"as a clue, if you see a device that has fixed and variable outputs, then the volume control being implemented is most likely analog."
I disagree with this statement. As a percentage of CDPs and DACs with volume control (I don't know of any that do not offer both fixed and variable output when they do offer volume control internally) very few are actually analog volume controls.
Of the several that I have owned, Wadia (two different units), Esoteric (one unit w/ volume control, 2 unit without volume control), DCS, Audio Aero, Resolution Audio and Mark Levinson. The Levinson, DCS (if I remember correctly) and the AA had analog volume controls. The Logitech Duet that I own has a digital volume control. I can only think of a small handful of digital devices that have analog volume controls vs. digital volume controls.
But back to the key point. I am quite satisfied with my Esoteric SA-50's digital volume control 90% of the time. Due to the gain of it combined with my amplifier, I have to play it at the upper end of its range. In fact, even at 100% I feel I would be happy with a little more volume in some music. My problem only comes when I am listening to music more softly. But in reality, when this is the case, I am not critically listening anyway - so it sort of becomes a mute point.
For the record, I find this to be the case with analog volume controls (whether via the digital device or a regular preamp). If I am playing music softly, it is more likely just for the enjoyment of having music playing vs. critical listening.
So perhaps, if the OP is like me in terms of the sound volume levels, his concerns may be less of a real world issue, making this point mute (pun intended) to some degree.
