OK,
I have had my AK380 for about a month now and its time to post some impressions.
Before I had the AK380 I had an NW-ZX2 for 6 months, an AK240 for nearly two years and the AK120 before that, so yes, I like the A&K players.
I have been listening at least 4 hours a day at least 4 days a week since I got it, so we're talking about 50-60 hours.
I have paired it with Beyerdynamic T5p's single ended, Shure SE846's and JH Audio Angies balanced.
Here are my conclusions:
Sound
I find the sound of the AK380 to be absolutely amazing.
When people say something sounds neutral, that implies that they know what the recording should be like - I am not sure I do always know what was intended, but it seems very clear to my ears that the AK380 is trying as hard a possible to paint an accurate picture of a piece of music. In fact it is this 'rendering' analogy that I keep coming back to - its like upgrading a graphics card and the image you see in a game being that much clearer and refined.
As I have said before, the bass coming out of the AK380 is the finest I have ever heard. When paired with the SE846's I get a sound like a massive Krell amp in my ears - astounding - a lot of fun. When paired with the T5p's or Angies the sound is more balanced, but the bass is still so incredibly detailed.
For me, the mids are just right. Neither too forward nor back for my tastes. Smooth and sweet. Again which earphones you use changes the experience, but for me it has never been bad. Probably the Angies sounded best with the mids.
The highs go very high and this allows HD music to really sound startling. Cymbals and reverb and all the noises in the top register provide an amazing level of micro detail.
Micro-detail
I think that the AK380 renders everything that is stored in the file that you are playing and so all the detail in there is revealed. I have heard things I have not heard before in the music I have been listening to for years - yes, very surprising - the background sounds from the studio are discernable!
In between tracks the AK380 is as silent as I can imagine - even with the incredibly sensitive Angies there is no hiss.
Sound-stage
The sound-stage is as wide as you earphones will go.
UI
I personally believe that the A&K player UI is the best out there. The only one that came close for me was the NW-ZX2, but the full android experience on that meant way to much clutter and bloat for me. I think A&K have achieved just the right amount of functionality.
AK Connect
This has the potential to be huge - it can even be used to stream music from one A&K device to another (240<->380 is possible). I think this could be a game changer.
Build Quality
Faultless - nuff said. The device is beautiful.
The Magic Word: Synergy
This word has been used on this thread recently and I believe it is key when you talk about the AK380. I honestly believe that the AK380 can provide a balanced sound across the whole audio spectrum, and can provide an accurate musical representation to whatever earphones you use. It is not going to be the bottleneck in your system. Therefore it ends up being the job of the earphones to deliver that sound to your ears.
The earphones you choose dictates what you hear. The AK380 has always sounded good with my three earphones, but they are all expensive. There is no point in buying an AK380 if you are not going to spend some decent money on the earphones you connect it to.
This leads to the perhaps the only pseudo-issue with the AK380 - it does not artificially flatter sound at all (say, like the NW-ZX2). So, if you have a bad recording with hard treble, it will sound like a harsh recording with bad treble. If you ave crap earphones, then you will hear crap. It is not the AK380 sounding crap, it is the music and/or earphones sounding crap.
Conclusion
To my ears the Ak380 is a definite improvement over the AK240 - The AK240 also sounds amazing, but the AK380 sounds more mature and larger, and the bass - oh the bass!!! On a side note, It makes the NW-ZX2 sound like it renders music through mud.
The unit does get warm if you listen to it continuously, and once it is warmed up is sounds even better.
On top of that we have the amp coming out soon - What is that going to sound like.
My only problem now is that I now have to decide which earphones to keep. The JH Audio Angies sound beautiful when paired, with bass at about 3pm. The SE846's are like a party in the head - the subwoofer is really used by the AK380 as it outputs well rendered bass even down there (see my earlier comments about Yulunga by Dead can Dance). The T5p's are probably the most spacious sound, but they are not portable so I only listen to them in my office at home. Decisions, decisions, wish I could afford K10's and Layla's as well. The AK380 makes me want to go to the next level because I know thats where it belongs.
If you can afford it and understand the fact that it will lose value at some point (something that some people seem to not understand) then I highly recommend it. It is a solid foundation in your portable sound system. BTW it is still available in the UK Ebay store at a price that is lower than some shops are selling the AK240 for - look and confirm that there is no import duty before buying.
Happy listening, and hopefully see some of you in London next Sunday.