Why didn't you update the firmware via Fiio Control?

Do you think the power supply will be better than from a regular PD? Can you hear that?

PL50 cannot be used with Q15. Max 9v for Q15.

At high volume, the USB power supply is not enough, and the Q15 starts using the battery as well. It's just not clear if it sums up the power supply, or completely switches to the battery. Use additional power through the second USB input.

I can't find the instructions for installing the firmware on Q15. How safe is it? In the forum, one wrote that he received a brick after installation.

Thank you. I have used 1.59 firmware so far, I will flash on 1.66. As for MQA. Do I understand correctly, the blue dot is MQA Studio?

Unfortunately, the battery sometimes starts to run out, and sometimes it gets charged. It seems that there is not enough power from the USB port of the PC, when using Super high gain. Or it just doesn't work quite right.

Yes. https://forum.fiio.com/note/showNoteContent.do?id=202105191527366657910&tid=17

As I understand it, when the desktop mode is turned on, the Q15 should not charge and discharge the battery. However, today, after five days of use, when working on a PC, it started charging. I turned it off, flipped the desktop mode switch, and now it doesn't seem to charge the battery when...