I’ve noticed a slightly different noise issue. It only occurs when I connect the H90 to my MacBook Pro via USB to use the H90 Control App. As soon as I connect the cable, I get a noticeable amount of “computer noise” coming through my Scarlett 4i4 audio interface (same issue with my Scarlett 2i2). This is not 60Hz ground hum. It sounds like it’s a function of what the H90 processors are doing… kind of like if you float your cellphone over your guitar pickups. As I navigate through through the H90 Control App, that pattern of noise varies slightly. I’ve tried a couple of different US cables… same issue. Any ideas? Is there a USB “isolation” device?