Xiangsheng DA-02AII Dual-Core 1794 DAC Headphone Amplifier and Preamplifier with Bluetooth

I. Product Overview:
1. Features 4 inputs: USB, Coaxial, Optical, and BNC (the BNC port is replaced by a Bluetooth module if installed).
2. Includes two sets of RCA outputs—solid-state (op-amp based) and vacuum tube-based—allowing for versatile connections to either tube or solid-state amplifiers to achieve different sound signatures. Also features a dedicated headphone amplifier output.
3. Constructed with a brushed aluminum alloy front panel and a powder-coated thin steel chassis, providing excellent shielding.
4. Equipped with an internal toroidal transformer power supply, rather than an external switching power adapter.
5. True separation of digital and analog sections: utilizes independent transformer windings, separate rectification and filtering, and multi-stage voltage regulation for each section.
6. Powered by dual PCM1794A DAC chips, a CS8416 receiver, a CD2256 electronic volume controller, and an SGM4809 headphone amplifier. The CD2256 is a CMOS-based chip that uses an internal resistor ladder for volume control, ensuring high channel separation, low distortion, long lifespan, and noise-free operation. The SGM4809 delivers an output of 158mW into 16 ohms and includes comprehensive protection circuitry as well as a shutdown mode.
7. Op-amps: 2x OPA1612AIDRGR and 1x OPA2604AU. Vacuum tube: 1x 6N3 tube. 8. Optional Bluetooth upgrade (available for an additional fee): Features a Qualcomm QCC3084 module with support for lossless, high-definition formats such as LDAC and aptX-HD.

II. Product Specifications
Dimensions: 260mm (W) x 167mm (D) x 55mm (H) (excluding knobs, feet, and connectors)
Frequency Response: 20Hz–30kHz
Signal-to-Noise Ratio (SNR): Standard output: 110dB; Tube output: 90dB
Harmonic Distortion: Standard output: <0.001%; Tube output: <0.1%
RCA Output Level: 2000mV
Dynamic Range: 120dB
Input Impedance: 5Ω
Output Impedance: 600Ω
Weight: Approx. 4kg