I thought I should perhaps start a new thread about the NX4 DSD so as to not detract from wushuliu's excellent More Amazing DACs for Peanuts
which is more about the Sabaj DA3.
This little guy is battery powered and has the mobile ES9038 DAC chip in it. Separate USB ports for power (charging) and USB audio, which you can see in this pic:
The manufacturer's (English) webpage doesn't show up easily in google, but here it is: http://en.tpdz.net/products_detail/productId=25.html
I really like the way it sounds! This could be reverse expectation bias or honeymoon period or whatever.
However despite being shown on the webpage linked above with an iPad and iPhone, it doesn't work with them over USB. I have tried both the USB2 and USB3 CCK. At this point it seems the only option is analog in (which I haven't tried yet).
[My bad, it works great. See below.]
It does work great from my Macbook and a Raspberry Pi. I just got an OTG cable so will try that later on with Android. (I'm not sure if Android still resamples everything to 48k tho).
Not working with iOS is a disappointment, but that's not really my main use case, mostly I intended to use it as a secondary headphone listening station and the RPi will be fine for that. So while I'm a bit undecided I think I'm going to keep it anyway (heck, for the price....). I put in a query to Topping and will post if they respond.
I got mine here
, also available here
. Massdrop dropped one
a little while ago and they might come up again there.