Cen-Grand 9i-90SA Pro “Lark” Second Generation

A variety of advanced technologies and solutions such as USB isolation technology were integrated, such as ESS 9039Pro  DAC chip work in two-channel parallel connection, etc. The audio quality especially headphone amplifier performance is excellent.  It will get a good effect in driving mainstream headphones such as HD800S and T1-II.

9i-90SA Pro has many functions and performs well on the adaptability of the headphones.  There are not only four types of output modes for adapting many kinds of headphones but also different output circuits for high and low-impedance headphones.  As a headphone Hi-Fi product, it is good at both performance and function.

The 9i-90SA Pro ” Lark ” consists of the following parts:

1. USB interface:  XMOS second generation XU208 + FPGA digital processing module,  isolation technology is used to isolate noise from the computer.  Support for NativeDSD512  and PCM384 input.
2. CT5302 + ESS 9038Pro DAC chip: The SPDIF receiver has three interfaces: coaxial, optical, and AES, supporting PCM 24bit/192KHz and DOP (DSD64) inputs.
3. Headphone amplifier: It has a 6.35 unbalanced interface, 4-pin XLR balanced interface and 4.4 balanced interface.  It has four output modes: Normal, BTL, Active Ground and Parallel.
4. Pre-Amp consisting of discrete components: It can be used as a pre-amp, the input interface is RCA and XLR,  with infrared remote control.
5. Power supply and display system

An ESS 9038Pro DAC chip is used.  There are 8 internal DAC in the 9038Pro chip.  Most of DAC which used 9038Pro chips only use one of them.  The others are idle.  The mode of multiple DAC channel parallel has many advantages, but getting good sound and heating is not easy.  The 9i-90SA Pro works in 2-channel parallel mode. 

There are 4 modes of connecting to the headphone. Each mode has its characteristics,  and the difference is very obvious.  This function is very useful for the user because he can choose the most suitable mode for his headphone.  Under normal conditions high-impedance and high-quality headphones are suitable for Balanced (BTL) mode,  in this mode the headphones can fully be driven by Amp.  When your headphones are easier to be driven, you can choose parallel or Active G mode to drive them, as well as Normal mode.  Here,  I would like to introduce what is the “virtual ground(Active G)” mode.

Usually, the positive terminal of the headphone cable should be connected to the positive output, and the negative terminal should be connected to the GND.  If we make the input terminal of the amplifier to GND, its output will get a 0 level, which is the same level as GND.   At this time if the negative terminal of the headphone is connected to this 0 level, it is equal to connected GND.  But this is not the real GND, only simulated GND,   that is to say, “virtual GND”(Active Gnd).   This kind of connection can get a more unique sound,  the listening experience is warmer and softer, more suitable for listening to human voice or string.   In short,  the “virtual GND”(Active G) mode provides users with an effective tuning method that increases adaptability and entertainment.

The second generation of XMOS is the latest XMOS solution which is faster than last.  Isolation technology enables blocking between the computer and 9i-90SA Pro.  The ground wire is not connected so noise was almost completely isolated from the computer.  This feature is very effective because there are a large number of switching power supplies inside the computer that generate a lot of noise which can interfere with the analogue circuit, and audio performance will be degraded.  Isolating these noises can significantly improve the purity of the sound.

The LPF is a balanced structure and a high-performance OP Amp LM49720  was used. The analogue output section is composed of a discrete device architecture which has been carefully tuned to correct the sound.  The volume control chip is PGA2311 which is controlled by MCU and the volume range is -70db~0db.  Its common volume has been optimized, volume adjustment and listening habits are more coordinated and there are reliable protection measures.

The headphone amplifier uses a current feedback circuit.  The technology of the headphone amplifier is simple and the key is the adjustment.  Drawing on extensive experience in hifi systems, we have achieved very good results in designing of the “Lark” headphone amplifier.  It not only has strong driving ability but also sound balance, clear and delicate, and a strong sense of space.  You can listen for a long time as well as forget the existence of headphones just like listening to the big HiFi system.

The display is OLED.  

9i-90SA Pro is a DAC which with coaxial, optical, AES and other digital input interfaces.  It can be used to upgrade a CD player or as an external DAC for digital players in your audio system. It has a volume adjustment function.

It is a fully balanced pre-amp with RCA/XLR input and output interface.  Active speakers can be connected to it for building desktop hi-fi systems. You can also use it as a preamp to connect to your power amplifier to build a large hi-fi system.
It is a pure headphone amplifier. It drives both high and low-impedance headphones with good musical expression.

It is an advanced USB DAC with the second generation of XMOS. The driver is a customized version and is a good choice for pc hifi players.

The most common use of the 9i-90SA Pro is: Connect this unit to your computer via a USB cable, and the music data is transferred to the unit. USB supports DSD512/PCM384. The computer player is very compatible and powerful so it can play music in any format. 

The 9i-90SA Pro’s headphone amplifier has good quality and can drive mainstream high-end headphones.  Its two output circuits enable it to adapt to both high and low-impedance headphones.  Four output modes make the 9i-90SA Pro has good adaptability to various headphones. Whether 600-ohm high-impedance headphones or 30-ohm  it can be well adapted.