OMG! Just listened to this DAC, and it is AMAZING! I'm listening to it on Hifiman HE-400's (modified) and comparing the M8 to a Cambridge Audio Azur 840C reference player/DAC, MSB 24/96 Link III DAC, and Emotiva XDR-2 DAC, and the ifi nano DSD. (I also own other headphones, like the Sennheiser HD600s, but mainly use the modified Hifiman for critical listening.) I'm using the ifi iCAN as a headphone amp, but also the Little Dot III tube amp, Headroom amp, etc.)
First off, some context: I mainly listen to classical, choral, acoustic jazz, and some pop and R&B. (I'm an avid listener and concert-goer over the past 30 years, with about 15,000 CDs and several thousand LPs in my collection.) I'm not an audiophile, but I do appreciate well-recorded music. Also, I am not into gaming, and realize others may have different musical tastes And as with any audio review, much of it is the personal preference of the writer. With that said...
The main impression of this DAC is light and airy, with good sense of timing and space. Like the Azur 840C, it does well separating instruments and removing that 'in-your-face' feeling other DACs leave one with. The midrange is fantastically clear (critical to choral and opera) and the instruments in large orchestral compositions do not get muddled together. Great detail! I would put the sound quality at or near reference DACs costing 10 or 20 times more. A no-brainer bargain.
I'm just now listening to the Erato recording of Offenbach's "Tales of Hoffman", with Natalie Dessay singing the famous aria, "Les oiseaux dans la charmille," What a tour-de-force! This is one of "test" recordings and I must say this DAC brings out the clearest harmonics and dynamics I have *ever* heard on *any* reference system. Very impressive!
I realize opera is not everyone's cup of tea, so will offer another impression with Diana Krall's "Only trust your heart" CD. This is another difficult recording to render faithfully, as it has much sibiliance with Diana's voice and can come out sounding rather harsh on lower-end systems. Lewis Nash's delicate brush work on the drums can also sound like tape hiss or static, and its soundstage is often compromised. Not so on the M8. Again, I would put this playback at the top of that which I have heard on other reference systems.
One could go on, but you get the idea. This little DAC pushes all the right buttons for me, and costs less than many of the audio cables I have connecting the rest of my systems... And did I say this unit was TINY?! I didn't realize how small it was, as I saw few pictures of it with anything around it for scale. It's not much bigger than a deck of cards and looks like it was shrunk in the wash! Nevertheless, the sound it delivers is quite impressive.
At $149, this DAC is highly, highly recommended.
PS: my listening chain for this review: Cambridge Audio Azur 840C -> SMSL M8 -> ifi ICAN -> Hifiman HE-400 (modified). As the 840C is a $1,500 player, I swapped it out with a budget player (Onkyo C7030) that is less than $200, with no discernible difference in sound. The M8 is that good.