Digital-to-analog conversion is handled by ESS's high-precision ES9039Q2M DAC chip. Through its XMOS XU316 USB interface, the ZD3 can process PCM signals at up to 32-bit/768 kHz and native DSD512.

Other key components include the Qualcomm QCC3031 Bluetooth chip and factory-installed LME49720 operational amplifiers, while the DIP8 sockets allow the sound signature to be customised: in addition to the LME49720, compatible options include the NE5532, MUSES02 and SS3602.

Fosi Audio's proprietary I/V conversion circuit and fully balanced signal path are designed to reduce noise and crosstalk. High-precision wafer resistors and low-temperature-coefficient capacitors help minimise signal-processing errors and provide more accurate balance between the left and right channels.

Each of the two XLR output channels features its own LME49720 operational amplifier and a separate pop-noise suppression circuit. With both balanced XLR and unbalanced RCA connections, the ZD3 can be easily integrated into existing systems.

The ZD3 is Fosi Audio's first DAC equipped with an HDMI ARC input. It receives digital audio directly from the ARC connection of a compatible television or monitor, allowing sound from the TV, game consoles and other sources connected to the display to play through the HiFi system.

In HDMI mode, the CEC function supports synchronised power control between the ZD3 and the source device, as well as volume adjustment using the television remote control. The device does not support HDMI eARC.

Built around the Qualcomm QCC3031 chip, the Bluetooth connection provides convenient wireless music playback from a phone, tablet or computer. In addition to SBC and AAC, it supports aptX and aptX HD codecs, with a maximum received signal resolution of PCM 24-bit/48 kHz.

The included external antenna helps provide a more stable wireless connection, while Bluetooth mode can be selected using the device's control knob or the dedicated BT button on the remote control.

With Bypass mode disabled, the ZD3 operates as both a DAC and a preamplifier, allowing the volume to be adjusted using the front control knob or the remote control. This is a practical solution for active speakers or a directly connected power amplifier.

The Bypass switch on the underside of the device enables pure DAC mode. In this mode, the signal bypasses the internal preamplifier section, the output level is fixed at 0 dB, and the volume must be adjusted on the connected preamplifier, amplifier or active speakers.

The circular OLED display shows the active input, current sampling frequency, PCM, DSD or Bluetooth format, volume level and mute status at a glance.

The large front-panel control knob performs several functions: it can be used to power the device on, adjust the volume and switch between inputs.

The included infrared remote control lets you select the USB, HDMI ARC, coaxial, optical or Bluetooth input from your sofa, as well as adjust the volume and activate mute.

The bidirectional 12 V trigger connection automates system power control. Through the Trigger Out connection, the ZD3 can control the power and standby status of a connected power amplifier or active speaker.

Conversely, a source device connected to the Trigger In input can control the power and standby status of the ZD3. Its matching design language and proportions with the ZA3 power amplifier make it possible to create a cohesive, space-saving Fosi Audio system.