Impulse
500+ Head-Fier
A media player is essentially both things in one too (usually a poor amp but there's still varying degrees and it depends on the headphones etc). A DAC can be a straight stereo DAC (like most USB DAC) but it can also be a processor that does different things to the signal (like a Mixamp, sound card, etc)... Although at that point we're diluting the meaning of the acronym to an extent, I guess technically there's a DAC in those devices plus other DSP functions (digital signal processing).
What would you be using the E17/E09 with, a PC? You don't have to use the optical in, you could just use USB... I believe that's what the USB pass thru on the back of the E09 is for, powering the E17 and/or hooking it up to your computer.
What would you be using the E17/E09 with, a PC? You don't have to use the optical in, you could just use USB... I believe that's what the USB pass thru on the back of the E09 is for, powering the E17 and/or hooking it up to your computer.