9i-90SA Pro （“Lark” second Generation ）DAC/headphone Amp/Pre Amp
9i-90SA Pro （"Lark" second Generation ) is simplified version of 9i-92SA III.
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 good effect in driving the 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 mode for adapting many kinds of headphones but also different output circuits for high and low impedance headphones. As a headphone hifi 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, support PCM 24bit/192KHz and DOP (DSD64) inputs.
3: Headphone amplifier. It has 6.35 unbalanced interface, 4-pin XLR balanced interface and 4.4 balanced interface. It has four output mode: 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 are used. There are 8 internal DAC in 9038Pro chip. Most of DAC which used 9038Pro chip only use one of them. The others are idle. The mode of multiple DAC channel parallel has many advantages but it is not easy to get good sound and heating is serious. The 9i-90SA Pro works in 2 channel parallel mode.
There are 4 modes of connecting to headphone . Each mode has its own characteristics, and the difference is very obvious. This funtion is very useful for user , because he can chooses the most suitable mode for his headphone. Under normal conditions high-impedance and high-quality headphones are suitable for Blanced(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 amplifier to GND, its output will get 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 connecte 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 isolating 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 analog circuit , audio performance will be degrade. 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 analog 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 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 headphone amplifier is actually simple and the key is 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, 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.
Use of 9i-90SA Pro
9i-90SA Pro is a DAC which with coaxial, optical, AES and other digital input interfaces. It can be used to upgrade 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 hifi systems. You can also use it as a pre amp to connect to your power amplifier to build a large hifi 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 : Connect this unit to your computer via a USB cable, 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 enables 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 headphone or 30-ohm it can be well adapted.
Maximum audio support specifications: Spdif input ----- PCM192
USB input ----- DSD512 PCM384
Dynamic range: 115dB
Signal to noise ratio: 115dB (A weighting)
Frequency response: ±0.4 dB (20-20KHz A weighting)
THD+N: -102dB (fs=96KHz /10KHz A weighting)
Pre-level gain: 4db (volume is 0db)
Output power: 1.5W (33 ohms distortion 0.5%) 0.5W (600 ohms distortion 0.017%)
Dimensions: 260mm * 85mm * 280mm (WHD)
Power supply: AC 220V-230V 50-60HZ (Fuse specification: 6.3A)
Gross Weight: 4.35kg