D3 PRO introduction

D3 PRO inherits the D3 display and shell shape, and is black. It is a decoder and also a TPA3255 PFFB amplifier.

1、Hardware configuration
Decoding core: AKM AK4493S DAC chip, supports PCM 768kHz / DSD512 native hardware decoding

Amplifier module: TI TPA3255 PFFB (pure feedforward feedback architecture)

Digital interface: XMOS XU316 USB audio solution, supports ultra-low latency asynchronous transmission

Bluetooth chip: Qualcomm QCC3084, compatible with aptX Lossless / LDAC / LC3 and other high-definition encodings

Tone: NJW1194 electronic volume chip, supports ±10dB bass and treble adjustment

2、Input interface
Digital input

USB (Type-B USB1: PC/mobile phone decoding; Type-A USB2: U disk direct reading)

HDMI ARC (TV audio return)

Optical fiber/coaxial (SPDIF, supports 24bit/192kHz)

Analog input

RCA (input/output multiplexing)

Wireless input

Bluetooth 5.3 (aptX Lossless transmission, delay <50ms)

3、Output interface
Main channel: stereo output 

subwoofer :subwoofer interface (40-200Hz adjustable,)

RCA multiplexing: transfer to pre-stage output in non-input state (sound source sharing mode)

4、Working mode

AK4493S -> OP Amp-> NJW1194 ->  OP Amp*2 -> TAP3255

F  : NJW1194  Front end

B：NJW1194  Backend 

D-F mode 

Decoding source from NJW1194 front-end output, TPA3255 power is disconnected, tone/volume is invalid

D-B mode

Decoding source from NJW1194 back-end output, TPA3255 power disconnected, tone/volume adjustable

A-F mode 

Decoding source from NJW1194 front-end output, TPA3255 power on, tone/volume invalid

A-B mode

Decoding source from NJW1194 back-end output, TPA3255 power on, tone/volume adjustable。

In short：When RCA is not used as input, it is output. As output, the sound source is mode shared.