[CommanerKeen]

I've had the card for a while with my HD555 but looking to upgrade.
Have my eyes on either HD650,DT990 600 ohm,HE400,akg 702 and suchs. But at that point,they usually need an amp to drive get the most of them.
I've read over few forums\threads that some say you need an amp,some say it's fine with the Essence.
Is the amp absolutely necessary to drive those headphones or I shouldn't botter and wait to get a proper amp before?
Thanks.

 

[StudioSound]

A quick search suggests that the output impedance is 10 ohms, so any headphones you use with it should have an impedance of 80 ohms or greater. (up to 600 ohms apparently)