Cambridge Audio Azur 851W Power Amplifier - Black

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  • The 851W has class XD amplification at 200W into 8 Ohms in stereo mode or 500W RMS per amp in mono bridged mode, separate toroidal transformers for the power amp and input/other circuitry, and terrapin impedance buffering modules. All in all it's the best sounding amplifier we have ever made.



    Our best sounding amplifier ever, delivering a stunning 200 watts per channel. Works in stereo, mono or bridged mono mode for complete flexibility.  


    Our proprietary amplification system switches dynamically between Class A and AB systems. Class A amplification delivers the purest possible sound, using only one transistor to conduct, but can be energy inefficient. Class AB involves both transistors conducting simultaneously, but makes it impossible to maintain a balance of low crossover distortion and power efficiency.

    Our Class XD system operates in both Class A and Class AB mode, dynamically moving the crossover point depending on the audio output volume. This combines the near zero crossover distortion of pure Class A with improved efficiency of Class AB at higher volumes, without any compromises in performance for the best of both worlds.


    These proprietary modules replace the op-amps commonly found in similar amplifiers. At the critical low level gain stages, these offer far improved stereo separation and imaging – this is very rare at this price point.


    Extensive use of aluminium creates massive structural rigidity, while careful damping and control of acoustic resonance contribute to audiophile sound quality.


    Smart auto-standby mode detects incoming audio signals providing seamless integration with our preamplifiers.

    • High performance power amplifier
    • Designed to work in perfect synergy with the new Cambridge Audio 851E preamplifier
    • Proprietary Class XD amplification
    • Immense power capabilities
    • Can be used in stereo, bi-amped, or bridged mono configurations
    • Proprietary Terrapin impedance buffering modules
    • Two large toroidal transformers – one for the power amplifier itself and one for the inputs and other circuitry
    • Balanced and unbalanced analog audio inputs
    • Balance and unbalanced loop-out capability
    • Two pairs of speaker outputs per channel
    • Audio detect (Auto Power Up and Down) for power synchronization with the 851E preamplifier
    • CAP5 protection technology
    • Eco-friendly <0.5W Standby power consumption
    • Includes a  20 amp AC power cable
    • Power output – stereo/mono: 200 watts per channel into 8 Ohms; 350 watts per channel into 4 Ohms
    • Power output – bridged mono: 500 watts into 8 Ohms; 800 watts into 4 Ohms
    • THD (unweighted): < 0.001% 1 kHz; < 0.005% 20 Hz - 20 kHz
    • Frequency response: 5 Hz – 80 kHz
    • S/N ratio (ref 1W / 8 Ohm): >90dB (unweighted)
    • Sensitivity – stereo or mono: 1.5V rms unbalanced 1.5 + 1.5V rms balanced
    • Sensitivity – bridged mono: 0.775V rms unbalanced 0.775V + 0.775V rms balanced 
    • Input impedances: Balanced input 38 k Ohm; Unbalanced input 68 k Ohm
    • Damping factor: > 110 at 1 kHz
    • Max. power consumption: 2400 watts
    • Standby power consumption: <0.5W
    • Dimensions: 16.9" wide, 5.8" high, 14.4" deep
    • Weight: 42.2 lbs

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