Looking to move my second Questyle CMA800r Amp. These are “current-drive-esq” and were made with the HD800s in mind. It added a much desired thickness while keeping all the details. It also worked pretty well with almost all my headphones. (Atrium, Audezes) These can be run in a pair as mono blocks. Which in my experience did what monoblocks usually do. A bit blacker, more separation, a lot more driver control. A decent-ish difference for headphones but not make or break. There are a couple minke marks on top from the rubber feet when they were stacked and monoblocked. $800 OBO The special Y cable to run monoblock is included!