As many are asking about how the 1A compares to the ZX2, and as an owner of the ZX1, ZX2 and now the 1A, I thought I would write my impressions.
For the purpose of my comparison I am using the AKG 3003s (although I have also compared them with my Roxannes CIEM) mainly because I consider them to be a very neutral sounding, transparent IEM, and by that I mean that it does not colour, add or subtract much to the signature of the DAP (or the recording for that matter). And while I am on the AKG subject , I think I should mention that not only do I consider the 3003s to be one of the most balanced, neutral, but at the same time rich and musical IEMs I have ever heard, but more importantly they match with all 3 Sonys very very well. It has been said many times that the match of the DAP and the IEM is at least as important as the components themselves and I would highly recommend listening to the 1A with the AKGs, the results are stunning.
Back to the ZX1, ZX2, 1A comparison:
When I first bought the ZX1, I thought it was a good but not great first try from Sony at making a hi-end DAP.
The main card it brought to the table was its resolution, with a lot of detail, and impressive instrument separation.
On the other hand, it its quest to impress with the amount of detail, I thought it was somewhat dry, lacking in richness of timbre.
It was also a bit grainy in its mids and when sound got more complicated it had trouble coping. It seemed to do better with simpler pieces of music, acoustic, voices or classical.
The ZX2 is another step forward, I would say quite audible.
Bass is improved (but sometimes can get a bit bloated), the mids are clearer and less grainy and treble is smoother in a way only very high quality components can achieve. Imaging is also improved and there is definitely a wider space that the ZX2 creates in front of the listener (I think there is a little bit of DSP effect going on there in that the sound instantly feels bigger).
But the one single difference that sets the ZX2 apart from the ZX1 is the pure fun of its sound. While the ZX1 can sound emotionless and dry sometimes the ZX2 achieves this rare effect where one gets immersed in the music in a very fun kind of way. It was the first DAP that gave me the same kind of emotional experience I get from my Focal speakers.
On to the 1A. To be honest I wasn't expecting much. I had read that it is quite neutral compared to the 1Z and probably the existence of its golden big brother made the 1A seem like a small evolution of the ZX2. My hearing impressions are that the improvement from the ZX2 to the 1A that Sony achieved is bigger that the step between the ZX1 and ZX2. And it is not in one or the other area, but in every single aspect of the sound. Its bass is, to me at least, perfect, just the right amount, never bloated, never overwhelming, always right, you hear the notes very clearly, you hear the bass, as in the organ, rather than the bass as in the frequency range if that makes any sense.
The mids are clearer than the ZX2, no grain whatsoever, very smooth and musical, effortless is the word I would use - in fact that is the word I would use for the 1A's sound overall. The treble I think has even better extension and is even smoother, never sibilant or harsh.
I believe the "Direct Sound" feature brings a new edge to the pureness of the sound here, going back and forth between ZX2 and 1A I can hear the DSP doing its thing on the ZX2, and a very natural, effortless high quality sound on the 1A, pure hi-end in my opinion. And while I have not heard the 1Z and cannot compare, regarding it's "warmer" sound as often reported, I can say that to my ears the 1A sounds just about right, the right amount of richness and depth/decay to the sound. It remains a very entertaining sound, maybe a touch less lively than the ZX2 but quite right, very enjoyable.
All of these impressions are made using the non-balanced output, so comparable.
A last word on volume.
Mine is the capped version and I can never hear it at max volume for more than 5 minutes.
I have trouble understanding all this fuss about the capped/non capped issue.
Hearing being our most precious "component" in this hobby, and the one thing we can't replace or buy, I would consider the capped version's max volume the limit of "safe" volume meaning that more than that, for long listening sessions can surely cause damage to one's hearing in the long term.
