(4) Power supply section
(5) Main power transformer
(6) Standby power transformer (ensures green mode Standby)
(7) Power supply regulation board
(8) AMOLED display (on front panel)
(9) Audio in, clock in/out, USB (firmware update) and RJ-45 (control/network) connectors (from slot-in boards). Analog ground to Earth jumper
(10) Slot-in boards (SYNC_IO, CONTROL/NETWORK, DIGITAL_IN/USB_IN/ ANALOG_IN)
(11) Main processing and control board
(12) Left channel DAC board
(13) Right channel DAC board
(14) Concentric push control knob
1.1 Digital to analog conversion
The C1 D/A controller is built around a synchronous CH-HiD processing engine feeding two first grade factory-calibrated monaural
D/A conversion boards. The conversion stage is a linearized R2R topology, followed by a fully discrete output stage. The whole
purpose of this design is not only to reconstruct correct level information but also perfect timing, since it is the key element for
recreating nature-like immersion into a musical performance.
1.1.1 Clock management
The first requirement to achieve perfect timing is that audio data are fed into the DAC chips synchronously to a jitter-free clock.
This is why two high-precision low-drift audio crystal clock oscillator (22.5792 MHz for 44.1 kHz multiples and 24.576 MHz for 48
kHz multiples) are located only a few cm from the DAC chips. The clocking section has its owns dedicated power supply fully
decoupled (complete galvanic isolation) from all noisy digital signals. This critical Masterclock signal is carried to the DAC chips in
LVDS (low-voltage differential signaling) form to avoid any cross-talk pollution.
In order to be synchronous to the incoming audio signal, these crystal oscillators can be fine tuned using a voltage controlled
feedback (VCXO), computed by a proprietary algorithm. Performances of this “digital phase-locked loop” (digital PLL) is jitter
rejection below 0.1 Hz, while frequency tracking is achieved through sub 0.1 PPM correction steps. Phase alignment is also
guaranteed with a +/-2.5 us accuracy. When combined with matching CH D1 SACD/CD drive and optional synchronization boards
(or a computer source), the C1 can even be configured as the clock master, having the source (either CH D1 or computer) clock-
enslaved. In such configuration, the jitter is completely removed from the system.
1.1.2 HiD processing engine
After years of development in the high-end audio industry we came to the conclusion that the digital samples contained in the
original audio stream should remain untouched, only computing missing information between them to remove most of the burden
(and phase non-linearity) off the analog filtering stage. Compared to widely-used asynchronous sample rate conversion (ASRC),
synchronous up-sampling removes all harshness often found in digital players.
Rev 1.9 C1 User Manual 9
To Next Page
Loading...