We talked about my experience with the LHY ock-2 on another post. As mentioned, I noticed a slight improvement when using the ock-2 with my U18 ddc. I don't notice much difference using it with my Gustard X30 dac.
The game changing moment came when you asked about using square wave outputs on the ock-2. I had not tried that, so I gave it a shot. This made a very noticeable improvement in clarity, separation of instruments, etc. It's still connected that way....