Cayin N3Ultra: an Entry-level Portable DAP that Delivers a Complete Vacuum Tube Audio Experience
Mar 1, 2024 at 8:39 PM Thread Starter Post #1 of 877
Nov 16, 2013

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The MSRP of N3Ultra is US$529

N3Ultra: an Entry-level Portable DAP that Delivers a Complete Vacuum Tube Audio Experience

In 2024, Cayin enters its 10th year in the portable product line.

August 17, 2020, marks the launch date of the N3Pro DAP. As the first portable audio player equipped with the NOS vacuum tube JAN6418 (Joint Army-Navy designated military grade components) produced by Raytheon, it was the first in the sub-$500 price range to achieve dual vacuum tube timbres (triode and ultra-linear) and solid-state timbres in a DAP. Coupled with its relative portability, long battery life, low heat generation, and suitable pricing, it became one of Cayin's best-selling audio players.

Now, three and a half years later, the N3Pro's upgraded replacement model, the N3Ultra, is about to hit the market. We have debuted the pre-production samples at Canjam New York 2024 and released some preliminary information and photos on the HeadFI forum.

We shall present the N3Ultra today covering its features, functions, and design aspects of the DAP.

Photo Below: N3Pro on the left, N3Ultra on the right:

A major advancement in the batter against microphonic

The N3Ultra continues to use a pair of NOS vintage tube JAN6418 from Raytheon for the vacuum tube timbre. Although Cayin has not used this tube in other products over the years, the optimization of the circuit and structure for better utilization of this tube in portable products has never ceased. The JAN6418 is also one of the very few vacuum tubes that can be used in battery-powered portable products, given the various limitations of portable products on heat generation, power consumption, and power supply. However, its disadvantages are also very clear, namely its susceptibility to microphonic effects and poor resistance to interference from wireless signals.

On the N3Ultra, the JAN6418 is encased in a custom-molded silicon housing and installed on the left side of the DAP. It integrates into the chassis with a suspension structure, achieving comprehensive stress relief for the tube's filament. Meanwhile, Cayin's engineers have further upgraded the circuit architecture originally used for the N3Pro. By introducing an appropriate amount of inter-stage loop NFB to further inhibit the closed-loop gain, and employing FET to control the power supply of the vacuum tube, we can deliver a significant improvement in the stability of the operating current of the tube filament.

With the refinement and upgrade in structural installation and circuit architecture, the N3Ultra has effectively overcome the microphonic effect of the JAN6418. When users select one of the two vacuum tube timbre in the N3Ultra, whether walking with it in hand, carrying it in a backpack, or even during jogging which might involve vigorous shaking, the microphonic effect will not impact the music experience.

These features are open for audiophiles to verify in practical listening and usage. However, due to the physical structure of the JAN6418, unconventional scenarios like tapping the left side of the device with a finger or physically knocking it against a table surface can still produce a relative microphonic effect.

Gen3 Vacuum Tube Circuit: Taking JAN6418 Implementation into Another Step

Like the N3Pro, the N3Ultra offers two types of tube timbres: Classic (like the N3Pro’s triode circuit connection) and Modern (like the N3Pro’s ultra-linear circuit connection), providing an easier-to-understand nomenclature that highlights the tonal differences between the two circuits. The Classic timbre is thick, and warm, with rich overtones, best suited for vocal performances but weaker in dynamics and transients. The Modern timbre has a more open soundstage, with stronger extension at both ends and linearity. Thus, the naming follows the same definition as the N30LE, indicating consistency in sound presentation.

In its overall circuit architecture, the N3Ultra achieves a comprehensive application of tube timbre, allowing for the adjustment of the two tube timbres on both 3.5mm/4.4mm headphone output and 3.5mm/4.4mm line level output, marking a significant functional upgrade from the N3Pro.

Additionally, whereas the tube output power on the N3Pro was nearly half that of the solid-state output, the N3Ultra maintains equal output power for both tube and transistor timbres. This is the result of years of Cayin engineers’ research into the application of this tube circuit. We have changed the application of the JAN6418 in the N3Ultra circuit by using it as a low gain voltage amplification device (previously used as a BUFFER in the N3Pro without gain amplification), and incorporating a hardware analog volume controller to suppress the inherent noise of the tube.

