Hi! So uh, I bought a second hand FiiO E10K/Olympus 2 a couple of days ago. It's great and I quite like being able to beef up my laptop's audio using it - however what I had actually wanted was a portable headphone amp. Don't get me wrong, the O2 is plenty portable (it's super small!) but what that actually means in this context is that I'd like an amp I can use to give my DAP (currently a Shanling M3s) some extra juice! What I'm looking for is ideally something a similar size to the M3s that I can stack with it. Gain switch and/or bass boost switch recommended. I'm not sure how much I'm willing to spend but let's just say I won't be able to afford a Chord Mojo any time soon. That's the kind of size that'd work well for me, but it's also something like $500. If I can get something for maybe 20% of that that would fit my needs. Maybe $125/€105 is my limit - any help would be greatly appreciated Thanks HF!