I have a AK100 with RWAK mod. iPhone5 has low impedance output. Maybe it's because of poor workmanship. One earphone shorter than the other, the left ear strongly presses the outer side, a second very short and does not provide good seal while I move. It's a bad, because the ear impressions were made not for the first time and I know how to behave with it.
What's more surprising is frozen fingerprints on the shell. Great quality, guys! :D
Put the stock cable back and maybe you'll understand that they are just very revealing of what you do in front of them.