I was kind of nervous before purchased this pre.
First, I just entered 500 series world.
Second,I already in love my UA-610 as my go to tube pre.
Third,this is the most expensive 500 series pre.
But,after weeks search from so many forum, I decided to call Michael Grebe from Sweetwater to purchased. He sent me one last week(together with API 512c),and I was blown away. Everything sounds huge through it. Vocal was great,,guitar,kick,snare,you name it. Another surprise, it's so quiet for tube pre. Kind of clean sound,but if you turn hard the input,sound so dirty in a great way. I love the character, quietness, and the way it's looks.
As I typing this review, my second 583s just sent by sweetwater yesterday.
I have the feeling my LA-610 with start collecting the dust in near future.