Cloud Electronics 44/50 - Manual (Page 11)

10 44/50: Installation and Operation Manual
29 Controlling the music functions using external DC control.
When fitted with the optional REM-4 module, the 44/50 can be used as part of an
automated sound system by controlling the music level and music source by an external
0-10V DC voltage. The 3-pole connector normally used to terminate the RSL-1 control
plate can be used to feed two separate control voltages into the 44/50. Pin 1 is a ground
(0V) termination common to both control voltages; this should be connected to the
technical ground (0V) of the voltage source. Pin 2 is the control voltage input for the
music level and pin 3 is used to control the music signal source selection.
Level Control
A maximum gain reduction of 60dB can be achieved with a control voltage of +10V; the
rate of attenuation is approximately 165mV per dB. A control voltage of zero realises unity
gain (full volume), however, with no external connection to pin 2, an internal 4k7 resistor
connected to the +15V power will ‘pull up’ the control voltage to provide maximum
attenuation. The output impedance of the control voltage source should be low enough to
overcome the influence of this resistor.
Source Select
Here are details of the source select control voltages (pin 3) required to switch the four
line input signals:
Off +6.00V
Line 1 +4.00V
Line 2 +3.25V
Line 3 +2.00V
Line 4 0.00V
With no external connection to pin 3, an internal 15k resistor connected to the +15V
power will ‘pull up’ the source select control voltage and the ‘off’ position will be selected.
The output impedance of the control voltage source should be low enough to overcome
the influence of this resistor. If you require, you can permanently set the music signal to
the Line 1 input by wiring a 20k resistor between pins 1 & 3 on the remote control
connector.
If the control voltages are not isolated, there is a small risk of creating a ‘ground loop’ by
linking the 44/50 ground with the ground of the equipment providing the control voltages;
we suggest that all pieces of equipment be positioned in close proximity to each other.
30 EMC Considerations
The Cloud 44/50 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, it is suggested
that the microphone cable screen be connected to the shell of the XLR type connector,
and the line input leads be kept as short as possible.