However, it is important to note that the JAN6418 is a single-channel tube, with one tube handling only one audio channel. In the N3Ultra, when using the tube timbre for balanced output, the signal from the timbre circuit is inverted and serves as an inverted phase before feeding into subsequent amplification stages. Strictly speaking, the 4.4mm balanced headphone and line output are balanced driven, but this is not a fully balanced circuit from DAC to LPF to amplification. Conversely, the transistor timbre maintains a fully balanced process throughout.

A Complete Portable Vacuum Tube DAP Experience

Some users might wonder, "why only two vacuum tubes are used in the N3Ultra and not four?"

The JAN6418 tubes, produced mainly in the late 1970s and early 1980s, have relatively poor consistency compared to modern products. Using vacuum tubes in audio products requires testing and pairing before they can be used in the same device. The process of pairing two or four tubes results in a very low yield rate. Moreover, considering the need for the N3Ultra to be compact, lightweight, portable, and easy to operate, and to incorporate anti-vibration structures for mitigating the microphonic effect, it is physically impossible to accommodate four tubes within the N3Ultra. Therefore, the only practical solution is to use signal inversion for balanced transmission and amplification. We rather tell you the truth and assure you that we have done all we can to deliver a solution that is properly engineered, and practical for its designated purpose.

Additionally, due to the production processes of the time, the JAN6418, or traditional vacuum tube products (as opposed to the KORG Nutube 6P1), have very weak resistance to interference from wireless signals. When the tubes are close to antennas or wireless devices, users may hear a noise like a "sizzling" sound through the headphones, which severely affects the audio experience, turning the carefully designed tube sound into a potential flaw. These issues were experienced in our previous models, the N8 and N3Pro, which featured OTA wireless updating and bidirectional Bluetooth/Wi-Fi music transfer, necessitating internal antennas. Many users reported noise when listening to music when they selected vacuum tube timbre, and the problem was typically resolved by instructing them to turn off the wireless function after receiving a photo of the device's screen during playback.

Therefore, we have decided to get rid of the antenna with N3Ultra, this implies Bluetooth, or WIFI or features like online streaming will not be supported. Cayin is determined to let N3Ultra users to fully experience the exquisite and captivating sound of the vintage JAN6418 tube. All the decisions and compromises are made with this goal in mind. We are fully aware that the limited functionality may deter some users from choosing the N3Ultra and limit the circulation of this DAP. The focus has been primarily on the application and design related to the vacuum tube audio, which is a significant aspect of the N3Ultra, . This is our deliberate choice and commitment to develop a dedicated HiFi product for our users.

The Hardware configuration and performance

The N3Ultra's DAC employs two AM4493S chips in MONO mode for fully differential output, with a hardware analog volume controller NJW1195A from JRC. The DAP delivers a maximum output power of 600mW (at 4.4mm balanced phone output with 32Ω impedance), THD+N of 0.008%, and an SNR of 120dB.

Regarding the control system, the N3Ultra utilizes Android as its underlying operating system, with extensive optimizations to maintain the advantages of Android in touch display and charging management. The main processor is the Qualcomm 425, and the N3Ultra features a 4.1-inch HD 720x1280 TFT-LCD screen, breaking the limitations of the X1000E platform (whose maximum resolution does not exceed 800x480), and offering smooth touch operation.

The N3Ultra also features a new, closed pure audio system design for its UI, offering a clean and straightforward user interface. This closed system dedicates the hardware solely to music playback. It lacks internal storage but supports external TF cards and bidirectional USB DAC functionality, as well as coaxial SPDIF output embedded in the USB-C connector.

