Ok,
In this mornings fun I swapped out the Premp and connected the Dac direct to power amp.
Slightly less hiss, but sound quality dropped away, sounded flatter and more like a recording of a song rather than people playing instruments in the room.
So back in went the Pre.

Funny thing...
I’ve kept the Rotel amp powered on since I first hooked it up, either my brains getting used to it or there’s less hiss from the amp with some hours on it now.
If it hadn’t been switched on since January this might make sense?

Maybe the amps stabilising a bit after being off for 3 months...
Anyway, whatever the reason I’m happy to say I don’t really notice the hiss anymore.

Cool.