Ustars Audio C39 2G Hifi Audio Bridge with Pure Linear Power Supply and OCXO for ROON Bridge Airplay

Ustars Audio C39 2G Hifi Audio Bridge with Pure Linear Power Supply and OCXO for ROON Bridge Airplay

Advantages:
* Global femtosecond clock synchronization
* SFP and LAN inputs
* Built-in OCXO
* Built-in PHY
* Supports external 10MHz clock
* Native USB output
* 4-layer PCB substrate design
* Multi-channel UV low-noise voltage stabilization
* Customized high-quality base plate

Features:
Clock System Enhancement
The Raspberry Pi CM4 core module uses a low-precision passive crystal oscillator as its clock signal source, resulting in lower clock signal quality. When the CM4 module is applied to the C39, the original passive crystal oscillator is removed. We replace it with a high-quality, precise clock signal generated from an Oven-Controlled Crystal Oscillator (OCXO), outputting 54 MHz and 25 MHz signals to the CM4 core module. The OCXO provides high precision and stability. The clock upgrade significantly improves the bus clock quality, enhancing the overall sound with better extension, clarity, and detail.

Native USB
As we know, all USB ports on the Raspberry Pi 4B are converted from the PCIe interface, which results in non-native USB and limited output quality. However, the C39 bridge uses the CM4 core module, which directly outputs high-quality native USB signals from the CM4 CPU without conversion, reducing signal loss and minimizing interference. The native USB connection to your decoder's USB input provides superior bridge functionality, delivering crisp, delicate sound with a wide soundstage and precise positioning. The performance of the C39 is clearly superior to the USB output of the Raspberry Pi 4B.

Precise Base Timing
The C39 is equipped with a high-end OCXO that provides precise clock signals for the entire system. By incorporating a 10M clock signal, it greatly enhances the clarity and transparency of the sound, resulting in an expansive soundstage and precise positioning.

Femtosecond-Level Clock
The C39 features a professional-grade SI5340 clock synthesizer. Its output jitter is as low as 90 femtoseconds (fs), providing the entire system with a high-quality, globally synchronized clock signal. Its clock performance is far superior to typical ps-level clocks, ensuring exceptional accuracy and stability.

External 10 MHz Clock Input
The C39 provides a clock input, allowing you to connect your high-quality synchronized clock for performance enhancement. When the switch is set to the "EX" position, the C39 will use the external input clock, and the built-in OCXO will power off to reduce interference, ensuring better signal quality.

Dual USB Ports
* The C39 is equipped with two USB ports. The USB 2.0 port directly outputs high-quality native USB from the CM4 core CPU. The USB 3.0 port provides output through the high-fidelity PCIe-to-USB 3.0 chip, uPD720202. The uPD720202 is powered by a pure linear regulated power supply and enhanced with a synchronous clock, significantly improving its output quality.
* Both USB ports can be used to connect a decoder. They exhibit slight differences in sound characteristics—for example, the USB 2.0 port delivers a clean sound with a stronger analog feel, while the USB 3.0 port offers better micro-dynamics and improved resolution. The dual USB ports also provide greater convenience for using USB system drives such as Diretta.

LAN and SFP Network Interfaces
The C39 provides a standard LAN (RJ45) port for wired network connectivity. The SFP port offers a more advanced setup—when used with compatible fiber optic modules and switches, it enables optical isolation for enhanced performance. The built-in synchronous clock PHY further improves sound clarity and transparency.

Software Support
The C39 network bridge is powered by the Raspberry Pi Compute Module 4 (CM4), featuring the same core as the Raspberry Pi 4B. In theory, any system compatible with the Raspberry Pi 4B can run on the C39. Based on our actual tests, commonly used software such as Volumio, Ropieee, Moode, and PiCorePlayer are also fully compatible with the C39.

When shipping, we will pre-install the official version of the Ropieee system. This system offers excellent sound quality, rich features, and ease of use. Once installed and set up, users generally do not need to make any further adjustments. Simply connect it to a network, and the C39 will support the following functions:
* HQPlayer NAA
* Roon Bridge
* UPnP
* AirPlay (for Apple systems)
* Squeezelite (for Daphile)

If you need us to install other systems, such as PiCorePlayer, Volumio, or Moode, please contact us before making your payment.

Special Reminder:
1. Although the C39 is well-designed, performs excellently, and offers a full range of features, it is primarily suited for users with experience and knowledge of Raspberry Pi. Our after-sales support is limited to hardware issues only. Users without experience are advised to carefully consider whether this product is suitable for them.
2. The C39 is a relatively sensitive device, so it is recommended to pair it with quality equipment and cables to enhance the overall performance.

Specifications:
1. Input:
* RJ45 port / Auto-negotiating 10M/100M/1000M x1
* SFP port / 1000M (Non-auto-negotiating. Can be set to 100M) x1
   • The SFP port is compatible with 1.25G SFP optical modules, RJ45 expansion modules, and some 10G optical modules.
   • Note: The machine does not support WIFI and Bluetooth.

* 10MHz clock input BNC connector / Impedance: 50R x1
    • Supports most sine or square waves with 0.5-3.3Vpp levels.

2. Output:
* Native USB2.0 x1
* USB3.0 x1
   • Supported Specifications: PCM: 44.1KHz~768KHz/32-bit and DSD: DSD64/128/256/512 (Native DSD)

Special Reminder:
* The outputs listed above require your decoder to support these specifications.
* When using the USB output to connect to a decoder for Native DSD decoding, the decoder's USB input must support for Linux DSD Native.
* The USB output interface should not be connected to USB devices drawing more than 300mA of current. It is only suitable for connecting to a decoder's USB input or other low-power USB devices.

3. Power Specifications:
* Input: AC 220V
* The included power cable is a standard Chinese three-prong plug. Other plug standards are not currently provided. If needed, please replace the power cable with one that suits your requirements.
* Since the device does not have an adjustable power supply voltage, if you need 110V, please contact the seller before making your payment.
* Power Consumption: <20W

4. Chassis Specifications:
* Dimensions: 230MM x 55MM x 160MM (excluding protruding parts)
* Net Weight: Approximately 2.5Kg

Package Included:
* 1 x Hifi Audio Bridge
* 1 x AC220V CN Power Cable
* 1 x USB Programming Cable

Packaging Details:
* Packaging Dimensions: 300MM x 150MM x 300MM
* Packaging Weight: Approximately 3.15Kg

Note:
* Please note that only the CN power cable is available.
* The device is powered by a pure linear power supply and generates a significant amount of heat during operation. Please ensure the machine is placed in an open and well-ventilated environment.