来自剑桥Cambridge官方网站的评论：
Cambridge Audio breaks new ground with an entirely new class of amplifier in the shape of the 840A which marks the zenith of Cambridge Audio’s critically acclaimed Azur line-up.
Embracing Cambridge Audio’s patent pending proprietary Class XD™ technology, the 840A brings together the quality of Class A amplification, the power economy of Class B designs, and most amazingly of all, avoids many of the distortion pitfalls inherent in Class AB designs.
Completely separate pre-amp and power amp toroidal transformers and circuits make the 840A effectively a pre and power amplifier combination in one chassis
Another enormous benefit is its ability to integrate seamlessly with a home cinema system. Fixed level inputs allow the 840A to provide the front channel amplification to systems which use an AV receiver. The receiver continues to provide centre and rear amplification.
In addition to this innovative technology, the 840A uses an extremely sophisticated resistor ladder and relay attenuator for volume control and the same high quality relay switches for input selection. This enables high isolation between inputs, very accurate channel balance and leaves the amplifier completely free from the distortion associated with conventional semiconductor switching and volume control.
As with all Azur products, the foundation of the Azur 840A's is a bespoke chassis. This comprises an incredibly thick 7mm front panel and extruded side panels, both fashioned from aluminium, which combine with a 2mm formed steel base plate and specially designed vibration absorbing feet. The result is an ultra rigid, low resonance, acoustically dampened platform for the electronics to sit in.
Great attention has been paid to ensuring that all functions can be operated from the stunning aluminium-faced Azur Navigator remote. As well as offering full control over all the 840A's features and functions, this neat handset also enables track skip plus play and pause of iPods™ connected to Apple's iPod Universal Dock
Azur 840A features
Patent pending proprietary Class XD technology
Oversized low flux toroidal transformers
120 watts per channel (8 ohms)
200 watts per channel (4 ohms)
Completely separate pre-amp and power amp toroidal transformers and circuits make the 840A effectively a pre and power amplifier combination in one chassis
8 audio inputs - including 1 with balanced connections
Sophisticated resistor ladder and relay based attenuator for volume/balance control
Two pairs of very high current output transistors per channel
Twin rectifiers and separate transformer taps for dual mono operation of the left and right power amplifiers
RS232 port, IR emitter In and Control Bus In/Out for seamless integration with custom install systems
A-BUS™ / Incognito™ Ready connections compatible with Cambridge Audio’s new Incognito multi-room keypads or other A-BUS compatible keypads allow the 840A to form the hub of a simple but highly effective 3 zone multi-room system
Fixed level inputs allow the 840A to provide the front channel amplification when integrated with home cinema systems that use an AV processor
Cambridge Audio proprietary CAP5™ protection system
Nameable inputs, backlit LCD screen
Extruded aluminium side panels and solid aluminium front panel plus an ultra rigid, acoustically dampened chassis
Navigator style Azur remote control which also controls Azur CD players plus the Apple Universal Dock
Available in silver or black
剑桥840A技术参数
剑桥专利技术Class XD™ 介绍
At the core of the 840A’s strength is a patent pending, Class XD (crossover displacement) technology.
This unique design gives pure Class A operation at low levels, moving smoothly into an enhanced version of Class B at higher levels. This system should not be confused with Class AB, which inherently generates greater distortion at high levels than a pure Class B design.
XD technology feeds a controlled current into the output stage in a new way so that the usual Class B crossover point no longer occurs at zero volume - the worst possible position in terms of distortion – but at a significant output level.
The result is a smooth and linear transition between the two modes of operation, which differs significantly from the abrupt, distorted gain transition of a Class AB amplifier.
来自剑桥Cambridge中港澳地区总代理威达公司官方网站的评价：
劍橋azur系列自推出市場以來，一直深受用家歡迎，世界各地一致好評如潮，尤以 azur640A合併功放及640C鐳射CD唱機最受音樂發燒友歡迎，Version2版本蒲推出即獲各界最高讚譽，成為當今最熱門的入門級合併功放及鐳射CD唱機。
劍橋亦照顧到入門用家對器材升級上的渴求，突破性率先推出azur840A ClassXD™ 合併式功放。
-專利註冊Class XD技術，融合A類及B類線路之優點
-120W x2 8 ohms , 200Wx2 4 ohms
-完全獨立環型供電牛分開供前級及後級使用，真正雙單聲道功放。
-梯級電阻式音量制(一般只應用於極品前級控音器)
-每組輸入均可調較輸入音量以配合AV系統
-8組輸入包括XLR及RCA
-7mm特厚鋁合金面板
-4.5”x16.9”x15.2”(HxWxD)
-淨重33磅
Azur 840A features
Patent pending proprietary Class XD technology
Oversized low flux toroidal transformers
120 watts per channel (8 ohms)
200 watts per channel (4 ohms)
Completely separate pre-amp and power amp toroidal transformers and circuits make the 840A effectively a pre and power amplifier combination in one chassis
8 audio inputs - including 1 with balanced connections
Sophisticated resistor ladder and relay based attenuator for volume/balance control
Two pairs of very high current output transistors per channel
Twin rectifiers and separate transformer taps for dual mono operation of the left and right power amplifiers
RS232 port, IR emitter In and Control Bus In/Out for seamless integration with custom install systems
A-BUS™ / Incognito™ Ready connections compatible with Cambridge Audio’s new Incognito multi-room keypads or other A-BUS compatible keypads allow the 840A to form the hub of a simple but highly effective 3 zone multi-room system
Fixed level inputs allow the 840A to provide the front channel amplification when integrated with home cinema systems that use an AV processor
Cambridge Audio proprietary CAP5™ protection system
Nameable inputs, backlit LCD screen
Extruded aluminium side panels and solid aluminium front panel plus an ultra rigid, acoustically dampened chassis
Navigator style Azur remote control which also controls Azur CD players plus the Apple Universal Dock