The Ultra Desktop DAC
The organic and natural sense of ease you experience when listening to the Ultra Desktop DAC belies the exotic, novel, and strikingly complex technologies found in the ESS Technology Sabre 9018 DAC. This exquisite audio part delivers state-of-the-art performance in numerous measures using several patented, or patent applied for techniques.
Digital inputs are switched and converted to an I2C digital signal in the Cirrus Logic CS8416 digital receiver; this device also significantly reduces incoming jitter. Once in the DAC input section, the digital signal edges are cleaned up using a digital delay line and, rather than re-timing or decoding the embedded word clock, data is “time stamped” and sent to the oversampling DSP. Also in this initial section is an IIR (infinite impulse response) recursive filter for removing jitter as the signal is passed to the oversampling DSP stage. ESS Technology claims this method allows the DAC to accept digital data with up to 50nS of random or 200nS of sinusoidal jitter and results in near-zero amounts of jitter in the digital signal which is now in the precision reference clock domain.
UltraDAC Block Diagram
The DSP oversampling rate converter achieves an exceptionally high clock rate (as much as 40MHz w/192kBS input) in a single step. This process is essentially bit-perfect and allows output dynamic range measures of 175dB to be achieved with correspondingly low total harmonic distortion figures.
The ESS HyperStream modulator uses a cascade of independently stabilized lower-order modulators to achieve a full scale modulation depth approaching 100%. Additional features of the modulator include a method to dramatically reduce noise artifacts with DC offset, and a complex noise-shaping filter that delivers exquisite audio resolution during transients.
The ESS9018 actually has 8 pairs of balanced DACs internally which are wired into four parallel balanced DACs each for the left and right channel. The output current of each channel’s DACs are sent to precision analog current to voltage converters, and then to the balanced and unbalanced line driver stages for output.
The UDAC has four separate high-quality power supply regulators delivering clean power to the various electronic sections of the DAC, and ensuring that all the excellent engineering of the ESS9018 is delivered to your awaiting ears.
