I want to play my 4 ohm 3 watt speaker using PAM8403 module .But when i try to power the device using USB power from pc it shows noise .but from different power supply like mobile charger . It shows no noise .So now 5v power is from usb mobile charger and aux from pc.Amplifier module
Connection
+5 and GND -> USB
Left,Right,GND -> AUX
Since the mobile charger works fine, use a separate 5V power bank instead of USB power from the PC. This prevents ground noise from affecting the audio signal.
i got that but how to fix this issue
The application notes for the amplifier chip tell us the module does not have adequate filtering for the power. Seems like the mobile charger has the needed filtering.
Look at the data sheet for the PAM 8403 for proposed capacitor values to correct the problem.
You fix the issue by not using you PC as a power source.
You are pulling more then the port is rated for. It is probably starting its protection mode.
USB power is notoriously noisy. This isn't a problem with digital data but it can cause problems if it gets into analog audio.
Try what I call a "Half Filter":
The diode prevents the capacitor from discharging back into the power supply or other electronics which makes the filter very effective on negative noise spikes. On the positive spikes it's a little better than a capacitor alone because the capacitor tends to stay charged-up near the noise peaks.
Where it says "To Arduino" that should connect to your audio amplifier. The diode should be a Schottky diode to minimize the voltage drop but you can try a regular silicon diode first if you have one. And of course a bigger capacitor will give better filtering.
