I know your not in the UK, but if you are solely a headphone listener, instead of an amp, maybe try a Chord Hugo 2. They are priced at £1800 UK pounds, but you can get them for £1500 or slightly lower. I had one and it sounded magical when teamed up with a pair of HD800S, as I had both and they both blew me away due to the sound quality.
You are from Qatar, so you must be rich and can afford to buy a Hugo 2, that beats any third party amp if you only use headphones when listening to music. Also there are a couple of new addons for Hugo 2, 2go is one of them and it's a server of sorts.
Trust me when I say that Hugo 2 and HD800S sound magical and, if you can afford it, you won't look back. The sound quality is ten out of ten.
I should add that I'm not sure what version of the HD800 that you have, if it's the HD800S, in my opinion, they don't have the peak that the earlier HD800 suffered from, but YMMV.
If you solely listen to music with headphones on, which I do and in my opinion, there is nothing that can compete with that setup price wise.