Hi all, I've had this unit for a year now. Quick review: is good. 'Punchy' sounding if that indeed has anything to do with the DAC/AMP. Headphone out is weak if you have anything demanding, though. Don't bother with planars or 300+ impedience headphones (with few exceptions). Just don't. And no, you can't line out to a better amp. You'll need another DAC/AMP. This is almost an Achilles heel for demanding headphones listeners unless they want to source a separate DAC/AMP.
I've read about the USB issues with the device and switched to optical. I wasn't sure whether I should expect a difference, but while I can't say for certain whether it sounds better, in my case, it is much louder. Too loud. I went from a USB port on my PC to its TOSLINK out, and noted immediately that it was much louder at every gain level. I plugged in my most demanding cans (these old, weird AKG K340 hybrid electrostatics) and while I could drive them louder, above mid-upper 40s the distortion was obvious, like really obvious.
Something is boosting the signal...? On my PC, the output is 'Realtec Digital Output.' I looked at its settings in W10 to see if it was boosted, but didn't see anything obvious. Does anyone know what the deal might be?
I'm honestly about to sell the thing. It is good, again, but it falls short in a few areas for my use scenario that have made it officially annoying for my setup.
Edit: if this is happening with other people's setups and they're not noticing, that would immediately make the audio sound better (because louder music sounds better, generally, up to a point of course). It is easy to A/B with this device, and adjusting for volume, I can't personally pick out a major qualitative difference in quality between the USB and optical. I went back and forth over the same piece of music several times. I think it is volume related/placebo; my rule is that if you are straining to hear a difference, there isn't one, subjectively, and you're more liable to psyche yourself out.