I have received my Minibox e+ after a battery failure.
I have been using ii together with either a nano 3g or with an RWA iMod.
These OK1s are something else!!!
The PK1s, IMHO, have nothing to do against these beasts.
That does not mean that the PK1s are a bad phone at all but the power and scenario that the OK1s create is just something else.
By analogy I would pair the PK1s with the Etys ER4P/S and the OK1s withe the Triple Fi 10 Pro.
I do not understand how they say that OK1s are more analytical or delicate than PK1s.
To my ears OK1s are really powerful yet analytical and delicate with lots of controlled bass.
I will compare them with the Etys ER4/p-s, Triple Fi 10 pro, e500, SAE, PK1s, OK1s and may with RS1, Senn 650, Senn 600, and AKG 701s.
I can tell you something: OK1s are the phones that I use more often.
The Minibox e+ drives them with authority.
Regards