Pros: Tiny, excellent build quality, custom leather case, digital volume control
HeadAmp pico Slim Portable Amp Reviews
Pros: extremely small but amazing sq. volume control is excellent
Cons: not for full sized HP
Pros: Tiny, excellent build quality, volume control is excellent, sound is grain-free, charges off USB and the battery life is long.
Cons: Not suited to cables with large plugs. Designed for IEMs only.
Pros: very small, sound clear
Cons: peak at powering on
Pros: Digital Volume Control! size, battery life, sound quality and build quality of course!
Cons: Wow - Pricy!