I bought the WiiM Ultra on 18th December and tested it for three weeks. I am using an Odyssey Audio Stratos power amplifier and have been constantly facing an issue with one channel—first the left channel and now the right. The right channel suddenly loses volume. After clearing the app cache and data and resetting the device to factory defaults, it works fine for some time, but the issue reappears. I sent the unit to the service center, where they said everything was fine. It came back after a week at the service center, but the same problem has occurred again.