SINGXER SA-2 Headphone Amplifier

The Singxer SA-2 is positioned as a high-end headphone amplifier and preamplifier, fully balanced and featuring pure Class A architecture. Designed for audiophiles and users of high-performance headphones, it succeeds the highly regarded SA-1 by offering increased power and control.

Singxer SA-2: Design and architecture

Inside the chassis, Singxer has completely redesigned the power supply, circuit topology, and thermal management: a copper block and aluminum alloy heat sink ensure better heat dissipation, guaranteeing reliability and consistency during extended listening sessions. The SA-2 is a fully analog device with no audio microcontroller, which limits digital interference and prioritizes pure sound reproduction.

In terms of amplification, the Singxer SA-2 uses a four-channel independent and discrete pure Class A circuit. This purely analog amplification and its control circuits eliminate EMI interference from digital control, ensuring faithful sound reproduction.

ROHM's ultra-low noise differential input transistors in a matched SMD design ensure high consistency. The other audio transistors used offer exceptional linearity for superior performance. The power supply uses high-current, ultra-low noise LDO regulators.

The final output stage uses multi-stage current amplification, similar to the architecture of high-power amplifiers. Each channel uses two pairs of ON Semiconductor medium-power transistors with a current of 4A in a parallel output configuration, ensuring sufficiently low internal resistance and high output power. This design ensures stable performance, even during high dynamic range transitions.

The SA-2 also benefits from a comprehensive protection system against overcurrent, overload, overheating, short circuits, DC protection, power-up delay, and instantaneous disengagement of the output relay during shutdown.

Singxer SA-2: Impressive performance

The power gain is significant: up to 10W at 32Ω and 15W at 20Ω, allowing you to drive both high-impedance headphones and low-impedance models. The distortion level is extremely low: THD+N measured at -117dB at 1kHz for a load of 32Ω at 8W, and a signal-to-noise ratio (SNR) and dynamic range greater than 146dB (A-wt). The advertised bandwidth ranges from 20Hz to 80kHz ±0.1dB.

Singxer SA-2: Connectivity and adaptability

The SA-2 offers balanced (XLR) and single-ended (RCA) inputs, as well as multi-format headphone outputs: 4-pin XLR connector, balanced 4.4mm jack, and single-ended 6.35mm jack. It also has preamplifier outputs (XLR/RCA) and a “GND/LIFT” switch to eliminate ground loops in complex systems. The output impedance in Low-Z mode drops to 0.15Ω in balanced mode or 1.1Ω in unbalanced mode, ensuring very firm control of demanding headphones.

Singxer SA-2: Ergonomics and usage

The front panel of the device remains simple and functional, with a high-end ALPS potentiometer for smooth and precise volume control. The 234 x 170 x 46 mm format and aluminum chassis reinforce the impression of quality and robustness, while facilitating integration.