Aune X1 Pro DSD DAC/Amp

I’m curious about this as well (5 years later), as running a pair of Grado Sr80e does sound pretty bright through this amp. That recommended impedance range for headphones of 32-600 would suggest that the actual output impedance is not nominal (less than 1 ohm). I’d bet it’s in the 4 ohm range, as I believe recommended headphone impedance matching is generally considered to be at least 8x output impedance. So the recommended minimum headphone impedance for a 10ohm output would be ~ 80 ohms. Lots of studio monitors like AKGs won’t show any frequency response anomalies, but low impedance IEMs probably would. I think my Grados are around 30ohms, and they are bright sounding anyway. But the impedance matching may not be helping.

So did you get your answer?

I've had this DAC/headphone amp for a few years now and it has worked flawlessly. It sounds good too, and the volume-controlled variable RCA outputs is very useful for use with powered speakers. Honestly, I doubt many people could hear the difference between DACs in a blind A/B/X comparison, especially with anything less than world class headphones or monitors.