That chip claims the noise is -90dB, which is not particularly low-noise. You may have fairly sensitive speakers making the problem worse. I make that 250µV rms noise on the output.
Its possible that pcb has high value resistors on the input making the noise worse, but without a circuit diagram its hard to know.
Its possible that pcb has high value resistors on the input making the noise worse, but without a circuit diagram its hard to know.