[aiolos65]

The Beyerdynamic T1 has power handling capacity of 300mW .......The Oppo HA-1 in the balanced output delivers 800 mW @ 600 Ohms so if i recable my T1's with 4-pin XLR connector and use the
Oppo HA-1 in balanced mode i will damage my headphones???? I don't have the Oppo HA-1 but i am thinking to buy this dac/amp and recable my T1's.

 

[Me x3]

No.
In real life you only use just a few mW to drive a T1 at normal levels.

The amp is capable of enough power to damage the headphone, yes... but you won't raise the volume that much.