It just happens that I have in my stash an old power supply (from a broken external FireWire disk) that has this very plug!
And I can confirm that it fits perfectly in the Cube socket. (I didn’t check for height clearance, an angled plug might be necessary)
The cube psu plug is definitely not a mini-din. Everything is too small in a mini din, the outer diameter, the pins, the current rating…
And if the Amphenol one is a standard din plug, I think they’re too big!
The lineup of Apple Studio Display that plugs into an ADC port includes this beast:
Rated at 113W ! (and powered exclusively through the ADC port)
Half of the power of the Cube power supply is just to power this big CRT (the last one ever produced by Apple, an incredible design imho! (just...