Audiophilepure

https://www.whathifi.com/us/reviews/warwick-acoustics-sonoma-model-one

You’ll need to be a little careful if you’re using the analogue inputs. Both have specified upper signal limits – the RCA will take 2.1v while the 3.5mm jack is limited to 0.85v – and if you go beyond these it’s possible to overload the circuit, though the only consequence is likely to be distorted sound rather than any real damage. If you need to use analogue it’s probably best to use a source that has a volume control built-in so you can turn down the signal level if the energizer has any issues.

All input signals are handled in the digital domain, so any analogue input is converted before any other processing is done. This conversion is done by a 32-bit/384kHz AKM Premium ADC, which is claimed to have a signal to noise ratio in excess of 120dB. There’s a good deal of signal processing done in the box with the aim of accounting for the headphones electrical characteristics and so getting the optimum sound possible”