In terms of battery life, the N3Ultra is equipped with a 4500mAh battery supporting QC3.0 fast charging. Its battery life spans up to 12 hours or more in 3.5PO transistor mode and 8 hours or more in 4.4PO tube Classic mode. Weighing just 200g and with dimensions of 125x65.5x19.5 mm, the N3Ultra is compact and easily handled with one hand, making it more suitable for on-the-go use compared to the likes of the N30LE and N8ii. Additionally, it boasts excellent temperature control due to its simplified circuitry, which keeps the device relatively warm even in confined spaces.

Price and Availability

The N3Ultra will retail at US$529 and it will be available by mid-April 2024. We shall demonstrate the N3Ultra at two major events before we ship the DAP to our dealers: the Shanghai Headphone Expo by the coming weekend and the CanJam Singapore on April 6-7 2024. We shall try our best to showcase the new DAP to our users and press members before they make any decision,

Both the N3Pro, released three and a half years ago, and the upcoming N3Ultra, are unique in offering dual tube timbres plus a transistor timbre, totaling three timbres, under the $800 price range. While there may be limitations, these products are the result of ongoing refinement, innovation, and progress, stemming from Cayin's three decades of accumulated expertise and breakthroughs in vacuum tube technologies. Everyone can incorporate vacuum tubes into their amplifier, but utilizing them effectively and delivering an immersive audio experience is another. Cayin will live up to your expectations on the journey of high-fidelity vacuum tube applications.




N3Ultra Functional Diagram.jpg



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Cayin Stay updated on Cayin at their sponsor profile on Head-Fi.
Mar 1, 2024 at 8:40 PM Post #2 of 877

Introducing N3Ultra

Cayin N3Ultra - Unboxing

Exploring JAN6418 in Cayin N3Ultra and N3Pro

Connectivity of N3Ultra (USB Audio and Line Out)

Using PEQ in N3Ultra

Quick Access Bar in N3Ultra​

FAQ and Resources

N3Ultra Offical Launch
N3Ultra Product Page on Cayin Website
N3Ultra User Manual (PDF)
Classic mode of N3Ultra vs Triode mode of N3Pro
LED backlight for JAN6418 vacuum tube
Album Art display priority
PEQ is available with USB DAC mode



HeadFi impressions

Cheaplad: Apr 7, Apr 7,
alwass89: Apr 11, Apr 11,
Currawong: Apr 12,
mikaik: Apr 12, Apr 13, Apr 18, Apr 20, Apr 20
ToneDeafMonk: Apr 20, Apr 27, Apr 27, May 8,
kcsound777: Apr 20,
HeartByte: Apr 26,
jotaerre: Apr 26, Apr 27, Apr 27, Apr 29, May 9,
dakchi: Apr 26,
Zambu: May 8, May 10,

(upto Page 50)

v1.1 Firmware Update
v1.2 Firmware Update
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Cayin Stay updated on Cayin at their sponsor profile on Head-Fi.
Mar 1, 2024 at 8:41 PM Post #3 of 877
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N3Ultra will debut at CanJam New York 2024

Cayin will debut a new DAP at CanJam New York 2024. The N3Ultra is a long overdue update to the beloved N3Pro we launched all the way back in July 2020. The N3Pro surprised the Personal Audio community when we migrated the key technology of the N8 flagship DAP to our entry-level DAP within a year. Now we are doing this again, the N3Ultra is the second portable product in the Cayin lineup embracing the Gen3 Vacuum Tube Audio Circuit. With the choice of two tube timbers, and when the tube timbers are available to all analog outputs including but not limited to line out, the useability of the vacuum tube installation is expanded to a different horizon.

The N3Ultra used a pair of vintage NOS Raytheon JAN6418 in the tube timbre circuit. I have written some explanations about this military-grade miniature pentode vacuum in the N3Pro thread, if you are unfamiliar with miniature vacuum tube applications in the HiFi industry, you can check out our previous discussion HERE and HERE. Unlike the N3Pro, the JAN6418 tube timbre is now applicable to all FOUR analog outputs, namely the 3.5mm single-ended phone out, 4.4mm balanced phone out, 3.5mm single-ended line out, and 4.4mm balanced line out.

