User guide

Z4
II
& Z8
II
:
Installation and User Guide 9
22/10/04 V9
23 Controlling the music functions using external DC control
The Cloud Z4 and Z8 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-6 control plate can be used to feed two separate control
voltages into the mixer on a zone by zone basis. 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 source selection.
Control of music level
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 +15V 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.
Music source selection
Here are the details of the music source select control voltages (pin 3) required to switch the
six line input signals:
Off >+9.0V
Line 1 +7.5V
Line 2 +6.0V
Line 3 +4.5V
Line 4 +3.0V
Line 5 +1.5V
Line 6 0V
With no external connection to pin 3, an internal 15k resistor connected to +15V 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 would like to fix the music signal to a particular line input, wire a fixed resistor from the
table below between pins 1 & 3 on the remote control connector:
Line 1 16k
Line 2 11k
Line 3 6k8
Line 4 3k9
Line 5 1k8
Line 6 shorting link
If the control voltage source is not isolated from the power earth, there is a small risk of
creating a ‘ground loop’ by linking the mixer technical ground (0V) to the ground (0V) of the
equipment providing the control voltages. To minimise this risk of a ground loop occurring,
we suggest that all pieces of equipment be positioned in close proximity and supplied from
the same power outlet.