[bose301s]

Looking for a good portable DAC/Amp to use for Android, I have a OnePlus One and that would be probably be the primary source although my 160GB iPod Classic may be used just as much. This is mainly for using on a trip to Seattle for work then Italy for vacation so I want to stay relatively cheap, the $130 limit is because i see the Fiio and Sound Blaster E3 at that price and they both look to be very good quality. I am also looking closely at the Fiio E7K as that's at a much better price and the iBasso D-Zero as the small size would be quite nice. To be 100% honest though the Sound Blaster has caught my eye the most and I am just wondering if it's worth it over the E7K or if any of the listed or non listed are just that much better than the others. Thanks in advance.

 

[estreeter]

http://www.fiio.net/en/products/38
 
Happy with mine, from a variety of sources. You'll need an OTG cable for the Android phone, but I assume you know that - the Classic will limit you to amp-only usage via a LOD (or double-amping if that's your preference). Unfortunately, I've never heard any of the other options you've listed. 

 

[bose301s]

With the iPod I'd use it to amp, I'd set the iPod volume to maybe 50% and feed it to the line in on the amp and let the amp do the heavy lifting of driving the headphones.