Today 02/13/2021, completing about 1 year, I started to notice these noises, hissing without change for gain, nothing related to the cabling and audio connections. I have an Eris 4.5, and from what I understand from those comments, everyone is having the same problems. Disappointed with this being proven to be a design error on the Presonus internal circuit. I'm from Brazil, my hands are tied.