Sennheiser HD800: What type of amp do I need?, [was “HD800 Amp query?”/TOS #6] Options

[GSARider]

Hi all, came across the site and thought I'd join up. Based in the UK and have been getting into Headphones more & more due to more travel by train as well as the fact that my wife doesn't like me blasting music of an evening...

Anyhow, I've got a set of HD800's arriving in the new year at a really good price via a friend who is getting them for me at a wholesale rate. I've always bought Senn's as they've always been reliable and give decent sound. I recently bought a set of Amperiors and love them for travelling. I bought a Fiio E17 followed by an e09K for use at home with my MacBook Pro Retina plugged in via optical cable.

Now having looked at various reviews / sites I'm getting more confused as folk keep saying you need a 2k plus amp to drive the Hd800's and that they're somehow 'picky' when it comes to amp / dacs?

I use the E17 on a daily basis and love the sound it gives me , not sure that the E09K makes much difference for me with the Amperiors or a set of Ie80's that I also have, but I was putting that down to the low impedance of the headphones ...would I be correct in this?