As a hud-mx1 owner I am anxiously awaiting the first reviews of this new unit. I am on the fenc. about upgrading.
For the price point, I felt the original hud-mx1 was a great value and perfectly suited the requirements of my particular application. That being, to drive a pair of mid/low end studio monitors via RCA jack from a windows PC on a secondary rig. The volume attenuation of the rear RCA's was a critical "convienience" and solution to my needs. Requiring attenuation of the line out seriously narrowed the pool of viable candidates for my selection at the time.
In regards to fidelity, the hud-mx1 was equally well matched to my application. My extremely limited testing of the MX-1 in it's presumably intended application (as a headphone amplifier) leads me to believe that, while adequate, most serious head-fi'ers would scoff.
I have, however, experienced issues which have grown from a nuisance to mild annoyances in two years of otherwise pleasant ownership. It would appear that these issues are all addressed in this new iteration-the HUD-MX2. The issues were:
#3. I was hoping to be able to experiment with hosting the HUD-mx1 from my Samsung GS3 when I got back when they came out. Although I am not sure what the realities of using an android phone as source are, it was a novelty I hope to at least explore. The hud-mx1 isn't capable, the hud-mx2 apparently is. My guess says the problem lies with the power architecture of the Mx-1. I believe the dac circuit relies on USB power even when optional DC is supplied via rear connector. In my non-expert opinon, it is a design shortcoming because USB power is too noisy (and scarce) and should be completely severed when auxiliary power is available. I have no specific knowledge of bus specification or covention, so this is speculative. However, it is supposedly resolved and the whole circuit is improved
#2. The volume knob on the MX-1 is awkward, but worse, the volume pot has become VERY "scratchy" . I have used it much more than I would say a headphone user would, but nonetheless it is unacceptable.
#1. "Popping" when restarting or powering up the PC is bad on the MX-1. Supposedly fixed on the Mx-2. Since I am driving almost 600watts of live amplifier, this issue alone, over time, has me fed up. I am tired of powering the monitors on and off to prevent this. Again, supposedly fixed. I hope reviewers of the Mx-2 will evaluate this.