New to Hi Rez Audio

Hi everyone, I have an old Krell system I want to integrate Hi Rez audio into but unfortunately I do not know where To begin. I’ve been looking at players but just don’t know what  I need. Any help will be great. I’ve read reviews on the Cambridge Azur 851n and that looks promising but since I have a Krell preamp do I really need to spend that much? 
Thanks