C1 Reference Digital to Analog Controller

  1. General
  2. Features
  3. Options
  4. Specifications

Designed for the true music lover, the C1's apparent simplicity hides highly sophisticated technological solutions with the single goal of recreating the full musical experience. This emotion can only be achieved when both level and time information are properly reconstructed from the digital data. And this is what the C1 is all about...

The C1 is based on a fully modular, future-proof architecture. Up to three inputs boards include standard digital inputs complemented by the proprietary CH-Link interface. Optional streaming audio inputs as well as line-level analog inputs enable the use of the C1 as a full featured preamplifier thanks to its integrated volume control.

A reference grade linear power supply (with <1W power consumption in standby mode), sophisticated mechanical chassis design and full USB based firmware update also contribute the C1's uniqueness, for now and for any future format!


Up to three input boards allows the unit to include many input types. One digital input 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 board (1x AES/EBU, 1x S/PDIF, 1x Toslink and 1x CH Link)
  • analog input board (1x XLR balanced and 1x RCA single-ended)
  • USB input (1x USB B-type)

The CH-Link interface allows for synchronized transfer of High Definition audio content and control over a single connection and is the optimal link between the C1 and the matching D1 SACD/CD drive. Audio data on CH-Link is cyphered when protected content is transmitted.

The ethernet streaming board option replaces the ethernet control board in order to add the C1 a uPnP/DLNA compatibe input. 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-HiD processing for data over-sampling at 705.6kHz/768kHz
  • DSD to PCM direct conversion at 705.6kHz with selectable low-pass filters
  • 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 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 can be used with external clock generators or it can transmit the D1 SACD/CD drive a synchronization clock in order to slave it.

D/A conversion

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.

Volume control

An integrated volume control is embedded into the C1, 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.

Analog stages

All analog stages inside the C1 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-made building blocks. All analog stages have the following features:

  • no use of global negative feedback
  • operating mode in pure class A
  • fully symetrical design

No capacitors have been used in the signal path to ensure the maximum transparency.

Options boards



Ethernet control board

General control board. Provides USB based firmware update and external ethernet control.

Factory built-in



Stereo digital input board

Four digital inputs - CH Link, AES/EBU, S/PDIF and Toslink - are provided on a single board.
Allows up to twelve digital inputs into a single C1.

Factory built-in (1x)



Clock synchronization board

Allows unit synchronization as clock slave. Audio frequencies as well as atomic clock frequencies are supported. A clock master mode is also provided to synchronize external units.



USB audio input board

Enables bit-exact, low jitter playback of high resolution audio files from a computer.



Ethernet audio streaming board

Enables bit-exact, low jitter playback of high resolution files over an ethernet network.
A uPnP control application is required, as well as a file server.



Analog input board

Stereo analog line level input board. One set of balanced and unbalanced inputs is provided.

External power supply



X1 external power supply

Improves the overall C1 performances by adding an external power supply unit.

Same unit dimensions as the C1

Digital inputs
CH Link
High Definition Link

PCM 16 to 32 bit / up to 768kHz
DSD 1 bit / 2.8224MHz & 5.6448MHz, cyphered


XLR connector, up to 5Vpp, 110Ω

PCM 16 to 24 bit / up to 192kHz
DSD 1 bit / 2.8224MHz (DSD64), DoP encapsulated


RCA connector, up to 1Vpp, 75Ω

PCM 16 to 24 bit / up to 192kHz
DSD 1 bit / 2.8224MHz (DSD64), DoP encapsulated


Optical connector

PCM 16 to 24 bit / up to 192kHz
DSD 1 bit / 2.8224MHz (DSD64), DoP encapsulated

Streaming inputs
USB input
asynchronous mode

PCM 16 to 32 bit (fixed point) / up to 384kHz
DSD 1 bit / 2.8224MHz (DSD64) & 5.6448MHz (DSD128), DoP mode only

Ethernet input
asynchronous mode

PCM 16 to 32 bit (fixed point) / up to 192kHz (384kHz for uncompressed formats)
DSD 1 bit / 2.8224MHz (DSD64), 5.6448MHz (DSD128) & 11.2896MHz (DSD256), native DSD and DoP

WAV, AIFF, FLAC, ALAC, AAC, MP3 format supported in PCM
DSF, DFF format supported in DSD

Analog inputs
Inputs type Balanced, 6V RMS maximum input level
Single-Ended, 6V RMS maximum input level
Input stage Discrete fully differential input stage
A/D conversion DSD 1 bit / 5.6448MHz (DSD128) direct conversion
D/A Conversion
Conversion type Linearized R-2R, 4x PCM1704 per channel, 24 bit / 705.6kHz & 768kHz
DSP processing CH-HiD upsampler, synchronous, DSD to PCM conversion
and resolution enhancer
Analog outputs
Outputs type

Balanced (XLR), one pair
Single-Ended (RCA & BNC), one pair each

Output stage

Discrete I/V stage with ultra-high bandwidth
Active discrete filtering stage
High-current discrete output stage

All analog stages have a zero global negative feedback

Output level 5.4V RMS in balanced mode
2.7V RMS in single-ended mode
Signal to Noise Ratio Better than 120dB
Total Harmonic Distortion + Noise Less than 0.001%
Clock input
BNC, 0.5Vpp to 5Vpp

75Ω or Hi-Z

44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz
22.5792MHz, 24.576MHz
100kHz, 10MHz

Clock output
2x BNC, 2Vpp, 75Ω

input sampling frequency or input clock if externally synchronized

Display 480x272 pixels, 24bits color, AMOLED
Mains operation Selectable 100V, 115, 230V AC, 47-63Hz
Fuses value and location Standby fuse (black holder): 250mA T (230V AC), 500mA T (100V AC, 115V AC)
Main fuse (white holder): 1.6A T (230V AC), 3.15A T (100V AC, 115V AC)
Power supply consumption <1W (standby), 60W average in operation
Dimensions/Weight 440 x 440 x 133mm (W x D x H), 24kg
Remote control IR Remote control provided, RC5 codes
Ethernet based system control via the Android CH Control App
Adobe-PDF-Document-icon Product flyer
Adobe-PDF-Document-icon User manual

C1 firmware version 4.1 (release date 2017-12-28)

Adobe-PDF-Document-icon USB audio input board firmware update procedure
Compressed-File-Zip-icon New USB audio input board firmware (v6.6.2)
Compressed-File-Zip-icon New USB Class 2.0 Windows driver (for firmware v6.6.2)
Adobe-PDF-Document-icon Legacy USB Audio Class 2.0 driver installation procedure under Windows 10
Compressed-File-Zip-icon Legacy USB Audio Class 2.0 Windows driver (for USB audio input boards produced before April 2016)

CH Control application 2.2.1 (release date 2018-01-03)