First of all a big thanks to John from Burson Audio for contacting me and sending V5i for free in exchange for my honest opinion. I am not a reviewer and this my first review, so please bear me with this review. The installation is very easy and simple. My headphones are HD6XX, E5000, Kanas Pro and FiiO EM5 paired with XDUOO-XD05 Plus + FiiO M11 Pro I was not able to find much differences vs the stock OPA1612 initially but as I spent more time with it the differences became more apparent. The first and easy difference I was able to find is...