According to Audeze it's stereo only for ps4

so those sony playstation headsets are simulating surround from stereo source?
Always thought the headsets had proper surround (never tried them myself, though)

yes, it will process surround from the optical connection.

I'm using the GameDac myself, paired with a Sennheiser HD598, works very well...Play Rainbow 6, Titanfall 2 with it, love the surround.

It isn't particularly powerful though, as it won't provide enough power to use my Hifiman HE400s (Sound is damn low vs the HD598 which is much much louder)

never bought.
ps3 time was not using headphone, was just using speakers and bluetooth earpiece for chat

I think my A50 I bought after the PS4 came out

yeah, wired headsets only.
i suppose theoretically you could plug in a 3.5mm ended bluetooth transmitter and convert the gamedac into a wireless one, but you'd most probably lose out on the surround as I don't think bluetooth supports surround.