I did search again for the stuttering playback and found that topic
There’s something funny happening with the DAC, the iFi iPower X, the USB ports, the current and the high frequency noises. When i disconnect the iPower X and switch to another USB port, the stutter seems to be eliminated. But, when there’s playback happening and I lock the macOS, the stutter comes back. When I unlock it, the stutter goes away. Now, if I reconnect the iPower X there’s no stuttering playback until something changes the power to the macbook or the docking station.
I really can’t keep up with that kind of issues. I’ve never had a similar issue with any hardware. So, I’m about to give it up with the iFi gear.