If the preamp is an analog volume control, potentiometer or relay-driven voltage dividers, that would be preferable to the DACs volume control, which may be playing with bit depth to achieve that function, leaving you with less than bit-perfect audio. Set the DAC to full out or just below and use the preamp.
Control volume with DAC or Preamp?
My DAC (PS Audio Directstream) has a volume control and so does my preamp(Benchmark), of course. What’s the best way to control the volume of my system to get optimum sound...turn the dac to maximum volume and use the preamp to make adjustments , turn the preamp to maximum and use the DAC for adjustments, turn each of them up part way? Or does it not make a difference?