I just my hands on the KANN Alpha today. I haven't specifically tested the Hero, but the KANN Alpha has a Low/Mid/High gain selector, and with the Mid gain setting I had zero hiss on any of the IEMs I tested. Based on the time I spent with the Hero, I'd be quite confident that the KANN Alpha would have 0 noise or hiss. I'll check it out specifically tomorrow though to see how it does.
When using Hero with the Kann Cube the hissing was very minimal if any at all (I didn't notice it). I imagine that the Alpha would be the same.
Thanks a lot for the quick replies. This is really helpful, I am excited to hear your impressions with the Hero. Thanks again