In that range, my list would include:
Dan Clark Audio Ether (great sound and much lighter and more comfortable than Audeze, in my opinion of course)
Sennheiser HD800S, also very comfortable
HiFiMan Arya
Focal Clear

The Dan Clark Audio Ether looks like a viable option.

So what headphone amps would I need to look at?

I would recommend the Stax Electrostatic Amps. I use the Stax SRM-T8000 and also the Blue Hawaii.

Will second this. The Clear have a better overall tonal balance for a wide range of music, as well.
But, the Stax that Ivan recommends are also very close to the Clear in SQ, though not as comfortable on my head for long-term listening, which, of course, is very much an individual thing.

Thanks for the info.

I don't see a STAX forum here :scratch2:

Nope, really not that much interest in them; unfortunately. :sigh: