Control volume with DAC or Preamp?

Only if the DAC has an a proper analog line pre stage. Volume control via DAC chip is to be avoided period. In generally a high quality separate pre will always be better.

The OP's is not passive you are right but in the thread above you will see GeorgeHifi comments about " Ralph is product (his active preamp) " etc. and for some reason (and I have nothing against GeorgeHifi) he has some feud with Ralph, he even quotes Ralph's phrases " This statement is false," so the thread deviated into this arena ...

@madavid, why should ...”Volume control via DAC chip is to be avoided period.”...?

I’m not sure that one could accurately describe the OP’s direct from DAC to amp application as “passive”?

@unsound Check my original post in this thread.

@atmasphere, My previous post was in regard to your more recent post and newly mentioned “passive controls” and whether or not that was indeed the OP’s subject at hand.
 In response to that original post, I think it prudent to mention that depending upon the partnering amplification, some DAC’s have many more bits available to handle volume control with little to no risk of bit stripping for even 24 bit hi rez formats.