Yes, true, but do you think it will work at all? In other words, do you think that part that I linked will successfully take the car 12v power as it source, and correctly output 5v that the Arudino and the Bluegiga can run off of?



All of the above. I'm hoping that it's noise from the power supply specifically, and not anything the empeg's audio outputs are responsible for.

The reason I'm thinking that it's the power supply is because I don't have any noise as long as I am powering the arduino and the BlueGiga board from a separate 5v power supply that is not the same power source as the Empeg, i.e., the empeg gets its power from either the car 12v or a home AC adapter, while the arduino+blueGiga get their power from the USB port of my laptop in battery power mode. As soon as I power them all off the same 12v supply (the empeg directly off the supply and the Arduino/BlueGiga off of the pololu 5v converter off of the same supply), then the noise appears. So I'm hoping that an isolated power supply will do the trick.