U18

About the U18

The Gustard U18 is a USB digital-to-digital converter (DDC), not a DAC or analog audio interface. It converts USB audio to multiple digital formats, including coaxial S/PDIF, AES/EBU, optical Toslink, and configurable LVDS I2S over an HDMI-style connector. It uses an XMOS XU216 USB interface, galvanic USB isolation, a Gustard K2 clock synthesizer, dual Accusilicon AS338 oscillators, and an Altera MAX II CPLD for digital signal and I2S timing management. The U18 accepts an optional external 10 MHz reference clock and provides a word-clock output. The I2S connector is not standard HDMI audio/video; compatibility depends on the receiving device's I2S pinout. Published listings and the manufacturer manual remain available, but current official production status is not clearly documented. It should therefore be treated as a legacy or possibly discontinued model rather than definitively confirmed as no longer manufactured.