The 840C incorporates a raft of new technologies and features. Key to its abilities is the ATFTM (Adaptive Time Filtering) upsampling process – developed in conjunction with Anagram Technologies of Switzerland.
This system intelligently interpolates 16 bit/44.1kHz CD (or other) data to 24bit/384kHz through the use of a 32 bit Analog Devices Black Fin DSP (Digital Signal Processor) for the very best sound quality. The ATF system applies sophisticated polynomial curve fitting interpolation and incorporates a time domain model which allows data buffering and reclocking almost completely eradicating digital jitter. Because the audio data rate is so high aliasing artefacts are moved way above audible frequencies allowing us to use a low order 2 pole linearphase Bessel filter on the output for constant group delay and minimal phase shift.
Two very high quality Analog Devices AD1955 24 bit DACs (Digital to Analog Converters) are used in dual differential mode. As each channel has its own DAC to process information, completely separate and symmetrical analog filter circuitry can be implemented. These allow both left and right channel circuitry to operate identically, ensuring the 840C delivers fantastic sound-staging and stereo imaging properties. All filtering from DACs to output is also fully differential using unique differential output amplifiers. This fully balanced configuration largely rejects the already very low noise and distortion products present in the DACs and filters and provides an unprecedented level of performance.A true balanced (XLR) output is fitted as well as a summed conventional unbalanced phono/RCA output. Automatic DC servo circuits null all DC offsets allowing no capacitors in the signal path at all. Two digital inputs are fitted allowing other digital sources to be brought into the 840C and upsampled,the 840C then working as a very high quality DAC.
A digital output is also fitted which can even output upsampled data at various rates and word widths, independent from the main audio output, which is always set at 24/384 for best sound quality. In addition to these audiophile features Control Bus Input/Output, IR Emitter Input and RS232 control are provided to make it easy to integrate this unit into Custom Installation systems if desired. A completely new 8-series casework has been designed which combines massive structural rigidity with careful damping and control of acoustic resonance. An Azur Navigator remote control is also provided, giving full remote control of your CD player and Azur amplifiers in an attractive and easy to use handset

Features

Adaptive Time Filtering (ATF) Asynchronous upsampling technology converting 16-bit 44.1 kHz CD data to 24-bit 384kHz
32-bit Analog Devices “Black Fin’ DSP
Dual differential DAC’s 2 x Analog Devices AD1955 24-bit DACs running at 384kHz
Fully differential output stage topology
Anti-aliasing filters based on linear phase Bessel filters for constant group delay and minimum phase shift
DC servo circuitry with no capacitors in the signal path
Digital inputs 2 co-axial, 2 optical allowing upsampling and playback of other sources
Digital outputs 1 co-axial, 1 optical allows recording of raw or up-sampled audio (192kHz maximum)
Audio outputs 1 balanced (XLR), 1 unbalanced
Other connections Control bus input/output, 1 IR emitter in, 1 RS232C, 1 IEC type mains inlet
Extruded aluminium side panels and solid aluminium front panel
Ultra rigid, acoustically dampened chassis
Full function aluminium face azur navigator remote
Available in silver/black

Performance

Frequency response 20Hz to 20kHz (+/-0.1dB)
THD
– @ 1Khz 0dBFs <0.0005%
– @ 1Khz – 10dBFs <0.0004%
– @ 20Khz 0dBFs <0.0007%
– (19/20kHz) 0dBFs <0.0002%
Linearity @ -90dBFs +/-0.5dB
Stopband rejection (>24kHz) > 120dB
S/N ratio, A weighted > 113dB
Total correlated jitter > 130pS
Crosstalk
– @ 1kHz > -130dB
– @ 20kHz > -114dB
Output impedance > 50 ohms
Digital input word widths supported 16 – 24 bit
Digital output word widths supported 16, 20, 24 bit
Digital input sampling frequencies supported: 32kHz, 44.1kHz, 48kHz, 88.2kHz, 96kHz, 176.4kHz, 192kHz
Digital output sampling frequencies supported:  32kHz – 192kHz pass through (including 44.1kHz for CD) 48kHz, 96kHz, 192kHz upsampled
Audio output upsampling Fixed 24 bit, 384kHz
Dimensions (hxwxd): 115 x 430 x 360mm (4.5 x 16.9 x 14.7″)
Weight 8.5kg (18.7lbs)