CX261 Installation and User Guide v1.5
21
The diagram below shows the locations of the CX261’s internal PCB jumpers (not to scale).
If any jumpers need to be changed, turn the Zone Mixer off and disconnect it from the mains. Undo the 6 screws securing
the top cover of the unit and remove it. Use a pair of small pliers to gently remove the jumpers from the PCB headers and
reposition them as required.
The diagram also shows the locations of the socket for the optional loudspeaker EQ cards.
SUB-BOARD
SUB-BOARD
J7
J7
J9
J6
J14
J8
J15
J11
J13
J12
J10
J4
J3
J5A
J5B
J1
J2
J16
LOUDSPEAKER
EQ MODULE
CONNECTOR -
LEFT CHANNEL
LOUDSPEAKER
EQ MODULE
CONNECTOR -
RIGHT CHANNEL
FRONT OF UNIT
KEY
2-pin header; jumper may
be present or absent
3-pin header: jumper may be
positioned on pins 1 & 2, or pins 2 & 3
Black end indicates
factory default setting
Motherboard jumper locations
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 “Music Sources” on page 10
).
EMC considerations
The Cloud CX261 fully conforms to the relevant electromagnetic compatibility (EMC) standards and is 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 equipment chassis and the line input leads are kept as short as possible.
