[Malfunkt]

Good post post! This is probably all you need, it's what I would try!

http://www.amazon.co.uk/Epiphany-Acoustics-EHP-O2-Headphone-Amplifier-Black/dp/B00G2DK52W

Thanks Jonone, I have been looking at the 02 variants out there (JDS Labs) as well as the Schiit Magni. But yes, this looks good especially with switchable gain settings. 

 

[Jonone]

I think this might actually be better as its for desk top http://www.amazon.co.uk/Epiphany-Acoustics-EHP-O2D-Headphone-Amplifier-Black/dp/B00G35A2AO/ref=sr_1_2?s=electronics&ie=UTF8&qid=1406492763&sr=1-2&keywords=O2+amp

Let us know what you try!

 

[Jonone]

I've got the jvc dx1000 now and I like them, as I've posted elsewhere compared to the d600 the mids are fuller and more forward and the treble is smooth and very un-fatiguing, the down sides are there ridiculously BIG and the cable is stiff and ridiculously long, also there's 1/4" jack on the end so I need to use an adapter for the ipad.
Another reservation is the level of bass it's very tight and clean and seems to go as deep as the d600, its not as loud but probably more accurate, I also think its slightly flatter/dipped in mid bass which gives that feel,I'm sure you could eq it to the level of the d600 and have the best of both worlds.
The sound is very light and airy and has what I can only discribed as an "audiophile " feel, they make the d600 sound very smiley faced in signature and thin/ harsh.
I would like to compare them to the hd650 I would think there more similar then not, I would imagine the hd650 has more midbass punch but less sub bass, it may also be slightly less forward in the midrange?

 

[Malfunkt]

I've got the jvc dx1000 now and I like them, as I've posted elsewhere compared to the d600 the mids are fuller and more forward and the treble is smooth and very un-fatiguing, the down sides are there ridiculously BIG and the cable is stiff and ridiculously long, also there's 1/4" jack on the end so I need to use an adapter for the ipad.
Another reservation is the level of bass it's very tight and clean and seems to go as deep as the d600, its not as loud but probably more accurate, I also think its slightly flatter/dipped in mid bass which gives that feel,I'm sure you could eq it to the level of the d600 and have the best of both worlds.
The sound is very light and airy and has what I can only discribed as an "audiophile " feel, they make the d600 sound very smiley faced in signature and thin/ harsh.
I would like to compare them to the hd650 I would think there more similar then not, I would imagine the hd650 has more midbass punch but less sub bass, it may also be slightly less forward in the midrange?

The Denon AH-D600 is an odd one. It has got plenty of listening time out of my cans but more and more that smiley face signature is starting to become a bit tired. Perhaps I need to give a break.

Coming from the HD650 and recently acquired MDR-7550, the D600 does sound harsh and kind of wonky. It's amazing how your mind gets used to a certain sound. Now I realize that the 7550 and 650 have their own sonic imprint, but ithey are much more faithful and tonally accurate to the source.