User manual NAIM1 DAC BROCHURE

[. . . ] Simultaneously with its introduction, the CDX2 and CD5 XS CD players have gained S/PDIF outputs and can now benefit significantly from use with the DAC. With the addition of a DAC, existing preamplifiers can be incorporated into digital audio systems. The Naim DAC can be controlled by a Naim preamplifier remote control, seamlessly integrating analogue and digital inputs across the two units. [. . . ] The analogue lowpass filter removes high frequency artifacts, and buffers the signal for a preamplifier. Designing an external digital to analogue converter capable of offering the exceptional musical performance obligatory for a Naim product brings numerous technical challenges. In particular, the S/PDIF interface protocol for digital interconnection has significant jitter and noise problems. Original solutions to these problems had to be conceived and developed. The Naim DAC has more in common with Naim CD players than with conventional external digital to analogue converters. It overcomes the jitter issues of S/PDIF by reading the data into a "rotating" data RAM buffer independently of its timing signal and reading it out again clocked by one of ten extremely low noise, fixed frequency crystal sine-wave oscillators. In terms of system topology, the DAC's rotating memory is analogous to a rotating CD feeding raw data to be reclocked. The rate at which the memory fills and empties is controlled by the DAC automatically selecting the oscillator that matches the average incoming clock frequency. The data entering the downstream digital filtering and DAC chips is then completely isolated from the incoming S/PDIF jitter. Along with being a source of jitter, S/PDIF is a potential source of RF noise. The Naim DAC suppresses S/PDIF noise through electrical isolation of its DSP front end from the digital to analogue converter and analogue circuits. Each element is also run from separate power supplies The Naim DAC's digital filtering is handled by a powerful SHARC DSP chip running unique Naim authored code to create an ultra high precision 40bit floating point filter. The filter over-samples by 16 times on 44. 1kHz data and provides stop-band attenuation of 180dB on all data. Following the digital filter are the two mono Burr-Brown digital to analogue converter chips, as used in the CD555 CD player. Finally the Naim DAC features a very high performance, low noise, and low distortion fully discrete analogue output stage. Ground breaking technology and digital audio engineering however are purely academic. Listening to the Naim DAC is something else entirely. Startling in its clarity, arresting in its detail, beguiling in its warmth and inspiring in its rhythm, the Naim DAC seduces from the first note. ANALOGUE FiLTERS Two cascaded third order Sallen-key active filters giving 36dB/Octave roll-off. [. . . ] A true multi-bit digital to analogue converter chip as used in the CD555. BLACkFiN DSP Handles USB, controls the DAC and conditions the incoming USB data. DATA RAM Buffers the incoming S/PDIF data stream ready for re-clocking by RE-CLOCkiNG GATE Re-clocks the data immediately before it enters the DAC chips to remove any influence from the isolation circuits. the appropriate crystal oscillator. APPLE AUTHENTiCATiON CHiP Enables the DAC to access digital data from iPod and iPhone models. The Naim DAC is the world's first Apple-Authenticated highend digital to analogue converter. CRYSTAL SiNE-WAVE OSCiLLATORS Crystal oscillators have lower signal correlated noise and phase noise than voltage controlled clocks. [. . . ]