Comparison.

In this test, I was using Jewel and Amber Pearl to listen/compare between N3U and other DAPs, volume matched.  Each of these DAPs, besides a difference in tonality and pair-up synergy, has its Pros/Cons, all of which should be taken into consideration depending on your preference and required features.  N3U was set to Classic Tube mode and Med gain, except for the comparison with N3Pro where I tested different Timbre modes.

N3U ($529, 2x AK4493SEQ) vs N3Pro ($479, 2x AK4493EQ) – I started this comparison in Solid State mode from BAL output between DAPs.  The soundstage expansion and imaging are relatively the same, both being not as wide as in Tube mode, but similar between the DAPs.  I do hear some difference in tonality with Ultra being smoother, a bit warmer, and having softer bass, while Pro is more energetic and with a stronger bass impact.  When I selected Tube mode (Modern in N3U) I had to switch to 3.5mm output since N3Pro can only be used in Tube mode from SE.  With Modern (N3U) vs UL (ultra-linear in N3Pro), I still hear Pro being a bit more energetic and cleaner while N3U has a smoother more textured tonality.  Switching to Classic Tube (N3U) brings the tonality to a similar sound tuning as Triode (N3Pro) mode, being smoother, with a laidback fuller body, and slower attack, but Classic Tube (N3U) has a better technical performance than Triode (N3Pro).  Classic/Ultra has a wider soundstage, improved layering and separation of the sounds, and more expanded vertical dynamics which makes TR/Pro sound a bit compressed and less detailed in comparison.  One thing to note, since I wasn’t able to use Tube mode from the 4.4mm output in Pro, the 4.4mm output in N3U has improved soundstage expansion and more holographic imaging.

N3U vs Lotoo P6k ($1k, AK4493) – both daps have a smoother tonality, but there are quite a few technical differences in this comparison.  First of all, N3U has a noticeably more holographic presentation of the sound, both in the way how soundstage expands and how imaging positions the sounds in space.  With N3U you feel like you are in the middle surrounded by the sounds while with P6k you feel like being in front of the sound.  Notes in N3U have more heft, more weight with a fuller body.  Both have a good bass performance with IEMs I tested, but I noticed more sub-bass texture with N3U while faster mid-bass punch with P6k.  Also, with mids/vocals, both have smoother tonality, but N3U has more texture and more laidback musicality, while P6k has a faster sound pace.  Also, I can hear a bit more air with N3U vs P6k in treble.  When switching N3U to SS output, I preferred P6k, but in Classic Tube mode, N3U was my choice.

N3U vs Hiby R6iii ($500, 2x ES9038Q2M) – R6iii has a nicely expanded spherically shaped soundstage, but N3U still stretches it a bit wider, especially noticeable with some percussion sounds which I’m hearing around and in the back of me while more to the side with R6iii.  Also, N3U has more holographic imaging with the positioning of sounds creating more depth in overall presentation.  When it comes to tonality, I had to switch R6iii from Class AB to A because in Class AB the sound was brighter, “lighter”, and even had some digital glare (treble harshness) since I was focused on the texture of the sound after spending a lot of time with N3U.  Switching to Class A in R6iii does make a difference, especially in taking the edge of the treble, but it is still no match for N3U even in Solid State mode.  Tonality here is quite different with a smoother and more textured sound of N3U vs cleaner and lighter sound in R6iii.

N3U vs A&K SE180 ($1.5k, w/SEM2, 2x AK4497EQ) – a difference in soundstage expansion and imaging was the first thing I noticed.  With the IEMs I tested, SE180 had more depth than width, while N3U had a more spherically expanded staging with more holographic imaging, and that was quite noticeable.  When it comes to the tonality, the SE180 w/SEM2 card had a very similar sound to N3U in Modern tube mode.  It was smoother than N3U SS mode, but not quite textured or having as fuller body as in N3U Classic tube mode.  I did notice N3U to have more bass punch while the same IEMs with SE180 had a bit softer bass.  With N3U in Modern tube mode, they both had a similar tonality mids/vocals and even similar sparkle in treble.  The presentation of the bass and soundstage expansion were the biggest differences here.

N3U vs iBasso DX170 ($450, 2x CS43131) – in this comparison the soundstage expansion and the imaging are nearly identical. Both have a spherically expanded soundstage in all 3 directions and holographic imaging.  Both also have a natural tonality of mids and airy sparkle in treble.  But I do hear a few noticeable differences.  With the IEMs I tested, N3U has a tighter and punchier bass while DX170 bass is more rounded and more laidback.  N3U mids have fuller body tonality with more texture, like a light tubey distortion while in comparison DX170 sounds cleaner and a bit “edgier”.  I also noticed a similar thing with their treble, both have an airy sparkly extended treble, but N3U has fewer “grains” which takes the edge off its intensity.

