Class XD amplification – Cambridge Audio's 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 world.
Serious power – 200W into 8 Ohms stereo mode is serious power. But for those with bigger plans, the 851W is usable in a mono bridged configuration with each amplifier delivering 500W RMS.
Two toroidal transformers – Separate, high-end transformers for the power amplifier and input and other circuitry ensure audio performance is unaffected by the dramatic current output swings required to drive demanding speakers, by keeping power supplies entirely separate.
Terrapin impedance buffering modules – Cambridge Audio's 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 – unheard of at this price point.
CAP5 proprietary protection – Protects the integrity of your system by avoiding DC spikes, overheating, short circuits or clipping.
Integration – Smart auto-standby mode detects incoming audio signals to simplify integration with Cambridge Audio preamplifiers.
All-metal chassis – Including extensive use of aluminium to create massive structural rigidity, careful damping and control of acoustic resonance.
|Cambridge Audio's Class XD amplification with 12 output transistors per channel combines the best of Class A and AB amplification|
|Separate toroidal transformers for power amp and input/other circuitry|
|Cambridge Audio's Terrapin impedance buffering modules – separating amplifier and signal impedance|
|200W into 8 Ohms stereo mode or 500W RMS per amp mono bridged mode|
|Cambridge Audio's CAP5 protection from DC spikes, overheating, clipping etc.|
|<0.5W smart auto-standby mode for integration with preamplifiers|
|All metal chassis with premium components, creating massive structural rigidity, careful damping and control of acoustic resonance.|
|Remote Control – Compatible with the entire 851 range|
|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
|Frequency response||5Hz – 80kHz|
|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|
|Max. power consumption||2400W|
|Standby power consumption||Standby <0.5W|
|Dimensions (H x W x D)||148 x 430 x 365mm (5.8 x 16.9 x 14.4”)|