The Naim DAC marks a technical milestone comparable to our first CD player, the CDS. The CDS demonstrated that CD replay and lifelike music reproduction were not mutually exclusive. Now, the Naim DAC demonstrates that the jitter and noise that bedevil traditional external digital to analogue conversion can be overcome and a new route to the real enjoyment of music opened. The Naim DAC provides eight S/PDIF inputs, two USB inputs, and is capable of handling audio data sampled at up to 768kHz and with up to 24bit resolution. It not only brings all the digital inputs together into the analogue domain, but does so with a level of performance that can compete with the finest from any Naim CD player to provide unrivalled musical fulfilment.
Listening to the Naim DAC is a revelation. Music, whether its source be an iPod, a CD or a high resolution data file, is presented afresh, with more definition, more insight, more warmth, and simply more of those hard to-define clues of rhythm, melody and emotion that distinguish the real thing from pale imitation. The Naim DAC is an advance that brings real music in the home closer to reality than ever before.
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 40-bit 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.
For more technical detail please read the white paper available for the DAC