by RoJeC on 22 Jan 2021, 12:52
When audiodevices 'produce' crackling sounds when no audio is playing it could be power related. As iOS device and audiodevice not likely generate problems (when not playing)
If you have multiple devices in the audio setup make sure they all use the same phase of the power (e.g same wall outlet). From source (iOS) to amp/speakers.
Other equipment may interfere. Like (LED/halogeen)dimmers, powersupplies etc.
Disconnect all chargers (if possible)
Try working without a ground connector for all connected devices (depends on country you live in if this is allowed/possible)
BTW this is for trying to find the root cause. Not a final setup. If the crackling is a 50Hz noise consider a groundloop adapter.
Might take some back and forth before finding the cause and a recommended solution.
Also try to move the audio cable away from power cables.