I only hear a little hiss on my Simaudio Moon LP5.3 RS when the volume is at the max.
That doesn't mean you phono has an issue - all phono stages are different.
Have you tried this with JUST the phono stage connected?
- i.e. assuming you have other components
Whest make some very good products - perhaps send them an email and ask them directly.
If I encounter an issue I always disconnect all other components
Regards - Steve