Three chassis form the foundations of the C1 Mono. Leveraging the technologies from the original C1, the C1 Mono separates the digital processing section from the two analog sections.
Dedicated chassis and internal power supplies for each section allow this product to reach the next level of performance in music reproduction. Add another three X1 External Power Supply units and the C1 Mono becomes CH Precision 1-Series’ ultimate digital to analog controller.
The C1 Mono inputs are modular like into the original C1, sharing a common platform. Furthermore, stereo C1 Digital to Analog Controller units can be upgraded to C1 Mono.
Up to three input boards allows the unit to include many input types. One digital input HD board is provided in base configuration, while two slots are kept free and can be fitted from factory or after product installation with the following board types:
- digital input HD board (1x CH Link HD, 1x AES/EBU, 1x S/PDIF and 1x Toslink)
- analog input board (1x XLR balanced and 1x RCA single-ended)
- USB input (1x USB B-type)
The CH-Link HD interface allows for synchronized transfer of High Definition audio content and control over a single connection and is the optimal link between the C1 mono and the matching D1 SACD/CD drive. Audio data on CH-Link HD is cyphered when protected content is transmitted.
The ethernet audio input board option replaces the ethernet control board, turning the C1 mono into a UPnP, Tidal, Qobuz and Web radio compatible network player. It should be noted that this input can be added even if the three available input slots are fitted.
For each channel a fully programmable 2.4GFLOPS DSP engine is used for the following processes:
- proprietary CH-PEtER processing for data upsampling at 705.6kHz/768kHz
- DSD to PCM direct conversion at 705.6kHz
- resolution enhancement for data streams of less than 24 bits resolution
- D/A converters data scrambling
This DSP engine also linearizes each of the four R-2R converters - its absolute output level as well as DC offset is taken into account - thanks to a calibration process which is done at factory but can also be performed by the user afterwards to maintain optimal operation over time.
Timing & clocking
Extreme care has been given to the timing of the audio conversion. The clocking section of the C1 mono is based on two ultra low jitter digitally controlled VCXOs to support synchronously every available audio sampling rates.
When equipped with the optional synchronization board, the C1 mono can be used with external clock generators like the CH Precision T1, or it can transmit the D1 SACD/CD drive a synchronization clock in order to slave it.
The digital to analog converter boards are full dual mono with one board per channel. A dedicated set of regulated power supplies has been built for each channel in order to keep the channel separation at its maximum. Each channel is using four R-2R converter in a balanced design to create directly from the D/A conversion process an analog balanced signal.
An integrated hybrid volume control is embedded into the C1 mono, which can be turned off in case an external analog preamplifier is used. It has been done with a mix of analog and digital steps to ensure the best possible resolution at all listening levels. Coarse steps are done with relay-driven resistor-based dividers, while the fine steps are done into the DSP engine in floating point.
All analog stages of the audio signal inside the C1 mono are built only with discrete components, no operational amplifier have been used into these sections. This deliberate choice warranties the shortest path for the audio signal and allows the use of custom-designed building blocks. All analog stages have the following features:
- no use of global negative feedback
- operating mode in pure class A
- fully symmetrical design
No capacitors have been used in the signal path to ensure the maximum transparency.