We have sent 3 sets of N3Ultra engineering samples to MusicTeck, If you are attending CanJam New York, please make sure you drop by MusicTeck's booth at B5-B8 to check out the N3Ultra DAP. The N3Ultra will be available by early April 2024, and we shall announce the retail price and provide full specifications and technical details of the new DAP by the end of March. I'll try my best to collect some preliminary information by next Thursday, so please subscribe and stay tuned.

Update before CanJam New York 2024.

Gen3 Vacuum Tube Circuit

This is our second DAP using JAN6418. The N3Pro was our first attempt and we have spent a lot of effort to install a pair of JAN6418 into a relatively compact DAP chassis. Unfortunately, we need to accept the following two limitations at the 2020 implementation:
  • JAN6418 is a Subminiature Pentode tube; we need a pair for the stereo circuit, a set of 4 for the balanced circuit. Since we can only install a pair of JAN6418 in N3Pro, the tube timber circuit can only facilitate single-ended phone out, the balanced phone out is solid-state only.
  • While we have passed down the Suspension installation technique from N8 to N3Pro, the filament of JAN6418 is a lot more sensitive to vibration when compared to the LED filament in Nutube, so the N3Pro is optimized for some scenarios but still suffers from ringing in other scenarios such as knocking on DAP, holding the DAP and then place it on a table or knocking on the table when DAP is placed on it.
With 4 years of portable vacuum tube R&D in our arms (since N3Pro) and the Gen3 Vacuum tube circuit after N30LE, we have improved the JAN6418 implementation by

1. Anti-shock Anti-vibration Installation

A newly designed custom-built shock absorption silicon housing that enables vertical suspended mounting. We incur this design from N8ii and provided significantly improved shock and vibration absorption. You can now shake it, tab on it, and even run around with it, the ringing effect is very minimal even with sensitive IEM. Make sure you try this in CanJam New York if you have the opportunity.

The 2024 version JAN6418 installation involved a custom-designed CNC-machined center frame, revised shock absorption silicone housings that provided better protection to each JAN6418 independently, and a “screwless” vertical-mounted installation.




2. Balanced phone output with two JAN6418

How can this be done? This is technically impossible, so we cheated. The DAC circuit and headphone amplification circuit of N3Ultra are fully differentiated but the timbre circuit, since we are using a pair of JAN6418 only, is singled-ended. We need to perform Balanced to Single-end before the timbre circuit, and Single-ended to Balanced after the timbre circuit. While N3Ultra is not a fully differentiated design from source to output, we have included some serious engineering to handle the correction properly. We are so confident that we even explain the constraint in advance.

Can we install four JAN6418 into N3Ultra to achieve a genuine fully-balanced design? This will involve more space and we can easily achieve that by increasing the width of N3Pro by 10mm. Unfortunately, using a quad-set of JAN6418 will consume more power, shorten the duration, generate more heat, and increase background noise, those are the real problems that stop us from using four JAN6418 in U3Ultra.

3. JAN6418 as Voltage Amplifier

The N3Pro employs JAN6418 as a buffer in its timbre circuit, it offers beautiful tube sonic characteristics to single-ended phone output. The Gen3 Vacuum Tube Circuit delivers a fuller tube sound to both single-ended and balanced phone out and lines out of the DAP, and we need a stronger output from the timbre circuit to achieve this goal, the JAN6418 is now connected as a low gain voltage amplifier in N3Ultra and we added a FET buffer immediately after the JAN6418 to enhance the output. Last but not least, since JAN6418 is a Pentode tube, we can connect it in triode and ultra-linear modes and use them as Classic and Modern tube timbre respectively. If you have heard the dual tube timbre of N30LE, you’ll be amazed that this is a simple circuit design that can achieve a similar dual timbre effect cost-effectively.

DAC circuit

The N3Ultra uses two pieces of AK4493S from AKM as DAC. A powerful FPGA has enabled the DAC can decode up to 32bit 768kHz in PCM, and 22.5792MHz (DSD512) in DSD.

Parametric EQ

This is a feature that has been on our To-Do List for several years. Yes, we heard you, and late is better than never.

