Singxer SA-2 Class-A Headphone Amplifier & Pre-Amplifier

The Singxer SA2 is the next-generation evolution of the acclaimed SA-1 V2. It is a high-performance, fully analog Class A headphone amplifier and preamplifier built around a completely balanced and discrete circuit architecture. Compared to its predecessor, the SA2 features a refined circuit design with lower output impedance and a dramatically increased output power, making it suitable for even the most demanding headphones on the market.

Balanced Design:-

As the SA-2 is a headphone amplifier with a fully balanced design concept, it has made the greatest optimization for full balance. Therefore, the best way to use it is : balanced input and balanced output, followed by single-ended input and balanced output.

SA2 Compared to SA1v2:-

Output power has been increased from 5.5 watts into 32 ohms on the SA-1 to 10 watts into 32 ohms , with a maximum output of 15 watts into a 20 ohm load . It supports headphones with a minimum load of 8 ohms.

Through circuit optimization, ultra-low distortion can be maintained even at high power output.

More efficient heat dissipation design, using copper block + aluminum alloy radiator design.

Reduced the impedance of the balanced headphone amplifier output port, enhanced the current driving capability, and provided greater thrust.

Optimized PCB routing, adjusted the DC bias design of the circuit, added DC servo design.

Added GND/LIFT mode switch.

Pure Analog Signal Path:-

With no digital control circuitry, the SA2 avoids any EMI interference that could affect the audio signal. High-performance ROHM input transistors ensure ultra-low noise and excellent linearity.

The output stage uses a multi-stage current amplification design, similar to what is found in full-size power amplifiers. Each channel is equipped with high-current ON Semiconductor output transistors for very low internal resistance and powerful drive capability.

To ensure safe operation, the SA2 includes protection against:

• Overcurrent
• Overload
• Short-circuit
• Thermal conditions
• DC offset
• Turn-on delay

To ensure compatibility with all headphone types—from sensitive IEMs to high-impedance studio models—the SA2 offers adjustable impedance and source selection via front-panel switches:

• Input Select: RCA / XLR
• Headphone Output Impedance Mode: LOW-Z (low resistance) / HI-Z (high resistance)

Output impedance on the pre-outs remains low for optimal matching:

• Unbalanced RCA: 22.5 Ω
• Balanced XLR: 45 Ω