4
Thank you for purchasing this Azur 840W Class XD™ power amplifier.
We hope that you will enjoy many years of listening pleasure from it.
The 840W features our unique proprietary amplifier topology; Class XD,
designed to eliminate crossover distortion at low signal levels.
By actively displacing the crossover point this technology creates a
region of pure Class-A operation where the crossover zone would
otherwise be before moving into an enhanced form of Class B at higher
levels. It should not be confused with Class AB, which gives a small area
of Class A, but at the cost of higher distortion as soon as the signal level
moves outside the AB area. Class XD circuitry not only removes
crossover distortion from the zero-crossing point but also reduces
distortion in other parts of the amplifier's output range.
A white paper on this patent pending technology is available on our
website:
www.cambridge-audio.com
Please note that because of the Class XD technology the 840W runs
slightly warmer than a conventional Class B/AB amplifier and the
ventilation slots on the top of the unit must not be obstructed.
Other features include a low resonance acoustically damped chassis for
freedom from distortion inducing vibrations. Four pairs of very high
current output transistors per output are used for excellent load driving
ability, plus the unique fifth output transistor pair per channel that
provides the business end of the Class XD circuitry. High quality
polypropylene signal capacitors are used throughout, whilst multiple
gold plated copper bus-bars provide very low impedance conduits for the
power circuits and all resistors are 1% tolerance metal-film types.
Balanced audio input connections are fitted for the highest fidelity and
all inputs have loop outputs. The loop outputs can be used with the
840W’s Bi-Amp Mono and Bridged-Mono modes to allow two or more
840Ws to be used in very high quality systems.
The 840W features separate transformer secondaries for left and right
channels, twin rectifiers and separate PSUs for dual mono operation of
the left and right power amplifiers.
Your power amplifier can only be as good as the system it is connected
to. Please do not compromise on your pre-amplifier, source equipment,
speakers or cabling. Naturally we recommend models from the
Cambridge Audio Azur range, particularly the matching 840E pre-
amplifier. These have been designed to the same exacting standards as
this amplifier. Your dealer can also supply excellent quality Cambridge
Audio interconnects to ensure your system realises its full potential.
Thank you for taking the time to read this manual; we do recommend
you keep it for future reference.
Matthew Bramble,
Cambridge Audio Technical Director
and the 840E/840W design team
Contents
Introduction
Important safety instructions .....................................................................2
Limited warranty..........................................................................................3
Contents.......................................................................................................4
Introduction .................................................................................................4
Rear panel connections..............................................................................5
Front panel controls ....................................................................................6
Connections.................................................................................................7
Unbalanced stereo connections .....................................................7
Balanced stereo connections..........................................................7
Power syncing...................................................................................7
Advanced connections................................................................................8
Bi-wired stereo connections ............................................................8
Bi-amped dual mono connections ..................................................9
Bridged dual mono connections .....................................................9
Custom installation use............................................................................10
Technical specifications ...........................................................................10
Troubleshooting.........................................................................................11
Visit www.cambridge-audio.com and register to receive notification of future
hardware and software releases.
This guide is designed to make installing and using this product as easy as
possible. Information in this document has been carefully checked for accuracy at
the time of printing; however, Cambridge Audio's policy is one of continuous
improvement, therefore design and specifications are subject to change without
prior notice. If you notice any errors please feel free to email us at:
support@cambridgeaudio.com
This document contains proprietary information protected by copyright. All rights
are reserved. No part of this manual may be reproduced by any mechanical,
electronic or other means, in any form, without prior written permission of the
manufacturer. All trademarks and registered trademarks are the property of their
respective owners.
Class XD Technology International Patent Pending Cambridge Audio Ltd.
© Copyright Cambridge Audio Ltd 2007
