1 Preamplifier
What makes an edge-of-the-art high-end preamplifier? Some say the
quality of its component parts.For them the D1 exhibits an impressive
résumé—best-quality Crystal® analog attenuators, high-value ADC
reference voltage decoupling capacitors, audio-grade Nichicon®
MUSE® Series UK signal-coupling capacitors, low-ESR electrolytic
OS-CON SVP capacitors, and the list goes on. For others, it’s in the
details—the number of design features compared with other highend preamplifiers on the market. One simply has to glance at the D1’s
Design Overview (pages 5 and 6) to see why it is one of the most
comprehensive, feature-laden high-end preamplifiers on the market.
Finally,some use price to measure a preamplifier’s worth—it stands
to reason the more expensive the preamplifier, the better the performance. Or does it? The D1’s sonic presentat ion rivals that of the most
expensive preamplifiers. Highs are refined,open and silky smooth.
Mids are rich, full and exceptionally revealing. Bass presentation
is articulate, with extraordinary power,depth and pace while still
capturing the delicate edge of each leading bass note.
3
Better By Design (continued)
Nine High-End Components in One:
•
Preamplifier
•
24-bit/192-kHz Precision Upsampler
•
Analog-to-Digital Converter (ADC)
•
Digital-to-Analog Converter (DAC)
•
Surround-Sound Processor (SSP)
•
HDTV Video Switcher
•
Mult iro om/Wh ole-House Entertainment Control Center
•
Built-in FM/AM Tuner
•
Headphone Preamplifier
3 Analog-to-Digital Converter (ADC)
Our use of the highest-quality ADCs essentially eliminates ultrasonic
noise and distortion in the 20 kHz to 80 kHz frequency band. Dual
independent six-layer converter boards use separate analog and digital planes as well as separate power- and groundplanes for remarkably low noise. The AKM® AK5495A ADCs are capable of up to 24bit x 192-kHz resolution.
Analog input level is controlled through a balanced configuration of
six highest-quality stereo Crystal® CS3310 analog attenuators
arranged in differential mode—one for each channel of the 6-channel
input. This arrangement promotes greater dynamic range and contributes to an impressive reduction in distortion.
High-value (1,000 µF) ADC reference voltage decoupling capacitors
provide the lowest possible THD+N below 1 kHz.
Low-ESR electrolytic OS-CON SVP capacitors are used to decouple the
input stage bias reference voltage ensuring lower noise and distortion.
Aud io-grade Nichicon MUSE Series UK signal-coupling capacitors
with low-voltage coefficient ensure minimal distortion and low
microphonics reducing the ADC’s sensitivity to vibration.
All Digital-to-Analog Conversion (DAC) uses a reconstruction filter
as the final step in the conversion process.Without this filter, recreating t he original signal would not be possible. The side-effect of this
filtering,however, is a harshness in the upper frequencies—a result of
audible errors in phase- and frequency-response. The best high-end
DAC desig ns go to great lengths to minimize this distortion, with
very good results. The D1,however, does even more …
UPSAMPLING: Increases the sampling rate of the incoming digital
signal. This allows the reconstruction filter to operate at a higher
frequency, making it less intrusive in the audible bandwidth. While
outboard Upsamplers can be purchased as an add-on component,their
output is restricted to a maximum of 96 kHz due to the bandwidth
limitation of S/PDIF (RCA/Toslink) and AES/EBU digital connections.
When outboard Upsamplers are used with SSPs or separate DACs
capable of 192 kHz they will, in reality, never operate at better
than 96 kHz. In addition, they only operate on 2-channel PCM, not
on decoded Dolby® Digital or DTS® program material.
The D1 includes its own built-in state-of-the-art Upsampler incorporating Analog Devices’ AD 1896 and converts the sample rate of all
incoming digital signals to 192 kHz.Since this is done completely
inside the D1 there are no digital connections to limit the upsampling
frequency. Our D/A converters then operate at their full 192 kHz
capability. And unique to the D1,our Upsampler also operates on all
decoded Dolby® Digital and DTS® program material.
OVERSAMPLING: Along with upsampling, the D1’s DACs also incorporate 128X oversampling to increase the sample rate to 24.576 MHz,
thereby ensuring the best phase- and frequency-response possible.
This combination of upsampling and oversampling allows the D1 to
use much gentler 3rd-order Bessel reconstruction filters.Measurable
results are profoundly superior, reflecting exceptionally flat frequency
response and THD+N in the upper frequencies up to twenty times
lower than some of the best high-end outboard DACs.
Sonic performance is astounding—smoother high-frequency
response,superior detail,better image focus—in essence, a far more
transparent window on the original performance. While this is enormously beneficial for music it is even
more beneficial for home theater. Since
the D1’s Upsampler operates on all
formats and all channels,the result is a
much higher level of transparency for
both multichannel music and movies.
2 24-Bit/192-kHz Precision Upsampler