Audio ADC voltage level SNR question
Why use a 5 volt ADC range?

The fewer circuits, the cleaner the digitization results

The fundamental noise floor is the sqrt(KT/C); a large large sample-hold capacitor thus sets the floor; yes, the comparator (in the ADC) also contributes; any opamps used in a oversampling ADC also contribute.


Often any precision amplification is achieved using Cin/Cfb ratios in switched-cap opamp circuits. Given the large areas needed for low-noise amplification, the ADC designers (and marketing and Apps engineers) may decide to use ALL that capacitance in the ADC sample-hold and in any binary-weighted feedback DACs, etc.