Portable DSD/DAC Headphone Amp for iPhone?

I have Sennheiser HD800 and Beyerdynamic Amiron headphones. What is your recommendation for the best combo DSD/DAC headphone amp out there? I want use my iPhone X as my hi res DSD playback device using the currently installed Onkyo HF Player app. It plays DSD ( .DFF and .DSF) files.  * Must be able to convert at native DSD or hi res PCM (96 /24 or higher) resolution. * Must be truly portable. Ie. Battery powered/chargeable. 
Is there such a plug and play portable converter amp? If so what’s the cat’s meow? Money no object. 


These are both excellent replies... thank you both! I’ll do some more research and report back here!
As a consumer I felt when auditioning head-fi DAC/amps that Chord was overpriced when compared to similar from iFi Audio...
I am a Chord Dealer and Chord makes a couple devices.

For a very good Solution:  

The Mojo is a wonderful portable DAC.  You can connect directly to it with the Apple Camera connector and then plug a USB into it.  The Mojo is $499 and i think the adapter from apple is $99.  

You can also add the Poly to it and stream to it via Airplay or Bluetooth A2DP at redbook resolution.  If you are on a wireless network, you could stream full resolution via WiFi.  The Poly is $649.

For an amazing solution:

The Hugo 2 is the way to go.  Also completely portable and you would need the same apple camera adapter.  It is a spectacular DAC with unbelievable quality.  The Hugo 2 is $2495.  

You can also add a 2Go which is a streamer like the Poly. Wifi, Airplay, DLNA, Roon Ready, etc... just like the Poly.  The 2Go is $1295.

There are carrying cases for both units.  

PM me if you want to discuss more or you can order direct from me at www.artaudio.us.  I am sure there are other options on the market but either of these meets your needs I think.