Sony XA7ES headphone section

How good is the headphone section of Sony XA7ES? Do I need to get a headphone amp to drive the Sennheiser HD600?
I have both. The Sony seems to do a good job of driving the 600's, but I've nevered used a headphone amp, so I don't know how it would compare.
I too had both. I found the headphone section og the XA7ES to be o.k. at best and would recomment one of the better headroom amps for the job.