Why would you fixate yourself of finding an amp for Roxanne? It sounded good straight out of an iPhone 5. Even better on Hifi DAPs.
It sure is not about power which is what an amp is suppose to provide since Roxanne like any iems are very easy to drive and don't require much power.
I suggest you better look for a better DAP or source than a portable amp.
Well, I wouldn't say that I'm fixating on finding an amp. Really, it was just a question to see what folks were using. And I'm pretty happy with my AK240 as a DAP. Again, innocent curiosity. Different strokes and all...