Don't bother Man. Speaking as an AK240 owner who bought the DX90 as a 'spare' and discovered that the DX90 is an awesome DAP with neat synergy with the SE846. Don't get me wrong the AK240 is an awesome DAP. The SE846 sounds great with the Blue filter sans DX90 but plan to 'lift' it a little with the White. I think that's really going to cut it.
I'm a little confused. "Sans" usually infers "minus".
Jaben don't stock the DX90 otherwise I would have auditioned that as well. They said they would do the AK120 for $1,100 which is rather tempting.
In saying that, the bass guitar in BB King's "Why I Sing the Blues" had an almost equal quality to it via my iPhone. I think more thorough auditioning is needed before making the comitment, although 192GB on the go storage would be massive..... This is not going to be an easy decision.