We are still working on the PMEQ UI so the final control might be slightly different from the screen photo I showed below. You can add up to FIVE bands in the PMEQ section, each band is equivalent to a digital filter that enables you to shape the sound output of the DAP. To properly specify the characteristic of each band (filter), you need to specific

  • Frequency: the center frequency that you want to apply the adjustment in each band (filter)
  • Q: the ratio of center frequency to bandwidth, and when you fix the center frequency, then bandwidth is inversely proportional to Q, meaning that as you raise the Q, you narrow the bandwidth.
  • Gain: control the aptitude (boost or cut) for the center frequency specified in each band (filter)
  • Type: Choice of three types: Low Shelf, Peaking, and High Shelf
  • Enable or Disable a particular band, this will allow you to hear the difference of one particular band (with or without) specifically.
The Low shelf is typically the left-most (bass) frequency that you want to adjust, and the High shelf is the right-most (treble) frequency that you want to achieve, and the remaining bands should defined as peak type. The low-shelf filters and high-shelf filters act like a Low pass filter (LPF) and a high pass filter (HPF) respectively, but shelf filters can be used for boosting and cuts in the gain setting, while the pass filters can only be used for cuts.

As you set up the bands, the implication of each set will be stimulated in the FR graph above the band controls. This will help you to visualize the effect of your PMEQ settings.




System Configuration

The N3Ultra is powered by a Snapdragon CPU and operated under Android 8.1. While the system hardware is capable of running common music-related applications, the JAN6418 vacuum tube is extremely sensitive to wireless interference. We can’t quantify the difference between JAN6418 and, for example, the KORG Nutube 6P1 scientifically, but saying the JAN6418 is 10 times more sensitive is a conservative guess in our experience, and yet Cayin is probably the most experienced team on this issue in the portable audio industry. As a result, we make the N3Ultra puritans DAP without Wi-Fi or Bluetooth capability.

Can we include a WiFi feature and direct our users to use Wi-Fi while the DAP is not playing back? Yes, been there, and done that with the original N8, we received lots of user complaints over the years, and occasionally returned machines for warranty and repair service simply because users forgot to turn off the WiFi after turning on the WiFi "accidentally" or after the OTA firmware update.

Can we remove the WiFi feature and keep Bluetooth for wireless DAC? Yes, been there, and done that with the N3Pro, and we received user complaints that their sensitive IEM can’t use the wireless DAC features because of Bluetooth interference, in their opinion, when we provide the feature, we have the responsibility to make it workable for everyone.

From a business perspective, we want to sell more N3Ultra, and adding streaming support is the way to go, especially when we have the hardware and operating system to do just that. This is a tough decision because we are limiting streaming support through USB DAC only, but this is our choice to become a responsible brand. If we can’t provide noise-free streaming, we better take that feature away and make sure the JAN6418 timber circuit is performing satisfactorily.

Price, Date, and Availability

The MSRP of N3Ultra is US$529, and the DAP will be available by the second week of April 2024. The actual available date in your local shops might vary as they are subject to logistic and local sales arrangements. We shall host an official livestream session in Mainland China on the evening of 28th March 2024, providing full specifications, functional diagrams, and technical/engineering details of N3Ultra, please mark these dates if you are interested in the N3Ultra.
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Mar 1, 2024 at 9:19 PM Post #4 of 877
What is the expected price?
Mar 1, 2024 at 11:34 PM Post #8 of 877
This looks VERY interesting. I am looking for a "new' portable high quality DAP---have the Cayin N6 II-
This may just be what I want---portable tube and nice. IF the price is reasonable--I'm in. :)
Same here - looking for a new portable DAP
Mar 2, 2024 at 12:41 AM Post #10 of 877
Hopefully better SOC for more usable GUI? :pray:
Still love my original N3Pro...
Mar 2, 2024 at 1:17 AM Post #11 of 877
embracing the Gen3 Vacuum Tube Audio Circuit. With the choice of two tube timbers
Yes, yes YES!!!

That's what I like to see
Mar 2, 2024 at 6:21 AM Post #14 of 877
Very interesting I love my N3pro hope there's no 20,000 song limit this time.

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