Currently using an Iphone 6 plus. I've decided to go back to an android that can use v4a. I want to be able to listen to Spotify/Tidal and maybe some podcasts while running. I've been using my old Note 2 recently, but it's too heavy. Thanks.

I've enjoyed my time with the Note 2 as an audio player (Poweramp).  It sounds good, but it does need more volume.  Already boosted the volume through a custom rom.   So I'm thinking either...   1.  Upgrade to an HTC M8 for $350ish used   2.  Keep the Note 2 and buy an amp like the E18 for...