Audio out noise when charger plugged in

I’m getting a very audible hum on my headphones plugged into the audio out when the projector is connected to power. This remains the case both in HDMI and standalone Android modes. I’ve tried two different power supplies and three different headphone types and all of the combinations of those present the same problem.

Is this a manufacturing defect? How can I go about resolving it?

The same on my 2 projectors when connected to the power.

Same issue for mine. I plugged a jack cable and it’s gone. feels like a hack but it works…

What do you mean by ‘a jack cable’? My headphones are terminated with a jack already.