The X26III uses two high-end ESS ES9039SPRO chips for digital-to-analog conversion, one for the left channel and one for the right, each with its own independent power supply. These premium chips enable conversion of PCM up to 32-bit/768 kHz and DSD up to DSD512. NOS mode is also available.

The X26III also features a high-performance digital filtering solution developed specifically for digital audio on the Analog Devices SHARC DSP platform. Its main purpose is to reduce aliasing noise within the digital audio frequency range. This filter improves sound quality by increasing the resolution of the raw digital audio signal and shaping its noise. The anti-aliasing algorithm used in the program, along with high-precision 64-bit floating-point operations, ensures crystal-clear audio reproduction.

The X26III uses a GCLK clock module and a high-performance frequency synthesizer that employs advanced PLL (phase-locked loop) technology to ensure clock stability and accuracy. This module is designed to support both a locally generated clock signal and an external 10 MHz clock, providing a high-quality and flexible clocking solution.

The output low-pass filter of the ES9039SPRO DAC chips is built using Class A discrete circuits. This solution allowed Gustard to fine-tune the filter as much as possible during the design phase, resulting in a warm, natural sound free from noise and distortion.

The X26III is based on the CelWare 3.x system. This operating system is built around a Linux kernel optimized for audio signal input and output, and is compatible with Roon Bridge, AirPlay, HQPlayer NAA, UPnP, mConnect, BubbleUPnP, Spotify, and QQMusic protocols. The different protocols can be easily activated or deactivated in your PC browser by entering “//x26.local”.

The X26III also features a USB XMOS XU216 interface, which supports signals up to PCM 768 kHz and DSD512.