Cayin N8ii (Pre-Order)
1. Dual DAC Architecture
The N8ii is designed around a pair of ROHM BD34301EKV 32Bit Current Mode DAC chipset. The DAC chipset was announced back in February 2021, perfect timing to save our AKM-based project. The AKM fire was one of the hardest blows to our industry and Cayin began looking for a new DAC solution almost immediately.
Cayin is the first audio company to use the ROHM BD34301EKV in portable audio applications. Developing a new chipset from scratch is a lengthy and resource-intensive process. Our engineers have invested a lot of time learning, experimenting and tuning the supporting system for this new DAC chipset.
We developed 6 rounds of technical circuit boards to explore the potential and implementation options for the BD34301EKV.We collected massive raw data over I2S and compared it to numerous analog output data that we experimented with and cross-checked it with the ROM demo board to validate the improvements we made. We see a lot of potential in this chipset as it can be used in both the technical measurements as well as the listening impression is really outstanding.
To maximize the performance of the digital audio circuitry, our FPGA enhanced and reorganized the incoming digital signal and passed the audio bitstream to two BD34301EKV in mono mode. N8ii can decode up to 32bit/768kHz with PCM and 1bit/22.6MHz (DSD512) with DSD. It offers two low-pass antialiasing filters (PCM mode) and three DSD filters to fine-tune the sound signature.
A TOTL DAC requires TOTL support, and Cayin won't mess with our N8ii with less than settle for the exotic. We employed two femtosecond crystal oscillators with extremely low phase noise (-100dBc) to ensure high-precision, low-jitter digital reproduction.
We implemented a solid 2x2 current-to-voltage converter network as the high-current, low-noise output stage of the sonically excellent current-mode ROHM DACs. Last but not least, we built our circuitry with a 6-layer PCB to improve signal isolation, and we covered the entire digital audio circuitry with an aluminum heat shield to reduce background noise and interference on critical components.
2. Fully-Balanced Dual Timbre
Our Vacuum Tube/Solid State Dual Timbre feature rocked the world in May 2018. We solved the microphonic problem with innovative techniques, allowing for the first time a choice between vacuum tube and solid state timbre in a portable DAP.
Of course, when we started our N8ii project, one of the primary requirements was to improve the dual-timber capability to support a balanced output. The Dual Nutube implementation in the N8ii is even more demanding than in the C9 as we have to take care of a 5" OLED screen at the same time. Therefore we have to be very innovative in the placement of the circuits and components to fit everything in a compact handheld solution.
3 Fully Discrete Dual Output Mode
This is a unique feature only available in the N8 We change the headphone amplification operating voltage to match the output power , increase the power handling and the sonic signature of the circuit, and allow the user to choose between the standard P-mode and the high-output P+ mode via a pull-down menu.
We'll keep this feature in the N8ii, and better yet, we've moved the headphone amplifier circuitry to a fully discrete design. This will make the P+ mode in the N8ii very different from the standard P mode.
Four discrete components of Class-A and Class-AB modes to form a four-channel power amplifier circuit.
Volume control uses JRC NJW1195A four-channel precision analog volume control chip.
4. Power Supply
The N8ii uses a 3.8V 10,000mAh high-capacity, low internal resistance lithium-ion polymer battery. With different modes of operation and output, the longest operating time is about 11 hours (3.5 single-ended output, class AB, transistor, P-mode) and the shortest is about 8 hours (4.4 balanced output, tube, P+ mode, class AB).
The N8ii features a variety of output modes and modes of operation, allowing the user to make choices and achieve the best listening performance according to their needs. The N8ii's audio amplifier circuitry was designed using discrete components.
Using the experience we gained developing the N6ii E01, E02 and C9, and considering the characteristics of the N8ii battery, we manually paired and matched the TRIODE of each stage to ensure the accuracy of the bias current setting and the signal range of the triode gain.
This will help achieve sound changes through the different modes of operation of Class A and Class AB. We already reported on the differences between Class A and Class AB when introducing the N6ii E01 and E02. Many customers like the sound of the E01 very much, but at that time there were many limitations due to the framework of the N6ii and the output power was relatively low.
5. Heat Dissipation
We put a lot of effort into the structure of N8ii to improve heat dissipation. Not only because of the complex circuit design, but also because of Class A's low conversion efficiency and high power consumption. Class A's sound is vivid, full and very distinctive, and has been recognized by many audiophiles.
It would be a pity if it could not be realized because of heat dissipation and other problems. Therefore, in addition to the precise setting and tuning of the bias current, the question of how to make the thermal conductivity faster and more uniform is a big problem during development.
The housing of the N8ii is not made of copper or stainless steel, but of the magnesium-aluminum alloy commonly used in aviation. This is partly because of the low thermal conductivity of copper and stainless steel and partly because of the balanced considerations of size and weight.
- Two ROHM BD34301EKV DAC, 32Bit/768kHz, DSD512
- Balanced tube amplification paired with KORG Nutube 6P1
- Fully discrete balanced headphone amplifier
- Dual reinforcement mode (class A/class AB selection)
- Dual output mode: P (standard) and P+ (high power) mode
- High quality 3.5mm and 4.4mm line out
- Snapdragon 660, 6G RAM, 128G internal, 1xTF card (up to 1TB)
- Android 9, Google Player preinstalled, streaming ready
- DTA bypass Android SRC, Hi-Res playback with all applications