Electronics > Projects, Designs, and Technical Stuff
PAM8403 Amplifier suddenly clicking and dying
8bit_coder:
I bought 5 Class D PAM8403 amps off of Amazon. I was testing one of them with two 8 ohm speakers and everything was going smoothly. I was listening to music at a low volume, and I kept checking the temperature on the amp chip but it never got warmer than room temperature. Suddenly, I hear this loud clicking noise from my speakers. I managed to disconnect the amp from power quickly, but now it only clicks.
I managed to get a direct recording of the clicking sound: (warning, loud):
RIP PAM8403.wav (1022.24 kB - downloaded 126 times.)
After letting the amplifier sit for a while(it got hot to the point of burning the tip of my finger but no smoke, while it was clicking) I hooked power up to it again and now it's dead silent, unless I play a really loud square wave of one hertz on my computer, I can hear a loud clicking along with the one hertz my computer is playing. I can somehow increase the frequency of the square wave up to about ten hertz and then it starts getting really hot again, without releasing the magic smoke.
What happened? I'm genuinely curious as to what happened and what was the fault of it.
don.r:
Getting hot = something has shorted. Likely a failed transistor. Class D is a switching amplifier using MOSFETs on the outputs. Here is a quick guide to test them, best tested out of circuit.
8bit_coder:
I'm wondering what would have made it short so spontaneously? It was working fine a minute ago and then it suddenly dies? That's weird.
Zero999:
What was the supply voltage? Did you check is wasn't above 5.5V?
How long are the speaker cables? I wonder if having them too long could cause high voltages to appear at the amplfier's outputs.
8bit_coder:
The supply voltage was a constant 5 volts from one of my trusted USB power banks, and the speaker wire length was about two meters long.
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