SHARC DSP
Operates on the digital data to filter the out-of-band artifacts.
40bit, 16 times over-sampling topology.
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
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 high-
end digital to analogue converter.
ANALOGUE FiLTERS
Two cascaded third order Sallen-key active
filters giving 36dB/Octave roll-off. Each stage
incorporates Naim zero-feedback
complimentary buffers.
i TO V CONVERTERS
Convert the current output of the
digital to analogue converters to
a voltage waveform ready
for analogue filtering.
DSP TO ANALOGUE ELECTRiCAL iSOLATiON
Ensures that the high frequency noise of digital
electronics cannot leak into the analogue output stages.
Technology under the hood
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 re-
clocked. 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.
The nature of music delivery is changing fast. CD has
been joined by downloads, portable music players
are part of the landscape, computers are routinely
connected to hi-fi systems, and USB memory sticks are
used to store high resolution music files. So the Naim
DAC, our first stand-alone digital to analogue converter,
arrives at an exciting time in the narrative of high quality
music in the home. And listening to the DAC builds the
excitement yet more.
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 converters 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 fulfillment
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.
Naim digital to analogue - for the converted
Upgrade Path
Upgrades are a fundamental element of the Naim philosophy. As well as providing a significant performance
upgrade for the CDX2 and CD5 XS CD players, and HDX hard disk player, the Naim DAC can itself be upgraded
by the addition of an XPS or 555 PS external power supply.
The essential ingredients
Each element of the Naim DAC has a vital role to play
in its musical virtuosity, but it is not just the specifics
of each that is important, it is their organisation also.
The influence of signal path, the microphony of
circuit boards, the impact of track layout, the noise
contribution of components, the noise sensitivity of
others - each one is vital, and each one influences
every other.
The DAC signal path is fundamentally simple. The
SHARC DSP, operating as a filter, receives the data, then
over-samples and low-pass filters the data and feeds
this to its peripheral memory. Also operating as a buffer;
the memory outputs data clocked by the oscillator. The
DAC chips turn digital into analogue current, and the I to
V converters turn current into voltage. The analogue low-
pass filter removes high frequency artifacts, and buffers
the signal for a preamplifier.
LOW NOiSE POWER SUPPLY
Multi-regulated and smoothed
power supply with separate
outputs for each element.
CHASSIS
The 3mm aluminium
chassis and machined-
from-solid fascia
provide the fundamental
structural rigidity
necessary for low
microphony.
DAC CHIPS
Burr Brown PCM1704k. A true multi-bit digital to
analogue converter chip as used in the CD555.
RE-CLOCkiNG GATE
Re-clocks the data immediately before it enters the DAC
chips to remove any influence from the isolation circuits.
CRYSTAL SiNE-WAVE OSCiLLATORS
Crystal oscillators have lower signal correlated noise
and phase noise than voltage controlled clocks. The
DAC employs ten
separately tuned
oscillators.
TRANSFORMER
Low stray-field,
multiple secondary
windings.
PRiNTED CiRCUiT BOARDS
Six layer glass fiber PCBs
optimised for low microphony
and high speed data transfer.