Years ago, when they first were sold, I had a C-4000 but had to sell it. Recently, I wanted to return to the pre-amp but I was hesitant because of its complexity and age. Luckily, I found Nelion through the Carversite, and reading the recommendation from Bob Carver about Greg's work was all I needed to see. I bought the nicest one I could find and shipped it to Greg. I received it last week, and it sounds fantastic. I can't take my eyes off it, and can't stop listening to it. Although it is a complex piece, if you truly admire Bob Carver's work it's a privilege to have one of these as the heart of your system, and it's great to have Greg and his team to bring it back to spec and beyond.