The Sony RSX-GS9 is a high-resolution digital media receiver built for audiophile-grade car audio systems, featuring native DSD playback, a 32-bit ESS DAC, and no internal amplifier. Key Specifications and Features No internal amplifier : Requires external power amplifiers to run speakers. High-res file support : Plays DSD, FLAC, WAV, ALAC, AIFF, AAC, MP3, and WMA formats. Premium components : Uses an ESS ES9018S 32-bit digital-to-analog converter and a MUSES 8920E operational amplifier. DSEE HX upscaling : Restores compressed audio files to near high-resolution quality. Chassis build : Features a rigid, dual-layer design with a brushed-aluminum faceplate.Inputs, Outputs, and Connectivity Multiple USB ports : Includes two front USB ports and one rear USB port for digital device connections.Preamp outputs: Equipped with 5-volt front, rear, and subwoofer RCA connections. Optical output : Features a TOSLINK optical digital output to connect directly to external digital signal processors (DSP). Wireless streaming : Built-in Bluetooth with LDAC support and NFC one-touch pairing.