Sound Analysis – Overall.
The sound analysis of N8ii was done using Oriolus Traillii, playing a selection of test tracks, such as Agnes Obel “The curse”, Sandro Cavazza “So much better” (Avicii remix), C-Bool “Never go away”, Ed Sheeran “Shape of you”, Alan Walker “Darkside”, Galantis “Hunter”, Iggy Azalea “Black widow”, Indila “Boite en argent”, Dua Lipa “Love again”, Counting Crows “Big yellow taxi”, David Elias “Vision of her”, and Michael Jackson “Dirty Diana”. I had about 150hrs of burn in time before I started analyzing N8ii.
I prefer to describe the DAP sound based on the comparison to other DAPs and pair ups with different IEMs/headphones since the DAP by itself doesn’t have a “sound”. What we hear is how the sound characteristic of a source shapes the sound signature of connected IEMs/headphones or the difference in sound relative to other sources using the same pair of IEMs/headphones. As a result, this section of the review usually summarizes what I find in the follow up Comparison and Pair-up sections. Of course, this is my subjective opinion, describing how I hear it.
I found the tuning of N8ii to be more transparent and to have a natural revealing tonality. The difference in timbre setting between Solid State and NuTubes will have the effect on mids and vocals from more revealing and dryer (SS) to smoother and more natural (Tubes). But overall, it has neutral sound with a balanced signature leaning toward natural revealing tonality with expanded vertical dynamics (both micro and macro), black background (very quiet noise floor), and relatively fast and clean transient response of notes with details popping out of the blackness, even when it comes to sensitive iems.
The Tube mode gives instruments and vocals more body, more texture, richer timbre, while still keeping the sound quite resolving, layered, and with impressive retrieval of details. Those who are familiar with the original N8 or C9 amp, know that NuTube is not your traditional “tube” that colors the sound. NuTube’s double triode tubes are rich in texture, not coloring or saturation. But still, when you switch from Tube to Solid State, you can sense more transparency and less coloring in sound.
Soundstage is big, especially from balanced output, expanding in all 3 directions, making the sound very spacious and open. Also, impressive 3D holographic imaging with a very precise and accurate placement of instruments and vocals in most of my IEMs and headphones.
4.4mm vs 3.5mm.
The only noticeable difference I hear is in soundstage width, spreading wider (Left/Right) when connected to balanced output. Also, BAL has more power, thus SE needs a few more volume clicks to match it. Otherwise, tonality, sound sig, and overall technical performance were nearly the same.
N8ii is relatively quiet with Solaris 2020, passing my Agness Obel “The Curse” first 30sec test without a problem. I tried it with P/P+, SS and Tubes, and Class A/AB (in P mode). There was just a slight background waterfall hissing in high gain, but nothing in middle or low gain.
Tried a few extended listening sessions streaming Amazon Music HD and Tidal, and even with my S22 phone next to N8ii I haven’t noticed any EMI interference.
Sound Analysis – SS/Tube, Class A/AB, P-mode.
Please keep in mind that in P-mode (regular output), you have a choice of either SS or Tubes output and can switch between Class A or Class AB amplifier type. In P+ mode (higher voltage output), you also have a choice between SS or Tubes, but can only select Class AB amplifier. So, between P and P+, Solid Sate and Tubes, Class A and Class AB, not to mention 3 levels of gain on top of that, you have a lot of different combinations to try with your IEMs and headphones. To give you a better idea what you can expect, I partitioned my testing as following. Also, please keep in mind, while I find changes noticeable, nothing is night-and-day drastic.
The P mode Class A to AB comparison applies to both SS and Tubes timbre settings. Switching between Class A and AB is like going from a smoother and slightly more laidback and relaxed analog sound to a faster, snappier, and with a blacker background Analog/Digital hybrid sound. The difference in tonality is noticeable due to speed/attack change in the sound where in Class A – bass has a slower attack with less punch, mids are smoother, more relaxed, with a little more analog warmth, treble has a bit less sparkle, and in Class AB – bass has a faster attack with more punch and improved articulation, mids are more resolving, and have blacker background, treble has more sparkle and airiness.
In P mode Class AB, when switching from SS to Tubes, there is a clear distinction of the sound gaining more body and smoother analog texture in mids/vocals. As a result, in SS timbre setting the sound is dryer, has more precision and control, and faster transient of notes popping out of the black background. Switching to Tubes makes mids/vocals wetter, smoother, even a touch warmer while still keeping the same high resolution and retrieval of details. The technical performance doesn’t change as much, but the coloring of the mids becomes more apparent.
In P+ mode Class AB when switching from SS to Tubes, I hear the same changes as I noted above in my comparison while testing in P mode.
After a number of extended listening sessions, I found that in P mode with SS timbre I preferred Class A setting which gave me a perfect combination of faster sound with higher resolution and smoother analog coloring. But, when I was in P mode with Tube timbre, I enjoyed more Class AB amplifier setting to give the sound more punch, to improve the layering, and to add more sparkle to the upper frequencies.
In P+ mode, since Class AB was the only amplifier option, choosing SS or Tubes will depend on pair up synergy with IEMs I was using. For me personally, warmer smoother IEMs paired up better with SS while brighter or neutral tuned IEMs had a better synergy with Tubes.
Also, switching between P and P+ to boost the output voltage/power, had a different effect depending on your IEMs or headphones. For example, when listening to BA/EST iems (like Traillii), it didn’t make as much difference to my ears. But when I switched to hybrids with DD/BA/EST drivers (like Jewel), the bass punch had more authority, better articulation, and a tighter sound. This effect was even more noticeable when I used demanding headphones like my 470ohm open back ATH-R70x. The boost in performance of R70x when I switched to P+ was quite impressive, including a better articulation of bass notes, more clarity and blacker background in mids, and some expansion in soundstage. Also, I noticed same changes with Meze Audio Empyrean.
Overall, P+ with Tubes and Class AB was my favorite setting with most of my IEMs and headphones, but I also enjoyed Solid State with P+/AB. I think the choice will be based not just on pair up synergy, but also the preference of tonality. Either one offers a unique finetuning of the sound and makes you feel like a mad audio-scientist, experimenting with different settings.