Hum or buzz in the audio

First check whether the noise affects both streaming and the wired output.

1. If the turntable has a signal-ground wire, connect it as its manufacturer recommends to the phono preamp or amplifier’s ground terminal.
2. Check the RCA connections and keep signal cables away from chargers and mains cables.
3. Try a known-good suitable USB power supply. If practical, power the audio equipment from the same correctly rated power strip without overloading it.
4. Compare wireless playback with the wired output. Note whether the noise changes when the source is paused or a signal cable is disconnected with volume lowered.

Never remove a mains earth connection or open a power supply. If the noise remains, tell support the source, preamp, amplifier and charger models and which outputs are affected.