Singxer SDA-6 PRO2: Balanced DAC based on AK4499EX

Singxer SDA-6 PRO2 , the second version of SDA-6 PRO, is a high-precision balanced DAC. It has many improvements compared to the first version:

• For digital-to-analog conversion, the SDA-6 PRO2 uses two AKM AK4499EX DAC chips combined with an AK4191 digital filter.
• The USB interface crystal oscillator uses a femtosecond oscillator coupled with an internal constant temperature system to improve stability.
• The USB interface has been upgraded to the XMOS XU-316 third generation USB interface, supporting 32-bit 768 kHz PCM and DSD512.
• The power supply has also been upgraded to an ultra-low noise system that reduces low-frequency distortion
• Digital preamp supports volume control, analog gain up/down, screen brightness adjustment and screen-free playback

The Singxer SDA-6 PRO2 balanced DAC architecture delivers a level of audio reproduction that will leave you spellbound. It uses premium components selected for their audio performance. As mentioned above, its D/A conversion stage is based on two AKM AK4499EX DAC chips combined with an AK4191 digital filter. They support high-resolution streams up to PCM 32Bit 768 kHz and native DSD up to DSD512. The DSD stream operates in NOS (Non Over Sampling) mode without passing through the AK4191 filter to preserve the original signal as much as possible.

The USB interface is a XMOS XU-316 interface, and a dedicated AKM AK4118 chip is used to receive the SPDIF signal. In addition to these high-precision components, an STM32 microcontroller is responsible for efficient data processing, and a Xilinx FPGA handles clock control and digital audio processing.

As for the output circuit of the SDA-6 PRO2, it uses 4 discrete Class A output channels with a DC balanced architecture without negative feedback loop. The USB input oscillator uses the CCHD-957 femtosecond oscillator for low jitter, combined with 4 independent ultra-low jitter oscillators for the rest of the circuit. The analog stage uses Mundorf film capacitors for superior musicality.

The power stage uses a custom 40-watt O-type transformer with 4 independent output windings. In addition, the digital-to-analog conversion stage is powered by a new low-noise system (0.3 µV). An internal switch provides selection of 115 or 230 VAC input voltage for the Singxer SDA-6 PRO2.

Specifications of Singxer SDA-6 PRO2:

• Product Type: Balanced DAC
• DAC chip: 2x AKM AK4499EX
• Inputs: 1x I2S LVDS HDMI (standard PS Audio output)/1x USB-B/1x Optical Toslink/1x Coaxial/1x AES/EBU/1x BNC/1x CLK (via BNC connector)
• Outputs: 1x XLR stereo balanced/1x RCA stereo unbalanced
• Supported sample rates: USB, I2S: PCM up to 32bit 768kHz, native DSD up to DSD512, DSD DoP up to DSD256/SPDIF, AES/EBU: PCM up to 24bit 192kHz, DSD DoP up to DSD64
• SPDIF input impedance: 75 ohms
• Input impedance AES/EBU: 110 ohms
• Output Levels (0dBFS): PCM: RCA 2.6V RMS, XLR 4.6V RMS/DSD: RCA 2.6V RMS, XLR 4.6V RMS
• Output Impedance: RCA: 22 ohms / XLR: 45 ohms
• Frequency response: 20 Hz – 20 kHz ±0.1 dB
• SNR: 131 dB (20 Hz – 22 kHz, A-Weighting)
• THD+N (1 kHz, 0dBFS): 0.00012% (-118 dB) @ fs=44.1kHz, PCM, 20Hz-22kHz, A-Weighting
• Dynamic (1 kHz, -60 dBFS): 131 dB @ 20 Hz-22 kHz, A-Weighting
• Channel Separation: >130dB @ 1kHz Total Supply Voltage: 115V-230V AC (selectable by internal switch)
• Dimensions (excluding feet and connectors): 262 x 220 x 46 mm
• Weight: 2.7 kg
• Black color