Question about Bose SoundLink Mini II

You can connect the speakers to your iMac either via AUX cable or Bluetooth.

I have two completely different opinions about this device:
1:) the sound quality and design are exceptionally good +++++
2:) the electronics have a development error, which is noticeable as follows: when the unit is connected to the PC and the unit is normally 'on', everything works without problems. If you now shut down the PC, the active suppression of the 50Hz signal by the sound card disappears (because the PC is switched off), the SoundLink Mini II does not notice this and amplifies the signal until only the loud 50Hz hum (from the mains) drowns out everything !!!!!!!!. I have already connected the SounLink II Mini to various devices, including the stereo system, and the same thing always happens: when the stereo system is switched off, the SoundLink Mini II hums loudly. For this reason, I returned the device to Digitec, despite the good sound and good design. There is probably a product development error here that the developers have not noticed.