This sounds like a lot of BS. I feel sorry that you never had a silent gear. My first encounter with hiss was many many ears ago with tube amps, that probably was normal. Then I discovered computer music and everything became silent until earlier this year when I got iFi iDSD. It had hiss and lots of people tried to convince me it was normal, but it wasn't. I privately contacted some other owners and their units were silent. I struggeled with my decision, but decided to return my unit and not exchange it. I did not want to take another chance(company knew there was a problem with some units, but never acknowledged it publicly) So I went back to my trusted setup of ODAC -> LakePeople amp, it is dead scilent with any headphones, even at full volume with no signal, just a connection.
To state it again "all amps do have hiss" is a MYTH that defective and poorly designed amps/dacs have. It is up to you if you want to live with it or not.
I know which one I choose - I prefer silent, the only hiss I hear sometimes is the one in a recording, because it was recored on older analog gear and it gives some of them a charm, an example would be "Raising Sand" by Robert Plant with Alison Krauss , but I wouldn't want to hear it all the time, no way.