N3U vs iBasso DX260 ($949, 8x CS43198) – in this comparison, the soundstage expansion and the imaging are nearly identical as well (just like in DX170), with both having a spherically expanded soundstage in all 3 directions and 3D level of holographic imaging.  Tonality here is getting closer as well.  DX260 is a warmer-tuned DAP, so they both have a similar natural organic tonality.  With IEMs I tested I hear a similar weight and punch in bass, fuller body smoother mids/vocals, and airy extended treble.  Unlike DX170, the DX260 treble has a similar natural sparkle as the N3U.  After going back and forth many times, the main difference I found in this comparison was relative to the mids.  DX260 presents its mids more forward while N3U has its upper mids slightly more laidback.  Also, while I can sense a texture in the tonality of mids in both DAPs, N3U comes off as being more analog and tube-like, while DX260 texture sounds “cleaner”.  The texture of the N3U Classic Tube mode has its unique characteristics.

Wired connections.

In this section of the review, I will go over various wired connections I tested and verified with N3U.  Typically, in most of my DAP reviews this section covers both wired and wireless connection, while here only wired will be available.  If you want to stream on the go, then use N3U as a wired usb-dac with your smartphone.

Digital usb-c out

You can use N3U as a digital transport which I verified by connecting RU7.  Once connected, the N3U volume was set to 0 automatically, and I was only able to adjust the volume from RU7 (the same verified with other dongles as well).  The sampling rate of songs from N3U was correctly displayed on RU7, and the overall sound was similar to when I connected this dongle to other DAPs and my smartphone.

Coax out

You can also use N3U as a digital transport by connecting a device like iFi micro iDSD BL using Cayin CS-30TCR Type-C to coax cable.  In that connection, volume was only adjustable from iDSD, even though I was able to use the N3U volume wheel which didn’t affect the iDSD output.  I also tried micro iDSD with N3U using usb-OTG cable but preferred coax which yielded a bigger and more holographic soundstage expansion and more expanded vertical dynamics.

Line Out

LO connection is self-explanatory.  Both 3.5mm and 4.4mm of N3U can be used as PO or LO, and with BAL output you just have to select it from the menu which I did while connecting the C9 amp to N3U.  Once connected, the N3U output is fixed and can’t be variably adjusted.  You can only adjust the Line Out output setting with Low/Mid/High based on a corresponding fixed output voltage I mentioned previously in the review.  One interesting observation was a comparison between N3U in Classic Tube mode vs N3U + C9 in dual NuTube where JAN6418 tubes of N3U gave the sound a fuller body and more “tubey” tonality in comparison to NuTube of C9.

USB DAC

I saved the best for last.  When connecting N3U to my Win10 ThinkPad T480s, I had to select the USB option from the notification bar for Audio in.  There are 2 available choices with and without USB power.  While using the laptop, I selected USB power since I don’t care about draining its battery.  Plus, by selecting it, I was able to use N3U as a USB DAC while also charging it from my laptop.  N3U was recognized by the laptop and I was able to use it as a USB DAC right away, being able to adjust the volume from both the laptop and N3U.

The same worked flawlessly while connecting N3U to my Galaxy S22 smartphone using a usb-OTG cable, but here I chose a connection without USB power so I don’t drain my phone’s battery.  I confirmed that N3U wasn’t being charged while connected to my smartphone, only using its internal battery.  I was able to adjust the volume from both my phone and N3U.  There was not too much difference in the sound quality between these sources.  Also, while streaming from Amazon Music HD, I noted that the sampling rate was displayed correctly at 192kHz.

One important thing to note, when you are in the USB DAC mode screen, you can’t swipe down the notification bar or go to the main Home screen.  But you can click in the upper right corner on “gear” Audio Settings to have access to change the Gain and switch Timbre setting (SS vs Tube) and Tube Timbre (Modern vs Classic).

Conclusion.

As I mentioned in my N3Pro review, which is also applicable to N3U, relative to other DAPs in Cayin’s current lineup, N3Ultra is considered to be entry-level, but there is absolutely nothing entry about it except its price.  Each of Cayin’s DAPs is packed with so many unique features, that sometimes I’m having a hard time putting a tier label on them.  But one thing is for sure, the Ultra version of N3 felt superior to its Pro version.  Still featuring a pair of Raytheon JAN6418 tubes like in N3Pro, Cayin N3Ultra was completely re-designed.  You can now use 4.4mm BAL output with tubes and still select 2 distinct Tube sound-tuning modes.  You have access to a bigger display and a faster GUI, running on Android in the background.  Plus, you get a Parametric EQ.  There is no tube ringing and the overall sound performance was refined as well.

One thing you will not find here is any type of wireless connection because Cayin wanted to eliminate any wireless signal interference with Raytheon miniature vacuum tubes and offer a pure audio experience without any hiccups.  This means you can use N3Ultra with a microSD card for local playback or as a USB DAC connected to your laptop or smartphone.  You can even think of it as a vacuum tube USB-DAC dongle with a built-in battery, to use with your smartphone for streaming.  But regardless of how you use it, you have a choice of 3 separate timbre selections.  Solid State has a clean and clear, neutral detailed sound, Modern Tube adds more weight and texture, and Classic Tube scales it up to the next level with more analog texture, improved retrieval of details, bigger holographic soundstage, and expanded dynamics.

Overall, N3Ultra packs a list of impressive features.  But in my opinion, the Tube’s output, especially Classic mode, is still the main attraction of this DAP which makes it stand out from the crowd because you will not find another audio player with tubes to compete with N3Ultra in this price bracket.