Hey gang. I have an older laptop (ASUS) with a Behringer UMC 204 HD. It is bus powered and sometimes i get a nasty ground loop sound when running my guitar through reaper to the PA. For a long time I couldnt figure it out because it was intermittent. Tried many things until last night I unplugged the laptop charger as soon as it came and it went away. Plugged the charger back in and the sound was gone for about 40 minutes or so and it came back. I unplugged /replugged the charger to solve. Any advice here?