Building Bluetooth stereo

I am trying to build a Bluetooth stereo for my son. I bought a amp board 50 watts/ side with 100 watt subwoofer output. The amp requires 12-24 volts dc power. The Bluetooth board requires 5 volts of dc power. 

I am trying to figure out how to have the units connected  together, both with their respected voltage supplied without getting horrible noise. If I connect the units to two separate power sources they work fine, but as soon as I try to run them off of the same source I get noise. I have tried running 110v in to the unit, splitting the power with dc/dc buck converters, again noise and again it no noise if I run power to the buck converters through separate power sources... I really do not want to have to run two power cords to this unit.... help