Unfortunate hiss with Massdrop Univ Plus IEM and e17k

Hey guys, I just picked up a pair of Massdrop Universal Plus IEMs. These sound super clear when using my phone as the source, but when I use my PC with the e17k I hear a slight hiss. This happens even when the audio output is disabled -- it seems like simply being plugged into the e17k (when powered on) the hiss occurs. It's very slight, but it would be great if there was a way to remove this. Thanks for any help in advance.