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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.







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