I think 2StepDance may be the best portable amp I own now. It transformed iPod 5G from a source I thought was just above Clip+ to something I could put on par, if not a little ahead of my QA350 -> UHA-6S rig. I listened using EX-1000 normally - a few weeks back (2nd week of Jan) with DacMini, yesterday with I2S and today with BS. So, it's not exactly a one on one comparison, rather a collection of thoughts on what stood out for me.
Now that I have three rigs which took a heavy bite of the wallet, it's interesting that all three have some uniqueness. As of now there is no clear winner in my mind. Ex-shipping and Cables, DacMini CX is in the range of $800 new (though less than $700 for me), QA350 brick stack (QA350 Mod V2 -> UHA6S,
BS for short) is about $530 - though only the $280 of UHA6S matters here since QA350 just acts as a transport, iPod rig (iPod Video 5G 80GB -> 2StepDance,
I2S for short) was cheaper at ~ $500 largely because of the older iPod 5G. In short, a $800 Desktop Dac-Amp against a sub-$300 portable Dac-Amp and a $500 transportable source-amp rig. Contrary to what the price range indicates, I cannot say that Dacmini was in an entirely different league, just different in it's approach.
2SD produces a much clearer sound with a darker background than BS. The balance is very even across the spectrum. Treble feels like it has much better extension (which I cannot verify with these rolled off ears), but it does have much better sparkle and presence. The mid range is more clean sounding, slightly thinner, bass has slightly better punch. Going back to UHA-6S, I thought I had lost the sharpness in each note and sound stage seemed more cohesive than the well separated presentation of 2SD. The sound stage size did not seem too different (May be 2SD is a little bigger). But, where UHA-6S scored was in bringing forth more emotion and intimacy - in my case, the death growls of Akerfledt were much more special with the UHA-6S like you can hear every bit of his throat movement. Especially around 3:15 in "Advent" (
Where even foes close their eyes and leave), the closing part of 'Leave' ripples from back to the front which I do not hear / feel with other sources (just more deep bass?
). It was a bit more relaxing to listen to with the same album ("Morningrise") due to the smoothness of the sound. However, guitars benefited from a relatively clearer and sharper note presentation of 2SD (crunchier). I am not sure why, but I felt that UHA-6S had great layering and imaging a few times, but I2S felt more matter of fact when indeed both may not have done anything hugely different with the same IEM.
Coming to DacMini CX, it felt
relatively more analog due to good body and weight to the sound. DacMini has perhaps the warmest mid range among the three. I did not think that the sound stage was great on the CX. It is again a bit more intimate in presentation like UHA-6S and could be as fatigue free as UHA-6S at the very least. Otherwise, I'd not have listened that long into the night.
I2S rig comes off as neutral and detailed presenting a very sharp picture of music with good separation and clarity.
UHA-6S is slightly more focused on mids followed by bass compared to treble and more cohesive in presentation.
DacMini paints a richer presentation of the music among the three. It may have a similar FR as I2S, but also has a more fluid sound. I suspect it may come across as the better source of the three except for sound stage.