Cambridge Audio Azur 851W Stereo Amplifier

Rather than use a Class A design, which is sonically brilliant but generates vast amounts of heat, or a Class AB design, which is efficient but sonically limited, we developed our own Class XD amplifier design which the 851W takes advantage of. This has the sonic purity of Class A and the efficiency of Class AB for the best of both worlds.


The 851W can be used in stereo, bi-amped or bridged mono configurations. In bridged mono mode into 8 Ohms the 851W is a 500W monoblock amplifier. Into 4 Ohms, this figure increases to an incredible 800W. It can be paired with our 851E pre-amp, any of our digital pre-amps such as the 851N or CXN, or any other analogue pre-amps, and thanks to our Terrapin buffering module it will always sound perfectly matched. 




  • POWER OUTPUT – STEREO/MONO: 200W per channel into 8 Ohms 350W per channel into 4 Ohms
  • POWER OUTPUT – BRIDGED MONO: 500W 8 Ohms 800W 4 Ohms
  • THD (UNWEIGHTED): < 0.001% 1 kHz < 0.005% 20 Hz - 20 kHz
  • S/N RATIO (REF 1W / 8 OHN): >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 kOhm Unbalanced input 68 kOhm
  • POWER AMP DAMPING FACTOR: > 110 at 1 kHz
  • COLOUR: Black or silver
  • DIMENSIONS (HXWXD): 148 x 430 x 365mm (5.8 x 16.9 x 14.4”)
  • WEIGHT: 19.1kg (42.2lbs)
  • IN THE BOX: Azur 851W Power Amplifier, Power Cable, 3 x AAA Batteries, Remote Control, Control Bus Cable