Amp troubles - noisy TEA2025
Conceptual Diagram Stereo single supply direct differential drive.







simulate this circuit &ndash; Schematic created using CircuitLab

Perhaps they drove the common mode with ganged channels and Left/Right with differential to avoid all the coupling capacitors.


In any case your hum is from the mobile charger so you need to suppress that with a big CM choke filter and/or earth ground.