[vahid1234]

I am looking to buy the Beyerdynamic DT770 premium edition, i will be running them off the audiophile DAP the hisoundaudio rocoo p 
i don't know which impedance would sound best with the player, 250 ohms or 600 ohms?

 

[kore]

You will need a dac/amp for such ohm...

 

[vahid1234]

what portable amp would you recommend? something fro the fiio line? i dont know anything about portable amps

 

[Canadian411]

Get anything but 600 ohm, especially you are not planning to upgrade balanced cable.

I had beyrdynamic DT990 600ohm premium and my SR71b couldn't drive properly.