Azur 851C

Flagship Upsampling DAC, CD Player & Preamplifier

The 851C comprises a high-tech CD player, a digital to analogue converter and a preamp, it also has balanced XLR and unbalanced RCA analogue audio outputs, and selectable filters. So regardless of your input format, the 851C is designed to extract the purest sound quality possible.

Available Colours

Azur 851C

Flagship Upsampling DAC, CD Player & Preamplifier

The 851C comprises a high-tech CD player, a digital to analogue converter and a preamp, it also has balanced XLR and unbalanced RCA analogue audio outputs, and selectable filters. So regardless of your input format, the 851C is designed to extract the purest sound quality possible.

Available Colours

Three in one

With the 851C you get three high performance components in one impressive package:

  • CD playback supported by a number of digital inputs
  • Digital to analogue conversion using an advanced Analog Devices 24-bit DAC
  • Preamplification so all you need to add to create a system is a power amplifier such as the Azur 851W

Find out more in the video opposite.


The 851C can link up to almost anything! Connect it to your TV, PC, iPhone/iPad docks and streamers to maximise their sound quality. Or do it the other way around and play your music files via the USB audio input which allows for streaming of up to 24-bit/192kHz audio from computer.

ATF2 Upsampling

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

All incoming audio data, such as CD quality 16-bit/44.1kHz, is upsampled to 24-bit/384kHz using a high-end 32-bit Analog Devices DSP (Digital Signal Processor). "Polynomial 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.

Watch the video opposite to find out more.

Selectable Digital Filters

Our latest ATF2 DSP also features a selectable digital filter with three settings to suit listener preferences and your 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.

Structural Rigidity

Particular attention has also been paid to the 851Cs 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.

Our View
Sam E.
Product Manager
“While some audio designers spend every waking moment on the test bench, we like to take time to listen to our creations and hear how they benefit our favorite music. We take them home, listen to them with our friends and throughout the development process we make subtle changes- this results in a truly stunning performance.”


Hi-Fi News

"Frankly, the feature set of the 851C and 851A is the stuff of high-end audio dreams, but packaged in sensibly-priced components... As is so often the case with products from Cambridge Audio, what you're getting is cutting-edge technology for substantially less than high-end prices... This Azur combo took me to places I haven't been for a long time!"

United Kingdom - August 2012
European Imaging and Sound Association

"So while the 851C DAC/player brings a quiet composure to the party, the 851A is a wolf in sheep’s clothing, a muscular amp that grips the speakers and serves up tight, powerful and extended bass. In the 851C and 851A you’re getting cutting-edge technology for substantially less than high-end prices. Add the best speakers you can afford and this two-channel system will deliver a taste of hi-fi heaven."

United Kingdom - August 2012
What Hi-Fi? Sound and Vision

"There's fantastic precision in the way the 851C handles the leading and trailing edges of notes... An incredibly capable performer"

United Kingdom - October 2012
Hi-Fi Choice

"They now compete with the very best in class when it comes to sound and are pretty much in a league of their own when it comes to features... This refined and revealing pair delivers a dynamic, clean and engaging result."

United Kingdom - June 2012
AV Max

"The 851C truly lives up to all our expectations of being sweet, refined and simply musical. The amount of flexibility, in terms of usage, that imparts is very exciting and inviting. Be it as a CD player, a DAC or even the digital pre-amp. More importantly, the best part here is that irrespective of the mode/application that you decide to use it in, the sonic performance is absolutely consistent. Highly recommended!"

Read more - India - July 2014

"Cambridge Audio more than met my expectations... they’re both built incredibly well, they’re loaded with features, are customisable, versatile, easy to use and sound fabulous. The CD player is a knockout... The amp in particular is the best sounding unit of its type I’ve ever heard in this price range."

Read more - New Zealand - November 2012
Hi-Fi Choice

851C wins Hi-Fi Choice's CD Player of the Year! "Impeccably engineered and with sonics the match of most machines at twice the price, what's not to like? Smooth and svelte sounding yet commanding and incisive, only its rivals will regret the advent of this sparkling talented new CD player."

United Kingdom - November 2012
Audio Video Magazine

"Com excelente construção e design sóbrio, porém moderno, o Cambridge Audio 851C é um player honesto e um bom DAC cheio de recursos e entradas para satisfazer sonora e tecnicamente uma boa parte da legião crescente de usuários de media centers, music servers e computadores dedicados à reprodução musical de arquivos de alta definição da era da comercialização de músicas via internet."

Read more - Brazil - July 2014
HD Fever

"Musical, dynamic, pleasurable and sophisticated listening, enormous power, impeccable build quality, great design and ease of use - who could ask for more?"

Read more - France - October 2012
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  • 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 upsampling 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

Top Tips


Digital to analogue converterDual Analog Devices AD1955 24-bit DACs
Digital filterAnalog Devices Black Fin ADSP-BF532 32 bit DSP performing 2nd Generation ATF2 upsampling to 24-bit/384kHz. Linear Phase, Minimum phase or Steep modes.
Analogue filter2 Pole Fully Differential Linear Phase Bessel filter
Digital input 1S/PDIF 75 Ohms or TosLink optical
Digital input 2S/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)
Audio outputsBalanced XLR and unbalanced RCA analogue audio outputs
CompatibilityUSB 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 (unweighted) @ 1kHhz 0dBFs< 0.0004%
THD (unweighted) @ 1kHz -10dBFs< 0.0004%
THD (unweighted) @ 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 (ref 1w)> 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 output2.2Vrms (2.2Vrms each phase for the balanced output)
Max. power consumption40W
Idle consumption8W
Standby power consumption<0.5W
ColourBlack or silver
Dimensions (WxHxD)430 x 115 x 360mm (16.9 x 4.5 x 14.7”)
Weight10.0Kg (22lbs)

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