Flexible DAC or Preamp or Integarted for Headphones Seeking Recommendations

I have built my current system around pieces of gear that are flexible in that they can serve multiple functions in a system, depending upon my likes. Some examples of the gear that I have now include:

• LTA MicroZotl MZ2 which I use as the preamp in my main system, but is flexible to be used as an integrated and/or a headphone amp.

• BlueSound Node 2i which I use as a dac/streamer in my main system, but is flexible as a stand alone streamer into an external DAC.
• Rogue Audio Sphinx which I use an an integrated in my second system, but is flexible as a preamp as well.

With that in mind, I am looking for gear to use in a headphone setup in a new desktop system. I understand that I could use the Microzotl for this, but I enjoy it so much in my main rig that I would like to keep it there.

So I am looking for a flexible piece of gear to drive my Drop 6XX headphones. I am entertaining the following right now:

• Ayre Codex
• Mytek Liberty

I have heard that both of these are great DACs with good headphone capabilities and both are flexible to use as standalone DACs in a speaker setup.

Does anyone have gear recommendations along these lines? A DAC with a good headphone stage? A preamp or integrated with a great headphone stage?
As always I really appreciate feedback I always receive from everyone on this site.