We are testing ADA1961 for the first time.
The issue is that at the output of ADAU1961 we have a rather high hiss noise, which is only affected by the output mixer volume. When switching off either ADC or DACs, the noise is still there. When setting down the output volume, the noise is reduced accordingly.
The same noise is on both outputs LOUTP/N and ROUT/N
HPF filter in ADC control R19 is enabled