Cambridge Audio 840A Manuale Utente

840A Class XD integrated amplifier

Azur Class XD integrated amplifier  3

Thank  you  for  purchasing  this  Azur  840A  Class  XD  Integrated  Amplifier.

This   unit   is   part   of   our   new   '8'   Series   taking   Cambridge   Audio   to   new

levels   of   audio   excellence   as   part   of   our   commitment   to   the   on-ggoing

development   of   the   Azur   range.   We   hope   that   you   will   appreciate   the

results  and  enjoy  many  years  of  listening  pleasure  from  it.

For the 840A we developed many new circuits and components, with

many parts being designed specifically for this model. A unique

proprietary to Cambridge Audio patent pending amplifier topology has

even been developed called Class XD™ which can eliminate crossover

distortion at low signal levels. 

This technology creates a region of pure Class-A operation where the

crossover zone would otherwise be. It should not be confused with Class

AB, which gives a small area of Class A, at the cost of higher distortion

as soon as signal levels moves outside it. Class XD circuitry not only

removes crossover distortion from the zero-crossing point but also

reduces distortion in the other parts of the amplifier's output range. A

white paper on this technology is available on our website:

www.cambridge-audio.com.

Please note that because of the Class XD technology the 840A runs

slightly warmer than a conventional Class B/AB amplifier and the

ventilation slots on the top of the unit must not be obscured.

Other features include the use of precision networks of resistors and

relays for the volume and balance control rather than the more common

solid-state or volume potentiometer schemes. Volume is controllable in

1 dB steps over most of the range, giving very fine control, an accurate

logarithmic law and superbly accurate channel balance. Input switching

is also by high quality relays.

The 840A features separate transformer secondaries for left and right

channels, twin rectifiers and separate PSU's for dual mono operation of the

left and right power amplifiers. A separate transformer supplies the preamp

making the 840A effectively a Pre and Power amp combination in one box.

Input 1 features a balanced input using XLRs giving optimal

performance with equipment such as the matching 840C Upsampling

CD player which feature balanced outputs. 

A completely new casework has been designed which combines

massive structural rigidity with careful damping and control of acoustic

resonance. An Azur Navigator remote control is also provided, giving full

remote control of your amplifier in an attractive and easy to use

handset.

We have also added many new features, including support for multi-

room use. By plugging in one or two external Cambridge Audio Incognito

keypads and a power supply unit your amplifier can become the hub of

a simple multi-room system. In addition, 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.

Your amplifier can only be as good as the system it is connected to.

Please do not compromise on your source equipment, speakers or

cabling. Naturally we particularly recommend models from the

Cambridge Audio Azur range. 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.

Thanks for taking the time to read this manual; we do recommend you

keep it for future reference.

Matthew Bramble
Technical Director

INTRODUCTION