Contents
Thank you for purchasing the Azur 851C Upsampling Compact Disc
Player / DAC / Digital Preamp. The 8 series range is fundamental to our
commitment to the continual development of the Azur range. We hope
that you will appreciate the results and enjoy many years of listening
pleasure from it. Like all Cambridge Audio products, the 851C adheres
to our three core principles – stunning performance, ease of use and
incredible value.
The 851C incorporates numerous advanced technologies and
features. Key to its abilities is ATF2™ (Adaptive Time Filtering) our
second generation up-sampling process - developed in conjunction
with Anagram Technologies of Switzerland. This process intelligently
interpolates all incoming audio data (such as 16-bit/44.1kHz from CD)
to 24bit/384kHz through the use of a 32-bit Analog Devices Black Fin
DSP (Digital Signal Processor). The ATF2 system applies polynomial
curve fitting interpolation, and incorporates a time domain model that
allows data buffering and re-clocking to almost completely eradicate
digital jitter, helping to ensure the best possible sound quality. Our new
ATF2 noise shaping algorithm now also provides enhanced linearity with
24-bit sources.
Two very high quality Analog Devices AD1955 24-bit DACs (Digital to
Analog Converters) are used in dual differential mode. Each channel
has its own DAC to process information and completely separate and
symmetrical analog filter circuitry is implemented. These allow both
left and right channel circuitry to operate identically, ensuring the
851C delivers fantastic sound-staging and stereo imaging properties.
All filtering from DACs to output is also fully differential in nature. This
fully balanced configuration largely rejects the already very low noise
and distortion products present in the DACs and filters and provides
an unprecedented level of performance. Balanced (XLR) outputs are
fitted as well as summed conventional unbalanced phono/RCA outputs.
Automatic DC servo circuits null all DC offsets allowing no capacitors in
the signal path.
For this new model two 24-bit capable digital inputs are fitted allowing
other digital sources to be brought into the 851C.
Also a 24-bit isochronous USB audio interface is provided that enables
the 851C to play audio from a personal computer / laptop. This can
handle up to 24-bit/96kHz content from most Windows, Mac and Linux
builds. In certain circumstances up to 24-bit/192kHz material can
also be supported. See later section on Mac/PC/Linux setups and in
particular our own free Windows driver.
Digital volume and output mute functions are incorporated that enable
the 851C to operate as a combined CD player, DAC and digital pre-
amplifier that can be connected directly to a separate power amplifier
if desired.
In addition to these audiophile features Control Bus Input/Output, IR
Emitter Input and RS232 control are provided to make it easy to integrate
this unit into Custom Installation systems if desired.
A new 8-series casework combines massive structural rigidity with
careful damping and control of acoustic resonance. An Azur Navigator
remote handset is also provided, giving full control of your CD player,
Azur amplifiers and our iD100 digital iPod/iPad/iPhone dock in an
attractive and easy to use handset.
Your 851C can only be as good as the system it is connected to. Please
do not compromise on your amplifier, speakers or cabling. Naturally we
particularly recommend amplification from the Cambridge Audio Azur
range, and in particular the 851A Integrated Amplifier which has been
designed to the same exacting standards as the 851C. Your dealer can
also supply excellent quality Cambridge Audio interconnects to ensure
your system realises its full potential.
Thanks 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 851C design team
Introduction
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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.
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.
© Copyright Cambridge Audio Ltd 2012
Cambridge Audio and the Cambridge Audio logo are
trademarks of Cambridge Audio.
Other brands mentioned are trademarks of their respective
owners and are used for reference purposes only.
2
Introduction .................................................................................................2
Important safety instructions .....................................................................3
Limited warranty ..........................................................................................4
Front panel controls ....................................................................................6
Remote control ............................................................................................7
Apple device compatibility ..........................................................................7
Operating instructions ................................................................................8
Filters ........................................................................................................ 12
Custom installation (C.I.) use .................................................................. 14
Troubleshooting ........................................................................................ 14
Technical specifications ........................................................................... 15
