Quite a predicament with your headphones, well I'm (going to be) running my I+ from a DAC_II
If you really want that k70x go for it!
2 in one? I didn't see that, have you tried doing a two in one inside the LD I+ before?
I'm still new to OPA swapping so you'll have to forgive my noobiness if this is quite common.
What do you get from two OPA's in one other than having to boost the gain?
And...the fake test would be whether they sound good or not?