I don't have anything quite in the HE560 area, just a set of HD6XX's and a pair of HE-4XX but I agree, the Cayin is a monster for its price. It can drive my somewhat-hard-to drive phones quite well and it's my go-to portable amp with those cans. 800mW (32Ω load) for 200 bucks, that's a good deal...I've just got it lined-out to my FiiO X5III and on high gain I get very decent headroom, bass boost is a nice option too. The C5 was my first foray into the Head-Fi space back in 2015 and it has been a reliable piece of kit like no other. I've got a couple of other portable Amp/DACs, and while they offer their own unique features, when you just want simple, clean power the C5 is it!
I agree. I don't know how it does it. Small form but big clean sound.