Cloud Z4MK3, Installation And User Manual

Page: 24 / 32

Z4-8
MK3
Installation and User Guide v1.2 24
PSU capability and optional device current consumption
In addition to supplying the Zone Mixer’s circuitry, the internal PSU has the capacity to power some additional items which may
form part of a complete system. These include LM-2 active remote input modules (via the Facility Port), loudspeaker EQ cards
(fitted internally), and possibly a PM Series paging microphone (powered via the Access Port).
The maximum current capacity of the PSU available for powering optional items is 120 mA (Z4
MK3
)
or 190 mA (Z8
MK3
)
.
Current consumption of the various items is listed in the table below.
ITEM CURRENT PER UNIT
LM-2 mic/line input module 12 mA
PM-4 paging microphone 72 mA
PM-8 paging microphone 83 mA
Loudspeaker EQ cards (each) 6 - 34 mA*
*Model-dependent. See separate datasheets at www.cloud.co.uk
The installer should ensure that the total current drawn by all the optional items in a system does not exceed 120 mA (Z4
MK3
)
or 190 mA (Z8
MK3
)
.
Note that PSU performance will be degraded at ambient temperatures in excess of 35
°
C.
Ground loops
If, despite your best efforts, the completed sound system ‘hums’, you probably have a ‘ground loop’. The offending signal source
can often be identified by setting the volume control to minimum, then disconnecting the input leads (both left & right channels)
on each line input until the ‘hum’ disappears. This problem is often caused by terminating a screened input cable into a signal
source positioned a significant distance from the mixer. A good way of avoiding this potential problem is to use signal sources
(CD players and the like) that are double insulated with no connection to the mains supply earth. If a signal feed were derived
from a second mixer (a club or microphone mixer for example) it would be perfectly normal to expect this to be earthed; we
suggest that a transformer be used to isolate the signal and prevent a noisy loop (see page 10 ).
EMC considerations
The Cloud Z4
MK3
& Z8
MK3
fully conform to the relevant electromagnetic compatibility (EMC) standards and are technically well
behaved; you should experience no operational problems and under normal circumstances, no special precautions need to be
taken. If the unit is to be used within close proximity to potential sources of HF disturbance such as high power communications
transmitters, radar stations and the like, the performance of the mixer may be reduced; we suggest that the microphone cable
screen be connected to the shell of the equipment chassis and the line input leads are kept as short as possible.