After 300 hours of burn-in:
The burn-in process is not over yet since the sound is still changing (mostly improving). According to Kingwa, it can take up to 400 hours for the sound to settle.
Below are my impressions after 300 hours of burn-in.
The low level resolution
The low level details are outstanding with this DAC. I am not referring with low level resolution to the definition of the sound in quiet passages (which is also excellent), but I am referring to very subtle sounds when there is already a lot going on. Small sounds are not masked by louder sounds playing at the same time : this is especially true for classical and jazz recordings but also all well recorded live music (such as Hell Freezes Over by the Eagles).
This Dac doesn't try to fake high definition by just sounding brighter and drier (such as the emu 0404 usb). The higher definition here serves a more natural portrayal of music as the listener doesn't have to make as much efforts to listen to the small details.
These impressions were done using the Hifi Cables & cie Khnoum interconnect and ST-3 head-amp. When I changed the head-amp and interconnects those qualities were somewhat diluted.
Cable swapping : Sharkwire vs. Hifi Cables & Cie Khnoum Interconnect
After giving the Sharkwire interconnect close to 100 hours of burn-in, I gave it another critical listening. The sound definitely improved with burn-in as it doesn't sound dull anymore.
Compared to the Dh-Labs Sonics BL-1, I would say it has say that in my system it has around the sound bandwidth extension but they have two different characters : the dh-labs sound a little bit forward and bright while the Sharkwire sounds a little bit warm and overall it is more pleasing to the ears. The definition level is roughly the same. The kimber PBJ compared to both cables has less high frequency extension than both cables and is otherwise pretty similar in mids an bass.
However, the big surprise was when I switch back to my reference interconnect : the Hifi Cables & cie Khnoum interconnect. These interconnects are simply wonderful, they simply disappear. While comparing the other interconnects I have (dh-labs, kimber PBJ, Sharkwire), I could always pick-up defficiencies with them : frequency extension at the extremes, tonal balance, definition, soundstage, ...
With the Hifi Cables & cie Khnoum interconnect, the first thing you notice is that soundstage seems to extend very and the low level resolution is truly outstanding. The bass extends very low and the highs are crystal clear. Those interconnects let you experiment a thereness/presence experience. It is truly unbelievable how much a pair of 50 cm of wires can let you change the sound of a system.
These are the differences I heard using the audio-gd ST-3, it was less apparent when using the little dot mkIII.
Head-amps : Audio-gd ST-3 vs Little dot MkIII
My little dot MkIII was rarely used as a headphone amp since the time I fully burned in the ST-3. When using the DAC-100 as a source, I clearly preferred the ST-3 (as they were made to be used as a pair anyway). In fact, I found another usage for the mkIII as a tube buffer between my dac and my desktop speakers (the gigaworks s750). It sweetened the somewhat dry sound of those speakers.
However, since I was trying to get a better sense of how the DAC-19mk3 sounded, I thought I should try it in another head-amp than the ST-3 to get a comparison. So I put the mkIII in place of the ST-3 using the same power cord, the same interconnect and the same isolation components I have been using with the ST-3 (vibrapod cones, plywood and carbon fiber rigid sheets). This experiment made me realize just how vibration control is important on tube gear.
Dynamics : the Little dot mkIII was to my surprise the clear winner in macro-dynamics. However, when I listened more carefully I realized that much
Soundstage : the little dot mkIII has a wider soundstage but a less defined one. While the soundstage with the st-3 is smaller, it is razor sharp defined and there is a better separation of intricate sounds
Transparency : Here the ST-3 is the clear winner by a very wide margin. If I were to make a comparison with tv resolution, I would compare the little dot to standard def 480p and the ST-3 at high def at 1080p.
Timbre : While one might expect a tube amp to offer a better refinement in sounds, it was the opposite in my system. The ST-3 let me hear (thanks to its superior resolution) more refinement and differences between sounds especially when listening to non amplified instruments (violins, pianos, ...).
Tonal balance : when comparing both amps, I realized that the little dot mkIII was the better balanced amp. The ST-3 can reach very low in the bass while its highs don't extend as much by comparison in the treble. Therefore, it sounds slightly bass heavy with the sennheiser hd-650.
Overall, I found that the 2 amps have more sonic differences thant the last time I reviewed them with the DAC-100 (Compass DAC), this is because the more neutral DAC-19mkIII and the more neutral cables I am using allow me to hear more easily any differences. I guess it is time I upgrade to a more appropriate amp.
Conclusion (after 300 hours of burn-in) :
To sum up, I cannot find any discernible sonic character/fault with the DAC-19MKIII using my current equipment but here are the main impressions : Excellent definition and low level resolution, High dynamics, Very deep and articulated bass, Sweet and natural highs and most of all, it is "analog" sounding.
I will update my findings once I upgrade my headphone amp.