Connecting Mains Power - ALLEN & HEATH WZ16:2DX User Manual

Connecting Mains Power

W AR NING - THIS APPAR ATUS MUST BE E AR THE D.
TO R E DUCE THE R ISK O F FIR E O R E LE CTR IC SHO CK
DO NO T E X PO SE THIS APPAR ATUS TO R AIN O R MO ISTUR E .
CAUTI ON
AVIS: R ISQ UE DE CHO C E LE CTR IQ UE - NE PAS O UVR IR .
FUSE
100 - 240V~ T500mA 250V 20mm
W AR NING : FO R CO NTINUE D PR O TE CT IO N AG AINST R ISK O F FIR E
R E PLACE FUSE W ITH SAME TY PE AND R ATING
ATTE NTIO N: R E MPLACE R LE FUSIBLE AVE C UN DE S ME ME S CAR ACT E R ISTIQ UE S.
E
ARTHING
The connection to earth (ground) in an audio system is important for two reasons:
1. SAFETY - To protect the operator from high voltage shock associated with the AC mains supply
feeding the system, and
2. AUDIO PERFORMANCE QUALITY - To minimise the effect of earth (ground) loops which result
in audible hum and buzz, and to shield the audio signals from interference.
For safety it is important that all equipment earths are connected to mains earth so that exposed
metal parts are prevented from carrying high voltage which can injure or even kill the operator. It is
recommended that the sound engineer check the continuity of the safety earth from all points in the
system including microphone bodies, guitar strings, multicore cases, equipment panels ...
The same earth is also used to shield audio cables from external interference such as the hum
fields associated with power transformers, lighting dimmer buzz, and computer radiation. Problems
arise when the signal sees more than one path to mains earth. An 'earth loop' (ground loop)
results causing current to flow between the different earth paths. This condition is usually detected
as a mains frequency audible hum or buzz.
To ensure safe and trouble-free operation please observe the following:
• Do not remove the earth connection from the console mains plug. The console chassis is
connected to mains earth through the power cable to ensure your safety. Audio 0V is connected to
the console chassis internally. If problems are encountered with earth loops operate the audio
'ground lift' switches on connected equipment accordingly, or disconnect the cable screens at one
end, usually at the destination. It is useful to carry ground lift cable adapters such as short XLR
male to female leads with pin 1 disconnected.
• Avoid running audio cables next to mains, computer or lighting cables, or near thyristor
dimmer and power supply units. If unavoidable, cross these at right angles.
• Use low impedance sources such as microphones rated at 200 ohms or less to reduce
susceptibility to interference. The console outputs are designed to operate at very low impedance
to minimise interference problems.
• Use balanced connections where possible as these provide further immunity by cancelling
out interference that may be picked up on long cable runs. To connect an unbalanced source to a
balanced console input, link the cold input (XLR pin 3 or jack ring) to 0V earth (XLR pin 1 or jack
sleeve) at the console. To connect a balanced console output to an unbalanced destination, link
the cold output to 0V earth at the console.
• Use professional quality cables and connectors and check for correct wiring and reliable
solder joints.
• If you are not sure ... Have your system checked by a competent engineer, or contact your
local Allen & Heath agent for advice.
11
Refer to the SAFETY WARNING on page 5 of this Guide.
Check that the correct mains lead with moulded plug has been
supplied with your console. Read and understand the warnings
and instructions printed on the rear panel and reproduced here.
SUPPLY VO LTAG E R ANG E :
The power supply accommodates mains voltages within the
~
100 - 240V
AC MAINS IN ~
47-63Hz ~ 30W MAX
range 100-240V without changing any fuses or settings.
O FF O N
It is standard practice to turn connected power amplifiers down
or off before switching the console on or off. Ensure that the
IEC mains plug is pressed fully into the rear panel socket before
R E FE R TO USE R G UIDE BE FO R E CO NNE CTING SUPPLY
NO USE R SE R VICE ABLE PAR TS INSIDE .
switching on.
R E FE R SE R VICING TO Q UALIFIE D SE R VICE PE R SO NNE L.
WZ16:2DX WZ12:2DX U
AND
G
SER UIDE