This is a balanced USB DAC using AKM's DAC AK4497S. It was purchased for trial listening and used for about 20 hours. Operation has been confirmed. Thank you for your consideration. App-controlled smart operation - Seamlessly integrates with the TOPPING Home app, allowing real-time control of smartphone input/output, EQ, and volume. Premium AK4497S DAC chip - Equipped with AKM AK4497S VELVET SOUNDTM DAC, realizing rich details, natural tone, and high-precision acoustic reproduction. High-resolution USB audio performance - Equipped with XMOS XU316. Supports DSD512 (native), DSD DoP, and PCM up to 768kHz/32bit, realizing high-resolution playback. High-precision PEQ and smart digital input - Features a built-in 10-band parametric EQ (with independent L/R tuning) and intelligent optical input functionality with automatic S/PDIF and ADAT detection. Ultra-low noise and clean signal design - The FPGA+PLL TopSync circuit (JitterNull technology) effectively suppresses jitter, delivering a cleaner and more stable digital audio signal. Wireless and flexible system integration - Supports LDAC, aptX Adaptive/HD Bluetooth, switchable DAC/preamp mode, RCA and TRS outputs, selectable output levels, touch controls, and remote support.