Great Value in Used Phono Preamp’s?

Hey, Folks!I am looking to increase the quality of my phono stage. For many years, I have been using a Bottlehead Seduction that I assembled myself. It’s been great, but  having spent some time with a borrowed, integrated amp with a really wonderful phono stage built-in, I think I’m ready to upgrade.What would you be looking for, used, in the $500 range in a used phono preamp? Thanks in advance!