Hello gentleman. Recently I’ve purchased this wonderful XD05 Plus. Mostly I listen to music from digital signal delivered over USB cable. I wonder if it is ok to have a second USB cable plugged in at the same time to charge the battery. The cable would have to supply energy for the amplifier while maintaining the battery at full charge. In your user guide you do not specifically discourage this practice. Was the unit designed to be operated this way or is it harmful for the battery? Do I have to stick to standard charge-discharge cycles? Thank you.