MiccaOriGen G2 High Resolution USB DAC and Preamplifier - 24-Bit/192kHz PCM

How do I use this with an iPhone ?

Can these drive HD 6xx's with ease?

Can this be used as a dac only? i have this unit, which is great btw, but want to purchase the magni 3 as well. can i use them both?

Difference between the G2 and the origen+?