21:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:1fc334d6-579b-4ac5-a5f6-f328c363310eacdc90can you measure the current the complete led circuitry is drawing? and try an inline choke to power the leds maybe a photo of the old board and complete unit ?https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235162Sun, 26 Apr 2026 10:01:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:cbdcb0ac-9924-47ab-a1f2-93adf0a8c551me_CrisI have some PC speakers powered by 5V [USB], the original board had a digitally controlled amplifier [via push buttons] and an unlabeled IC [for LEDs], all on the same board. The PAM8403 is a module soldered onto a PCB, and for the connections I had to use JST connectors. I don't know much, but I'm still experimenting.https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235160Sat, 25 Apr 2026 22:57:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:df4d66c8-3193-46c8-bb27-5eeb07289c93Gough LuiMost likely this is just digital noise coming through - you need to make sure you've got good routing to avoid it being picked up, good ceramic bypass capacitors nearby, ideally a separate analog ground plane that joins the main ground away from the digital and perhaps even consider some kind of filtering on the power (e.g. inductor choke) if it's really bad. Ensuring the bypass on the LEDs is good is also important, especially if you have a bad ground, the noise could come around due to ground bounce. The addressable LEDs are PWM so they switch on and off "hard" and that modulates your supply and power distribution network. Personally, I'd say using a differential input audio amplifier, rather than a single-ended type like you have, would be a better choice and routing pairs of audio lines to that amp, that way if the noise is induced, it is induced into both legs of the audio signal and thus cancels out.https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235158Sat, 25 Apr 2026 20:21:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:6a80f1f9-b435-4648-bfc3-756ce0082a39me_CrisIt's a single PAM8403 (the little circuit you can buy anywhere). It's a single power line, 5V via USB (so lots of options). I put in several capacitors to support the power. The old board contained the amplifier and a controller for the LEDs, but it is damaged.https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisy/235157Sat, 25 Apr 2026 20:00:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:0b2c9eeb-4dc2-4396-b062-72a77ad7421bacdc90i can see you have 3 seperate capacitor groups, Are you going to have 3 seperate amp boards,? where is the 5v coming from is it from a switch mode regulator or battery controller,? does this regulator have a biger size cap like 220uf where you are getting your feed from? can you make a second regulator to supply the leds seperatly ?https://community.element14.com/technologies/open-source-hardware/f/forum/56877/the-pam8403-amplifier-is-very-noisySat, 25 Apr 2026 15:37:00 GMT93d5dcb4-84c2-446f-b2cb-99731719e767:ad54b1b2-17e9-4eac-ab4b-1a78ab70ce19me_CrisHi! I was thinking of participating in a challenge but I ran into another challenge. I'm using a small circuit with PAM8403 as a replacement for some speakers with dead audio circuit. In addition, I also have addressable LEDs in the case (this how they came) and I was thinking of using an MCU to control them. But I just noticed a very sharp and annoying noise produced when I power the LEDs, and it doesn't go away even when playing music. I made a msall PCB, the schematic is below. The power supply is at 5V [USB]. I placed some capacitors in the idea to support the supply voltage. What ideas do you have? What could I improve? Thanks!PAM8403ws2812