Oooh, where should I start, my now almost six hours with the device? I am by no means qualified to do a review, these are merely my first impressions, and I've never really written stuff like this before, so pardon the crudeness of my writing.
I'll start off with the easy - build quality and my issues with the unit. Everything about this product screams quality the moment you pick it up, the impression akin to the durability of god - truly, everything...apart from the buttons. Those are abysmal. I mean, in contrast to everything else they are borderline criminal, not only in the fact that they spin and rattle, but also the fact that, for example, I have found them to be unreliable around once or twice in say 80-100 presses. Also, switching from XBass+3D to bypass involves a split second of peaking audio/ear rape, depending on volume (the louder you play the worse it peaks, but I learned quickly
). Something I would expect to be addressed in a next revision. With nothing playing changing the volume crackles, which I think is fine, since during playback you'd only hear it (and faintly at that) if you were running your source at -30dB output or something. Somebody already mentioned the right channel getting power before the left on the lowest audible volumes. Again, not an issue in normal playback. The knob is a dream to turn tho, kudos for that!
Alright, that covers that.
Now, onto what actually matters. Disclaimer: I am using a Digitech RP155 audio interface as my DAC, to my ears it is clearly better at crunching audio math and spitting out analog than my laptop (MSI GE63VR), my headphones are Audio Technica ATH-AD500Xs with swapped pads (Brainwavz pleather) and my sources are Tidal HiFi mostly and Spotify Premium from the laptop.
First impressions: infinite power. Previously I used a HTIB receiver for my headphones, and it had a very noisy output already at moderate volumes. Now, I have a very unhealthy listening habit, challenging the very biology of my ears, it is truly a wonder how I can still hear above 19.5kHz, I do try to rest my ears after each song tho, nothing the old 10 hour rain remix on YouTube can't help. That is to say I like to listen to music loud.
And oh boy, are the differences more clear than anything at above moderate volumes. The impression follows as such: in music, what I had suspicions of, I can now easily confirm - the sound is effortless, unforced, and thus not painful whatsoever. I usually have a lot of hearing fatigue after listening for so long, but I still haven't noticed any with this amp. Because of the headroom (which is what gives the impression of effortless power delivery), the mids and highs don't feel suffocated, before it felt like the details would just be muddled by the bass whenever the latter hit in, now the detail in the music scales perfectly with sound pressure and is undisturbed by action in the nether regions, which quite honestly is amazing.
Another thing I noticed that it sounds better at low volumes as well. Music doesn't seem to lose excitement as fast when lowering volume as compared to what I was used to.
Yes, the clearest difference to me is consistent separation and considerably less listening fatigue. A very lazy conclusion, I know, but I still haven't tried gaming with this amp. The only problem now are my headphones, they are the limiting factor now.
TL;DR: coming from a s**t amp this makes me feel I've never heard my headphones before