Booster Output; Variable Output; Fixed Output; Dc Power - ADS 3120 Plus Operation Manual

Booster Output

Variable Output

Where a variable output is required this is available through the 5-pin DIN output socket
(see Rear Panel No.16 on Page 8). The output is dependent on all controls.
Pin
1 Variable output.
2 Screen.
Open collector to ground when a
3
priority signal is present.
4

Fixed output.

5 Ground.
Variable Output
Two phono sockets are available (see Rear Panel No.15 on Page 8). These are connect-
ed together internally and provide a variable output, output varies with the position of the
mixer and master level controls.

dc Power

The amplifier may be operated from a battery power source. Ensure correct polarity
connection when connecting batteries. The amplifier requires a 24Vdc source.

Facility Terminals

A 24Vdc 0.5A supply is provided on the rear panel in conjunction with Busy and Speak terminals.

dc Output

The two left terminals (see diagram below) provide a 24Vdc protected output, which can
be used to supply external devices (such as relays or line pre-amplifiers) up to 250mA.

Restoration

The two right terminals (see diagram below) can be used to drive LEDs in some
microphones to show that other microphones in the system are currently broadcasting.
Busy is used to indicate that the system has a priority running. Speak is used to indicate
that the chime has run and the user can speak now.
Another use for the busy terminal is volume restoration as used on many volume controls
and for the control of other external devices and relays.
When using external relays, ensure that a 'back EMF' diode is fitted to the relay or
damage to the amplifier or other connected equipment may result. ('Back EMF' is caused
by the collapsing magnetic field in the relay coil as the relay is switched off and depending
on the relay can produce very high voltages. The diode acts as a short circuit and
eliminates 'back EMF'. Use 1N4001 diode or equivalent).
Function
Page 11 of 16
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180 5-pin DIN socket