what in what I just said makes you think i'm FOR passive IV?
you still havent read up on Ohms law have you?
put resistance in the way of current, it turns into voltage, put resistance in the way of voltage, it turns into current....that conversion can be done passively with a simple resistor, or it can be placed at the output of a current feedback amp, discrete follower/buffer or in the feedback loop of an opamp so that the amp or active device in the active IV stage is driving the resistor to convert to voltage for your amp to amplify.
this means that the dac can be allowed to drive a very low impedance, not as hard work. its a current source remember, not the voltage source we spoke of before driving headphones, if you want current to stay current, you need to provide a low impedance
passive IV with ES9018 is Dumb, you need a really robust current source to use passive IV, even then i'm not a big fan, but with ESS you lose performance significantly, could be as much as 20dB THD lost. the ESS is a pretty wimpy current source, not low current, but not high impedance, an ideal current source has infinite impedance, es9018/12 is only 195ohms output impedance in stereo mode, so you need a REALLY low impedance
some companies still persist in using passive IV with ess, not many though
the COD is just a current out dac (PCM1794A) wit power supply, its a VERY rudimentary design, the dac is kinda just there, its a current out dac, but the 1794A has a higher (but still not that high) output impedance, so will work with passive IV better than es9018, that being said the ess will still win out, but with a lot of wasted potential.