MA352 Headphone out + Meze Empyrean

Hello,

I just got a McIntosh MA352 from a retailer, sealed, new. It was in stock so I took it in but I don’t have speakers yet, as they will be delivered in two weeks time. 

I decided to try my new amp, and pro and proceeded to hook in and use my headphones, Meze Empyrean, to see how it goes. Well, it was a total

Mess. The amount of distortion I got was insane. In disbelief I tried different songs and the same: you can hear the song but very distorted, and noisy. As if the drivers were damaged.

Immediately disconnected the headphones and went back to the headphone amp (Feliks Audio Euforia) and it was as good as always.

What could be wrong with the headphone out of the MA352? Is this caused by something related to the power needed by the Empys? I would have expected I would need to turn up the volume a lot, but never this noisy distortion. 

Any ideas?

Best.