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2020 Advance D/A Converter
Boulder’s analog expertise and digital Upandoversampling
The 2020 D/A Converter is an incredible
combination of digital and analog engineering
assembled together in a luxurious chassis. The multibit approach was chosen as it is the de facto standard
for sonic clarity being free from the problems found
in sigma delta schemes.
The main objective of oversampling and
interpolating digital audio data is to take advantage
of the reliability and sonic accuracy
afforded by digital filtering techniques,
thus reducing the audibly deleterious
effects of false imaging which occur in the
D/A conversion process.
A digital filter in combination with
oversampling provides a high-resolution
prediction of the digital audio data between
recorded samples in time and simultaneously pushes
the unwanted false image out to a higher frequency
where inaudible analog filters may be used to
effectively eliminate it.
TM
The best designed digital filters are the Finite
Impulse Response (FIR) type, of which the eigenfilter
approach has been shown to create the least aliased
images back into the audible range.
While ordinary cascaded digital filters use 24-bit
interpolation, resulting in a passband rejection of
only 106 dB, Boulder has designed a much higher
performance filter using 32-bit interpolation
thereby achieving 144 dB (a 24 bit level)
rejection in the audio band. To achieve this
interpolation and the necessary 16 times
oversampling of CDs, an expensive one
gigaflop DSP engine was required.
UpandoversamplingTM combines both
the ”up” and ”over” sampling steps into
one process thus assuring sonic clarity
under any conditions.
The Boulder 2020 is the only DAC capable of
bringing such a high level of digital design expertise
to music reproduction in your home.
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The Boulder 2020 DAC receives the
digital signal via one of six inputs. It
is then completely de-jittered through
the use of a phase lock loop circuit,
essentially performing a reclocking of
data.
After processing in the 32 bit DSP,
the 24 bit signal is transferred at data
rates over 700kHz from the main
chassis to the audio boxes. The five Burr
Brown converters (per channel) yield
the purest, quietest signal possible.
From here the Boulder analog
expertise takes over. All gain stages are
the Boulder 993, the first in a special
current to voltage converter circuit. It is deliberately
bandwidth limited as the first step in removing
digital aliases.
Next a triple 993, six pole Bessel filter removes
the remaining artifacts, but leaves the audio band
untouched. A fifth 993 creates the balanced output.
During creation of the Boulder 2020, it was obvious
that there was a lack of attention to the analog in
other designs. By including the required quantity of
993 stages, sonic clarity was taken to a level beyond
any other design.
A special feature is the ability to change the timing
between channels. This ”time advance” feature is
useful in effectively moving the listening position to
one side of the room, thus accommodating a favorite
listening position. A remote control is provided to
allow adjustment of this and other 2020 features.
The three section chassis design (left audio,
right audio, and digital) removes any interference
between the analog and digital sections. An elegant
combination of stainless steel, aluminum and powder
coating complements any decor.
Two digital outputs are provided. One follows
the main source, while the second can be separately
selected for simultaneously feeding a recorder.
A separate 2000 Power Supply features three
individually magnetically shielded toroidal
transformers. Three independent regulated supplies
power each of the audio channels and the DSP/
digital/display circuitry.
The attention to detail in both the digital and
analog sections will bring new life to your entire
music library.
SPE CIFICATIO NS
DIGITAL INPUTS 4 AES/EBU, Conver ts to SPDIF,
1 Toslink, 1 ST Glass
DIGITAL OUTPUTS 2 AES/EBU, Converts to SPDIF
ANALOG OUTPUTS
NOMINAL OUTPUT
ANALOG HEADROOM
SIGNAL TO NOISE 118 dB A weighted, 115 dB flat
FREQ RESPONSE +0, - 0.05 dB, 20 Hz to 20 kHz
THD+N, 0dBFS 0.002 % , 20 Hz to 20 kHz
CONVERTER 18.0 wide, 6.875 high, 16.25 deep (in.)
POWER SUPPLY 18.0 wide, 4.25 high, 16.25 deep
WEIGHT 90, Shipping: 115 Pounds
POWER 120 VAC, 50 - 60 Hz, 180 W
32 35 P rai rie Ave. • Boulder, CO 8 030 1
30 3-4 49- 822 0 • www.boulderam p.com
2 Balanced Main
4.0 Vrms
10 dB
Bo uld er A mpl ifi ers , Inc.
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