While it sounds good at low to moderate volumes, it’s definitely noticeable at higher volumes and very present with headphones. I tried every grounding possibility, changed cables, moved the power cables away, changed the load and gain settings but nothing clears up the hum. I’ve seen some threads on other sites about QC issues but I like the way it sounds other than the hum. My other pre didn’t have any problems with noise so I don’t think it’s my space. I don’t want to return it if I don’t have to since it was rather discounted and I doubt they’ll go for an exchange for a new one . Any ideas?