Our drivers will get decent volume with most devices, even cell phones. However for the best sonics we recommend 100mW at 300 ohm impedance out and 300mW at 300 ohms is best to max out the driver. Of course it's OK to have headroom (wattage above max). ZMF headphones do not require any...

I'm selling a like-new Sennheiser HDV820 purchased in October of '18 from an authorized Sennheiser dealer for $1500 shipped to CONUS as I've let my HD800S headphones go. In a world with unlimited funds, I'd hang on to this gem indefinitely, but alas, I do not dwell in such a land. Here's a link...

My HDV820 was the perfect mate for my 800S's. I auditioned Woo Audio Fireflies (terrible pairing), a Grace SDAC / THXAAA789 combo (a bit better), and even plugged them into the Marantz receivers I had at home. HDV820 was exactly what the doctor ordered for me. Sold my HD800S's just last week...

An Easter Egg for you all ...

:thumbsup: Apologies, I did misunderstand your post -- you are certainly right that native 256 is a limitation of DoP with this amp. As far as the HD800S / HDV820 pairing, I'd like to echo your sentiment; I have not auditioned some of the even more expensive headphone / amp combos in the world...

I hope you got your answer already :nerd:, but serving DSD files to the HDV820 via a software program via the DoP protocol is as good as native in every way from what I understand. The DSD file is just wrapped in a different container that's unpacked at the HDV with the original DSD file inside...