The output voltage of our D/A Converters can be set in a few steps in the analog domain. This allows to set the output voltage such that the subsequent amplifier is properly driven.
This can be judged with the volume control potentiometer: The volume control should work in a decent range around the middle of the control range. For example, it should not be set to the start or the end of the control range to get proper loudness. So, choose the output voltage step, which allows for a “proper” volume control.
One must know that if the D/A Converter output level is too high, the amplifier input can be overloaded. The volume control in an amplifier is usually not located right at its input but somewhere in the signal path. So, the input amplifier can be overloaded even when the volume control is put down.