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Cambridge Audio 851C Upsampling DAC, CD Player and Preamplifier


AU$1999
Model: 851C


Product Overview:

The heart of your digital music system

Our new 851C is a staggeringly complex creation but one with a simple mission: to make your digitally stored music sound sublime. It's a high-end CD player, a state-of-the-art DAC and digital preamp in one highly accomplished package. The 851C has been designed to operate at the very heart of your digital music system, offering incredible functionality and performance. As a high-end solution to the demands of today's multi-format music lover, the 851C is truly capable of enhancing any digital audio that passes through its sophisticated electronics.

Central to the 851C's exceptional performance is a mouth watering collection of advanced technologies, such as our high-specification digital-to-analogue convertors from respected digital processing experts Analog Devices. Together with its on-board ATF2 upsampling technology, the 851C has the ability to improve sound quality regardless of the input format. From MP3 to high res downloads, this player will showcase your music in its best possible light.

With a plethora of connectivity options, you can link up a world of digital source components to the 851C, including: TVs, streamers, digital iPhone/iPad docks and computers of all kinds to maximise their sound quality. The 851C is also capable of accepting the very highest quality music files currently available, via USB: 24-bit/96kHz (and 192kHz) for genuine studio master tape quality. So you really can get closer to the music than ever before.

For the serious audio enthusiast, the 851C also benefits from a number of ,'audiophile' features. Everyone's ears are different and you can select from three filter options which each offer a slightly different presentation.

It's this combination of our own in-house technology, multi-function flexibility and high-end ,'audiophile' components that make the 851C Cambridge Audio's most advanced digital player to date. Its ability to transform the quality of your favourite music, regardless of format, means the 851C is destined to become the heart of your digital music system.

Particular attention has also been paid to the 851C's casework, which combines massive structural rigidity, careful damping and control of acoustic resonance. Both inside and out, the 851C and matching 851A have all the hallmarks of high-end thoroughbreds.

ATF2 Upsampling in more detail…

The 851C makes all your digital audio sound amazing – drawing detail seemingly out of thin air. How?

Our unique ATF2 (Adaptive Time Filtering) upsampling technology, developed in conjunction with Anagram Technologies, Switzerland.

logo-upsamplingAll incoming audio data, such as CD at 16-bit 44.1kHz CD, is upsampled to 24-bit 192kHz using a high-end 32-bit Analog Devices DSP (Digital Signal Processor). "Polymomial Curve Fitting Interpolation" provides a much more accurate upsampled audio soundwave than traditional upsampling processes. And a unique timing system buffers audio data to almost eradicate digital jitter. Vital – as jitter, common in digital audio devices, loses vital detail, often leaving digital audio sounding flat and lifeless.

Our latest ATF2 DSP also features a selectable digital filter with three settings to suit listener preferences and their particular system set-up: 

• The Steep roll-off filter exhibits strong attenuation of aliasing images outside the pass band (i.e. above 22.05kHz) at the expense of a little pre and post-ringing in the time domain. 

• The Linear phase filter uniquely features ‘constant group delay’ which delays all audio signals at all frequencies by the same amount meaning all audio is fully time-coherent at the output.

• Minimum phase meanwhile does not feature constant group delay but rather the co-efficients have been optimised without feed-forward so that the impulse response exhibits no pre-ringing in the time domain.




  • Digital to Analogue Converter featuring S/PDIF and Toslink digital inputs, AES/EBU balanced digital input and USB audio inputs (all 24 bit compatible)
  • CD playback
  • Optional digital volume and channel balance control
  • Balanced XLR and unbalanced RCA analogue audio outputs
  • USB Audio input allowing streaming of up to 24-bit/192kHz audio from computer
  • ATF2™ audio up-sampling to 24-bit/384kHz
  • Twin Analog Devices AD1955 24 bit DACs delivering superior sound-staging and stereo imaging
  • Selectable digital filters – linear phase, minimum phase, steep
  • Audiophile grade toroidal transformer delivering ultra-low low noise and distortion
  • Full metal casework design with thick brushed aluminium front panel and dual layer damped feet, giving enhanced resonance control
  • RS232 controllable
  • Eco-friendly <0.5W Standby power consumption
  • Azur Navigator remote control with Cambridge Audio amplifier and iPod dock control
  • Available in black and silver finishes
  • Digital to Analogue Converter: Dual Analog Devices AD1955 24 bit DACs
  • Digital filter:
    Analog Devices Black Fin ADSP-BF532 32 bit DSP performing 2nd Generation ATF2 up-sampling to 24-bit/384kHz.
    Linear Phase, Minimum phase or Steep modes.
  • Analogue filter: 2 Pole Fully Differential Linear Phase Bessel filter
  • Digital Input 1: S/PDIF 75 ohms or Toslink optical
  • Digital Input 2: S/PDIF 75 ohms or Toslink optical
  • AES/EBU Input: XLR balanced 110 ohms per phase
  • USB Audio Input: USB Type B conforming to Audio profile 1.0 or USB Audio profile 2.0 (user 1.0 or USB Audio profile 2.0 (user selectable)
  • Analogue audio outputs: Balanced XLR and unbalanced RCA analogue audio outputs
  • Compatibility:
    USB 1.0 16-24 bit, 32-96kHz
    USB 2.0 16-24 bit, 32-192kHz
    Toslink 16-24 bit, 32-96kHz
    S/PDIF and AES/EBU 16-24 bits 32-192kHz
    CD playback is intrinsically limited to 16-bits 44.1kHz
  • THD @ 1Khz 0dBFs: < 0.0004%
  • THD @ 1Khz -10dBFs: < 0.0004%
  • THD @ 20Khz 0dBFs: < 0.0007%
  • IMD (19/20kHz) 0dBFs: < 0.0002%
  • Linearity @ -90dBFs: +/- 0.2dB
  • Linearity @ -120dBF: +/- 0.4dB
  • Stop-band rejection (>24kHz): > 120dB
  • S/N ratio, A weighted: > 113dB
  • Total correlated jitter: < 60pS for all digital inputs, CD playback and USB 2.0; < 180pS for USB 1.0
  • Crosstalk @1kHz: < -130dB
  • Crosstalk @20kHz: < -114dB
  • Output impedance: < 50 ohms
  • 0dB Fs Output: 2.2Vrms (2.2Vrms each phase for the balanced output)
  • Max. power consumption: 40W
  • Idle consumption: 8W
  • Standby power consumption: <0.5W
  • Dimensions (W x H x D): 430 x 115 x 360mm (16.9 x 4.5 x 14.7”)
  • Weight: 10.0Kg (22lbs)