This Gustard U18 USB digital interface offers a high quality design, ensuring excellent performance and accurate sound reproduction. The input point of the U18 is a second generation XMOS XU216 USB interface with 16 cores. The audio signal is fully isolated by a 200Mbps isolator to eliminate interference. It is then processed, corrected if necessary and jitter is removed by an Altera MAX II CPLD. To generate an extremely accurate clock signal, the U18 uses two Accusilicon AS338 oscillators with a jitter of only 38fs and a Gustard K2 ultra low noise clock synthesizer. Moreover, the power supply of the clocks is done by a LT3045 linear regulator with a noise level of only 0.8µVrms. The power supply stage uses a large custom toroidal transformer, optimized for audio use.
For its audio outputs, the Gustard U18 offers Toslink Optical, Coaxial, AES and I2S via HDMI. On this last output, it supports high-resolution audio streams up to PCM 32bit 768kHz and DSD512. Moreover, the I2S pinout is configurable in 4 modes to adapt to most devices on the market. Finally, we note the presence of an MCLK input and WCK output on BNC.