Mini Headphone Amp : 7 Steps (with Pictures) Instructables New Amp from HeadAmp GS X Mini Headphone Reviews and Discussion Nady Axehead Mini Headphone Guitar Amp (pack of 1 Ea) Bravo Audio Headplug Mini Rechargeable Guitar Headphone Amp 100 mW New Amp from HeadAmp GS X Mini Headphone Reviews and Discussion. Package: 1 Ea Mini guitar headphone amp Plugs directly into guitar or bass for instant pro sounding audio Built in amp simulation Up to 15 hours play time with convenient built in Li Ion rechargeable battery Includes headphone splitter for 3. 5mm mini plugs, 5ft 3. 5mm to 3. 5mm stereo audio cable for connecting to aux music source & USB to mini USB charging cable