In traditional pure-analog designs, a switch resistor network for volume control works best but is very expensive due to the use of many high precision discrete resistors. Next is a high-quality volume pot. You rotate the pot to change the resistance, which in turn attenuates the volume. A volume pot is non-linear and has balance issues at low volume. Some DACs do not have built-in volume controls and you therefore have no choice but to change volume at the analog output. We try to avoid that. Fortunately the top DAC chips have volume controls, which make sense since it’s best to adjust the volume in the digital domain for digital signals
Our DAC-9 ($749) and DAC-10 ($1495) have analog inputs without A-to-D conversion. We use a mixed analog and digital volume-control design. The digital volume control’s 0.5db steps are sent to the DAC for the best possible result. The DAC’s analog output and analog inputs from other sources then go through a switch- resistor network. The DAC's output is switched straight through with minimum resistance. For analog inputs, the switch resistor network provides the best possible result. The digital volume control from the front panel manages switching the analog resistor network.
In conclusion, we feel we’ve developed the best type of volume control and preamp for a modern DAC.