Does the MR816 CSX provide a sufficient output voltage, so that with a 600 Ohm impedance headphones connected it can provide an output power of minimum 50 mW at this load?
Shorter to say can it drive a 600ohm beyerdynamic dt-880 ?
My old AKG K240DF are 600 ohm, and they’re OK. My Sennheiser HD600s are 300 ohms are fine as well. They get louder than I can certainly stand (though, admittedly, I’m not into the face melt)
If I remember right the max output impedance of the phones socket is 80ohms, meaning you’ll get better performance from headphones of approx 480ohms or less before the need for an independent headphone amp.