I want to start by thanking Andy of Cayin for giving me a chance to hear the N6ii with both it's A01 and T01 modules thru a brief in home demo. I've had a chance to hear quite a few of the Cayin Digital Audio Players over the years and they've always impressed me!
Some history for my self, I am a happy owner of a Hifiman HM901 that I run exclusively line out into a Custom iBasso PB2 amp. Sound quality of this system has for years been unchallenged by all of the modern Digital Audio Players I've heard. Still this old vintage player has terrible battery life, no streaming support and the amp it self is twice as thick as the already large player. So my little tower is by no means a shining example of "portable" sound quality. Price was around $1500 when all components were available.
That said, I'm really impressed with the N6ii with it's T01 module. I feel it may be the first modern all in one DAP to match the quality of my transportable tower with dynamic headphones! As of the writing of this article, N6ii with it's stock A01 module is $1119 and the T01 module is avalible for $339. Bringing the total cost of the system as I am reviewing it around $1450.
Regarding the A01 module, I found it's performance was rather average when compared again'st both vintage and more modern Digital Audio Players. I'll cover it's performance briefly but will focus most of this content around N6ii with the T01 Module.
User Interface & Build Quality
N6ii runs off a custom android core and comes with Google's play store pre-installed, it's swipe down menu has a few custom audio specific audio options listed in addition to the normal options for android devices.
It's lock screen also features some meta-data that's relevant to the music your listening to at the time as well as some play back options.
For this review I did stick to using the pre-installed Cayin Music App for offline files and had success in running the Qobuz and Tidal Apps.
Physically the N6ii is well built, the side buttons and volume wheel have good tactility. Their responsive and have a sturdy feel to them, additionally each of the input & output sockets are solid without a soft feeling or any wiggle from the jacks.
Both the stock A01 and T01 cards have 4.4mm balanced and 3.5mm single ended output and with each performance is best out of the fully balanced 4.4mm socket. Cayin also included a 4.4mm to 2,5mm adapter, a smart and thoroughly appreciated included accessory given the popularity of 2.5mm in balanced portables over the years.
Given how drastically the sound quality changes between the Modules I'd like to start with how A01 compares to something with a similar sound signature.
Both A&K Kann and the A01 module feature a robust AKM 449# DAC chip-set that embraces the "velvet sound" in AKM's Velvet series of DACs.
In theory you'd expect A01's 4497 chip-set to bring forth a more resolving presentation over Kann's older 4490 but I felt both were more or less on par with one another. Each has a similar "romantic" presentation. Soft round lows, sweet highs and a lush mid-range. Both A01 and Kann's envelope feature an exaggerated decay and sustain with de-emphasized attack.
There's weight to the sound, body and a rich fullness but everything's heavier, softer and slower than what feels natural. "Fun" or "V-Shaped" headphones will benefit from this kind of presentation, I however don't really own or enjoy headphones with that kind of sound. I will say A01 did prove to have more headroom than Kann and handle'd harder to drive headphones with more authority and clarity overall. HD 600 saw no difference but Aeon Closed 2 did perform worse with Kann than N6ii A01.
N6ii T01 - Dual PCM1792A
Frankly to my ears I've always enjoyed the presentation and implementation of the Texas Instruments or TI PCM Dac chips. When correctly implemented they are mostly linear with a tiny bit of "air" on the top end.
I'm happy to say I feel Cayin has perfectly nail'd the spirit and majesty of the TI PCM series of Digital Audio Converters. Linear bass reproduction, perfectly natural mid-range and a slight bit of air on the top end. Overall the envelope is to my ears perfectly balanced from the lows up through the central and upper mid-range. Technically this "air" or "airiness" is to some extent an exaggeration. However I don't find that the top end has any emphasis on the attack but rather some exaggeration on the sustain and decay.
With bright headphones this can be a bit distracting but I much prefer even this slight exaggeration over the sluggishness of the "Velvet" Sound.
My long standing tower stack is composed of the Hifiman HM901 which itself features a dual arrangement of ESS Sabre 9018 DAC chip-sets. In stock form and most implementations the Sabre DACs are mostly linear in the bottom end with an aggressive presentation in the mid range and top end.
What I love and have loved about HM 901 is it's "vintage" High Frequency roll over filter, I typically don't enjoy these filters but on HM 901 it removes that slightly aggressive presentation and adds helps improve mid-range tonality.
Each of the internal AMP-Cards for HM901 were disappointing, so over the years after hearing many different amps and topologies I settled on the iBasso PB2 amp with a quad of LME 49990 OP Amps with an Energizer Linear Battery Pack.
With my Sennheiser HD 600 I was hard pressed to find a real discerning difference between my existing stack and N6ii T01.
However with my Aeon Closed 2 there was better presentation of textures in sub bass frequencies with the HM901/iBasso PB2 stack. I also felt the HM901/PB2 Stack presented a more discernible and cohesive sense of space especially for tracks where large drums or heavy bass lines are present. Which I feel is related directly the amplifiers improved control over A2C.
Tonally tho I did feel at times N6ii T01 was maybe at times just a tiny bit more energetic, maybe airier but for as many tracks as N6ii T01 was better there are tracks where it was worse.
N6ii T01 Headphone Impressions
I quite simply loved N6ii T01 with my HD 600 which I run it with a balanced ZMF Atoms Copper cable.
Overall I was impressed with both it's detail and overall staging and cohesion. Tonally quality was excellent to,
- Snappy with an even envelope
- Without sounding over-emphasized or too fast
- Easily discernible sense of weight and body, reverb in larger instruments was apparent
- Natural tonality
- Smooth but not lacking texture
- In that you could discern the literal nature of vocals - the movement of air
- Natural tonality
- But not smoothed over
In contrast the A01 and "Velvet" AKM sound does help to tame HD 600's slight shout, but for my tastes I again felt HD 600 was slow and veiled with the A01 chip.
I'll also add that T01 does not help with HD 600's rolled off sub bass, tho it doesn't draw attention to nor away from it either.
Again I felt this combination as a whole was mostly transparent.
Dan Clark Audio's new Aeon 2 Closed is one of my favorite closed backs right now, while it's low impedance makes it some what easy to drive it's low efficiency does hinder bass extension when amplification is not sufficient.
In the case of N6ii T01, unfortunately I did find it's amplification to be insufficient for driving A2C at it's full potential. There was a discernible lack of authority and definition in the sub bass especially.
Which for some tracks where I find A2C to be too bass heavy the lack of authority and power is sorta of pleasant tho the lack of detail is not a worthwhile trade off.
However, I will say using the line out of N6ii T01 into my iBasso PB2 was excellent.
Cayin N6ii T01 is for me the first Digital Audio Player to fully eclipse my old HM901 stack, its user interface is quick and both it's amplification and analog line out stages are excellent. For any one looking for a transparent portable digital audio player I highly recommend the N6ii with T01 module!