Are there any notable differences, in sound quality, between the E18 vs E12? Or is the only difference Android v Apple? I ask because i don't use either.

Why do you suggest the Objective O2?

Sorry if i wasn't clear, i want a portable amp. I have used a my headphones with a  cheap FiiO amp and the sound IS better and it seems to me i lifts the bass up quite a bit, if there is one thing the k702 is lacking it is bass.

For a nearly half a year i have had them and been using an ASUS Xonar Essence STX sound card, however i would prefer to have an amp as the sound is better. Probelm is i have no idea about good portable amps etc, i know a little about headphones but almost nothing about amps! I have looked in...