“Whether Dan Clark Audio Stealth or Expanse, both require a high-end headphone amplifier with plenty of power like the SPL Phonitor.”
Mastering with headphones is gaining more and more importance.
At the online platform positive-feedback you can find an interesting article about mastering.
Dirk Sommer (Hifistatement) and Casten Hicking (audioNEXT) visited mastering engineer Christoph Stickel (Yello, John Williams, Die Ärzte, Seal, No Angels as well as a Star Wars soundtrack among many others) in his CSM studio in Vienna.
You can read the complete article online at positive-feedback.com.