Rear panel connections
Power On/Off
Switches the 851C on and off.
Mains Voltage Selector Switch (CU version only)
Switches the 851C mains voltage between 100V and 115V.
Note:
For use by Cambridge Audio service personnel only!
Power Socket
Once all other connections are made, connect the supplied power cable
to the 851C power socket and to an appropriate mains socket. The 851C
is now ready for use.
RS232C Interface
The RS232C interface enables external serial control of the 851C in
custom installation applications. A command set is available on the
Cambridge Audio website at www.cambridge-audio.com. The RS232
interface can also be used by Cambridge Audio service personnel for
software updates.
IR (Infra Red) Emitter In
A 3.5mm mini-jack socket that enables modulated IR commands from
multi-room or IR repeater systems to be received by the 851C.
Note:
Commands received by the IR Emitter In socket are not looped out
of the Control Bus. Refer to the ‘Custom Installation’ section for more
information.
Control Bus
In
– An RCA phono socket that enables un-modulated commands from
multi-rooms systems or other components to be received by the 851C.
Out
– An RCA phono socket that provides control bus output commands
for further downstream units.
Digital Outputs
The 851C digital outputs enable a separate DAC (digital to analogue
converter) or digital recording device to be connected. Refer to the
‘Operating instructions’ section for more information.
Three concurrent digital outputs are available. Note these outputs pass
through the currently selected audio source un-processed, i.e. no volume
control or up-sampling is performed on the digital outputs.
Balanced AES/EBU
– For external devices incorporating a balanced
(AES/EBU) digital input.
Note:
The acronym “AES/EBU” refers to the Audio Engineering Society
and the European Broadcast Union.
Coaxial
– To obtain best results, use a high quality 75 ohm digital RCA
interconnect cable (not one designed for normal audio use).
Toslink Optical
– Use a high quality TOSLINK fibre optic interconnect
cable designed specifically for audio use.
USB Interface
A USB B type socket is fitted to the 851C to enable the playback of audio
from a personal computer running either Microsoft Windows or Apple
Mac OS X operating systems. Some builds of Linux are also suitable.
Note:
Always use a high quality USB connection cable certified as USB Hi-
Speed. USB cable connections longer than 3m may result in inconsistent
audio performance.
Ground Lift Switch
The Ground Lift Switch enables the USB interface earth to be
disconnected from the 851C chassis earth. Disconnecting (lifting) the
earth can be useful if electronic hum is heard through the speakers
when the USB input is selected. The switch should otherwise be left in
the Ground position.
- Digital Inputs 1 & 2
The 851C has three digital inputs in total. Inputs 1 and 2 feature both
S/PDIF co-axial and Toslink optical sockets.
For each input you can use whichever is most convenient, but not both
at the same time.
Coaxial
– Use a high quality 75 ohm digital RCA Phono interconnect
cable (not one designed for normal audio use). This input is suitable for
16-24 bit content up to 192kHz.
Toslink Optical
– Use a high quality TOSLINK fibre optic interconnect
cable designed specifically for audio use. This input is suitable for 16-24
bit content up to 96kHz (Toslink is not recommened at 192kHz sampling
rates).
AES/EBU Digital Input
For sources with a balanced (AES/EBU) digital output. This input is
suitable for 16-24 bit content up to 192kHz.
Unbalanced Audio Output
A conventional RCA phono stereo output for connection to the line-level
inputs of an amplifier. Use a high quality stereo RCA phono interconnect
cable intended for analogue audio signals.
Balanced Audio Output
The 851C features balanced outputs on two XLR sockets. Balanced
outputs provide slightly better audio performance and can reject
cable-borne noise and interference when used with equipment with
balanced inputs.
Note:
XLR connectors should be wired as follows:
Pin 1: Ground
Pin 2: Hot (in-phase)
Pin 3: Cold (phase-inverted)
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851C
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ENGLISH
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Always turn the Volume to minimum, switch to another
input or turn the 851C off before plugging/unplugging
cables to the USB input or whilst booting up/shutting
down your PC/Mac.
