1, Powered by USB or Battery, you can use the headphone and charging battery at same time. (When you goes outside. Use the power bank to powered it. Make it work for longer time),
2, Use lot HiFi components in this version. DALE resistors, Nichicon cap, ALPS Potentiometer, gold interface.and re-design the PCB. Make it work better.and use good-looking metal case. You will like it.
. 3, Use dual-tube in this headphone amp tube mode is: 5899, OP chip is original TI NE5532, you also can upgrade it to other better OP chip.
4, Match for 32 ~ 600 ohm headphone, work time: about 3 hours. (Charging time: about 2 hours)
1x headphone amlifier.
1x USB cable (charge cable
1x 3.5 to 3.5 audio cable