I have a powerbank with which I would like to power a panasonic gh5 and even a mic preamplifier connected to it. The problem is that when everything is conected, a strong disturbance is probably linked to the ground loop problem. When i connect the preamp with a battery apart the sound is OK. Some ideas on how to solve this problem. Thank you ! I upload an image https://ibb.co/h1N6FYG