Cloud Electronics CX462 - Manual (Page 19)

CX462 Audio System Controller Setup And Installation Guide
CLOUD ELECTRONICS LIMITED
Outputs
11 General Specifications
12 Troubleshooting
12.1 Ground/Earth Loops
Despite your best efforts, if the completed sound system 'hums' you probably have a 'ground
loop'; the offending signal source can be found 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 CX462.
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 is
derived from a second device (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 diagrams below)
12.2 Connecting balanced signals to unbalanced line
inputs
We recommend the use of a transformer to convert a balanced signal to an unbalanced
signal suitable for direct connection to the CX462 line inputs. The transformer should be
mounted close to the CX462 and the unbalanced output lead should be kept as short as
possible. Where both the source and destination units are earthed, it is important to isolate
the primary and secondary windings to avoid a potential ground loop; if there is any doubt
about this, we suggest that the balanced cable screen is not connected at the transformer
end. RS Components part 210-6447 is a suitable transformer for this application we
recommend that the screening can (part number 210-6469) also be fitted to the transformer;
Canford Audio supplies a similar transformer (part number OEP Z1604). All transformers
should be wired to give a ratio of 1:1.
13 V3 280904
Nominal output level 0dBu
Minimum load impedance 600Ω
Maximum output level +20dBu
Power Input 230V/115V ±10%
Fuse Rating T100mA 230V
T200mA 115V
Fuse Type 20mm x 5mm 250V
Dimensions 482.60mm x 44.00mm(1U) x 152.5mm
Weight(kg) 2.5