If you get a DAC with a volume control make sure you understand if it is a digital or analog control. Digital volume controls may tend to sound compressed at lower than maximum output because they are simply scaling down the numbers. I use my DAC's digital output set at max and prefer to control the volume with a preamp. I have not tried the direct route you describe because I have other audio sources which the preamp must control.
DACs with volume controls
Okay, I love all this audiophile stuff, but I'm a private school teacher (little money). So are there any decent used or new DACs that I can purchase with a volume control and hence skip the need for the preamp? I'm thinking I can go 1.5 grand, maybe 2 if I wait till summer. Anyone out there use this stuff or heard it? I'm new to this sonic world and have only read about the Wavelength DAC, don't know any others.