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Quite literally in a class of its own, the new 851A Class XD integrated amplifier is designed to offer power, finesse and astonishingly low distortion. At its heart lies our own proprietary Class XD technology, which has been refined and enhanced since its inception in the 840 series, allowing even greater musical detail to be delivered to your speakers...Read more
Greece, April 2013
Capable of delivering an enormous 120 watts of high-quality power, it benefits from two audiophile-grade toroidal transformers: one for the sensitive preamp section and one for the power stages allowing the 851A to deliver its immense output without stress. This incredible speaker-taming amount of power can be precision-controlled with another innovation found in the 851A - the new fully balanced silicon gate volume control, which gives very fine adjustment across the volume range and highly accurate channel-balancing.
Because everyone's needs are different, the 851A offers two main types of connectivity: the more commonly found RCA/Phono inputs, plus two pairs of fully balanced XLR connections. Our matching 851C upsampling CD player also features both types of connection, allowing you to connect your system in the very highest quality possible.
Speaking of flexibility, you can even control your iPhone, iPad or iPod using the 851 Series remote control when they're docked in our matching iD100 digital dock.
Unlike many high end amplifiers which excel in one area over another, we believe the 851A offers the perfect combination of high performance, flexibility and ease of use. It's designed to take your listening experience to an entirely different level and we invite you to audition our best amplifier to date at your nearest Cambridge Audio specialist.
Class XD amplification designed to eliminate crossover distortion at low signal levels
|New balanced volume topology controllable in 1dB steps, giving very fine control, and superbly accurate channel balance|
|Audiophile grade oversize toroidal transformer and substantial extruded heatsink allowing 2 x 120 Watts RMS into 8 Ohms or 2 x 200W into 4 ohms.|
|Separate transformer taps for left and right channels, twin rectifiers and separate PSUs for dual mono operation of the left and right power amplifiers|
|A separate toroidal transformer supplies the preamp making the 851A effectively a Pre and Power amp combination in one box|
|CAP5 protection technology for trouble free operation|
|Acoustically damped full metal chassis with thick brushed aluminium front panel|
|Customisable front panel display|
|Balanced and unbalanced analogue audio inputs for superior connectivity|
|Eco-friendly <0.5W Standby power consumption|
|Available in black and silver finishes|
Class XD, a proprietary Cambridge Audio technology, is a unique amplifier circuit design created to offer the optimum sound quality currently available from existing amplifier configurations, whilst retaining the high power levels required for truly dynamic performance. It was conceived by our London-based engineering team to combine the best of both worlds from Class A and Class A/B amplifier operation.
Class XD (crossover displacement), gives the benefits of pure Class A operation at low levels and eliminates the distortion associated with conventional Class B operation as the fragile audio signal passes though the zero crossing point from transistor to transistor. Distinct from Class AB, XD technology feeds a controlled current into the output stage in such a way that the usual Class B crossover points no longer occur either side of zero volume - the worst possible position in terms of distortion – but displaced to a point where the transfer functions of the transistors are better matched, at a significant output level where it is less audible. The system operates outside of the feedback loop so is not directly involved in the signal amplification itself.
The result is a smooth and linear transition between the two key operating modes, Class A and B.
The benefits of this approach give the sonic refinements of Class A operation and the uncompromising efficiency and power of Class B operation. In fact, the new 851A delivers a gigantic 120 watts per channel - enough for the most demanding speaker set-up.
Greece, April 2013
UK, February 2013
New Zealand, January 2013
EU, August 2012
UK, August 2012
Netherlands, December 2012
UK, November 2012
New Zealand, November 2012
UK, October 2012
France, October 2012
120W RMS into 8 Ohms
200W RMS into 4 Ohms
200W RMS into 4 Ohms
< 0.001% 1 kHz at 80% of rated power
< 0.01% 20 Hz - 20 kHz at 80% of rated power
2 x balanced XLR
8 x RCA inputs
|Frequency response:||10 Hz - 50 kHz +/- 1 dB|
|S/N ratio (ref 1w):||> 93 dB (ref 1W/8 Ohm)|
Inputs 1 and 2 (balanced) 20 kOhm
Inputs 1-7 unbalanced 20 kOhm
Rec Input 20 kOhm
|Power amp damping factor:||> 110 at 1 kHz|
|Max. power consumption:||800W|
|Min. power consumption||Active (no signal) 70W|
|Standby power consumption:||Standby <0.5W|
Max bass boost/cut +/- 10 dB at 10 Hz
Max treble boost/cut +/- 7.5 dB at 20 kHz
|Dimensions (W x H x D):||430 x 115 x 385mm (16.9 x 4.5 x 15.2”)|