Digital Noise when sharing power with amp

Intelligent_Instruments_Lab

Greetings from iil.is

We are experiencing digital noise on audio out from Bela Mini with Audio Expander when powering it from the same power source as our amp. Listen here for an example of the noise:

The system consists of:
3x Cycfi Nu pickups coming in to the bela powered from a separate 9v battery (learned that the hard way, this is Halldór writing).
A 50w amp connected to Bela Mini Audio Expander out running a 20w transducer (in close proximity to the Bela and amp).
The Bela and amp are both powered from the same USB powerbank.

thoughts?
Best from the lab!

giuliomoro

Intelligent_Instruments_Lab The Bela and amp are both powered from the same USB powerbank.

I'd recommend having a dedicated power input (i.e.: no shared ground) for the power amp, otherwise you'll get a ground loop which causes the issue you are encountering. Alternatively, if your power amp has a balanced input you should be able to drive it with a balanced signal from Bela.

Intelligent_Instruments_Lab

Thanks for your quick and helpful reply Giulio. Balanced signal looks like a resolution to our issue. We will post a description after the current deadline.