James/Joe, if it's not too much to ask, I hope a future firmware upgrade will have an option for
'USB charging mode = On/Off' just like the ones on the E17, so if you're using it as DAC, you won't stress the battery. I know the battery is lithium and it's
smart enough not to be overcharged but still for some people it is a very important feature and I believe X5 will really benefit from it in the long run. For me it was one of the greatest option provided. The user decides if the device should be charged when it is connected to a USB port. And if the power runs out, the option is automatically turned on just like the E17. Thanks! Can't wait to hear it in person!!