Guys I built a Bluetooth Speaker with a 2 3w 4ohm speaker powered by a PAM8403 amplifier supported by 5v 1A powerbank charger module and for the bluetooth i have used a USB powered bluetooth adapter
Now while connecting 5v output from the powerbank module is connected to the +ve and -ve of the amplifier module and the same wire I removed the sheath connected a B0505s-1w dc -dc 5v-5v isolating converter to the respective +ve and-ve wires and the output from the converter to the Bluetooth Module
Problem1: Ground Loop Sound Interference still exist
Problem2: Slight heart beat like thumps from the speaker
Can anyone help me find a solution to this?
Thanks in advance

 

The powerbank charger probably produces hum and pulses that a battery does not care about but your audio amplifier needs a properly smoothed power supply.