You bought it recently in Singapore? Glad that the firmware upgrade is working out for you.
Kozato: yes I did - bought in Singapore last week. FW upgrade to 1.40 definitely made a difference in SQ.
Early impressions are that earphone pairing makes a huge difference:
Shure SE535 with stock cable or with Moon Audio Silver Dragon cable: not good at all. Just harsh and trebly.
Earsonics S-EM6 with stock cable: fantastic all round sound. Smooth overall; more forward-but-rich mids without losing bass or treble. Great for all kinds of music. Closer to Shure SE846 sound with stock cable. Punchy, decently compressed nightclub sound with dance music, and really enjoyable punchy wake-up vibe with rock music.
FitEar Melomane limited edition with stock cable: not as punchy as the Earsonics but better separation and wider soundstage. More "hi-fi".
The elephant in the room: comparison to iPhone 6 with Tidal tracks (16/44 or better): iPhone has a lovely, wake-up-and-smell-the-coffee punch but MSAK120 is smoother, richer and much wider soundstage.
Extra points: MSAK120 into Chord Hugo (Toslink) with Earsonics, FitEars or Denon D7000 closed back headphones: amazing smooth, detailed sound.
Elephant in the room 2: iPhone 6 into Hugo via Toslink and listening to hi-res tracks through Onkyo HFPlayer and all IEMs: sounds amazing. But less x and y axis (width and depth) vesus MSAK120 + Hugo.
Summary: as things stand, best totally portable solution for me, with all types of music, is MSAK120 with Earsonics S-EM6 IEMs. Except for EDM, in which case the FitEars probably sound better. I would be very happy on desert island with just MSAK120 and either IEM. The Earsonics sound smoother and perhaps musically lovely; the FitEars are more hi-if and wider soundstage.
MSAK120 with Hugo is awesome, with Earsonics or FitEars. Having auditioned the DAP with balanced connection, I'm genuinely excited about posting impressions with balanced cables as mentioned above.
Caveat 1: waiting for balanced cables from Ted Allen at Headphone Lounge for the Earsonics and Shures (I will probably get the SE846 next week).
Caveat 2: waiting for UM Merlin universals to arrive. Earsonics balanced cable should fit the Merlins. Impressions to follow after that.
This exercise has confirmed what we all know: once you get a high-end DAP and properly high-end IEMs, it's more about preferences than better or worse sound quality. I've just spent an hour A/B-ing my Earsonics and FitEars (all in single ended mode) and they both sound amazing through the MSAK120.
In short, I absolutely love the DAP with this mod. And while I'm a huge fan of just sticking a high-end pair of IEMs into an iPhone 6, the AK120 kills the iPhone for soundstage, separation and overall rich sound. It really sounds fantastic.
I told the Mezzo guys that I would consider the Glove Audio A1. They replied pretty quickly that it's not worth it, because the sound out of the MSAK120 is cleaner. Without having tried it, I'm happy that the DAP sound solo, with single ended connection, is amazing. I won't pre-suppose the balanced sound, but considering that what I'm already hearing is the best DAP sound I've ever heard (and yes I've tried the AK120ii and AK240), it's all good from here.