Problem with DAC volume controls is they are either digital, and sound lifeless and flat, or they are a budget/space restricted analog volume control jammed into the DAC as an afterthought.
That's why a good pre-amp always sounds better. But I would prefer one less box, not to mention one less expensive power cable and interconnect.
So I have high hopes for the new LEEDH Processing, digital volume that is truly lossless. Instead of infinite fractions used to meet specific DB steps, it used whole numbers only. So far only Soulution (way out my price range) and Lumin (much more reasonable) are using it. All reports say it competes well with dedicated pre-amps.
It would be great to see LEEDH filter down to the 2-4k DAC market.