Is the fiio x3ii enough to drive the hifiman he400se? What about e07k? And what about a dongle?

Is there any way to repair an iem driver? I have an aurisonics asg-1 plus and the left bud plays at a way lower volume than the right one. Is there anything I can do to salvage it? I've tried everything, from sucking on it, cleaning it with isopropyl alcohol, to open it, switching one for the other etc. I can't really describe it with audiophile terms, so the only thing I can say it is that one is at a lower volume than the other.