I never had luck when mixing a computer and an amplifier, I thought that this time would be different since I am running everything on a single powerful battery. Sadly nope… I can hear my mouse moving or any r/w on the sd card is well represented with noise & glitch.
Let me explain my setup a little bit better, I have a battery with 5V connected to the rpi, the same battery also have a 12V output connected to an amplifier. The amplifier and pisound is connected (and grounded) via the lineout. It’s very noisy as you can see in the video (see below).
If I keep the 5V -> rpi but feed the amplifier from my bench power supply = no noise at all (part 2 of the video).
I am no expert at this kind of thing, ground potential difference, battery power, virtual ground… If someone have an idea I am all ears. Maybe there’s a bandage that could fix easily this situation (I am thinking of using a DI direct input passive box?!).