Specifications

0 / GATE OUT
0 LOGIC GROUND
01 MUTE IN
OVERRIDE IN
CcHAIRPERsoN7.s
CHANNEL
Loudspeaker Muting
In some applications, a loudspeaker is located near each
talker to provide audio reinforcement or to allow monitoring
of a telephone conversation or conference. Each
loudspeaker can cause feedback unless it is automatically
switched off whenever the talker near it speaks. To provide
this function, connect the Gate Out terminal of each channel
to a separate loudspeaker muting relay as shown in Figure
1
3. Recommended relays are Guardian 1345-1 51 20 or
1475-1 C-120, or Potter
& Brumfield R50-E2-YI-l2V or
R1 0-El -Y2-V185, or equivalent.
CHAIRPERSON-CONTROLLED MUTING
Each loudspeaker should be placed behind its associated
FIGURE 10
microphone to prevent the loudspeaker from gating on the
microphone. The loudspeaker volume should be low;
other-
Disabling the Gating Function [Bypass)
wise the microphone may not gate on reliably when the
To keep all the microphones on, wire all the Override In ter-
talker speaks.
minals together to a Logic Ground terminal [see Figure 1 I].
This is useful if it is desired to bypass the automatic function-
If the existing sound system uses 24-volt relays, they can be
ing and use the AMS mixer as an ordinary mixer.
driven with the AMS Gate Out using internal wiring
modifica-
tions described in the Internal Wiring Modifications section.
GATING BYPASS
FIGURE
11
GATE OUT
LOGlC GROUND
MUTE IN
OVERRIDE IN
Remote Channel-On Indication
The LED's above each Channel control light when that chan-
nel is gated on. These indicators can be used to identify the
talker or to indicate to each talker when his or her
microphone is on. To provide Channel-On indicators at loca-
tions remote from the mixer, connect
LED's and a 5-volt
power supply to the Gate Out terminals as shown in Figure
12. NOTE: To avoid switching clicks in the audio outputs,
do not ground the power supply negative terminal to the
audio system ground or rack ground.
IMPORTANT: If a single cable is to carry the AMS micro-
phone audio signal
and the dc power for the LED, separate
shielded pairs
must be used. Failure to carry the dc power
on a shielded pair may result in audible clicking due to
capacitive coupling between the dc power lines and the
AMS microphone lines.
i
GATE OUT
LOGlC GROUND
MUTE IN
0VERRIDE.IN
R= 150-300n
SUPPLY
POWER
OVERRIDE
IN^
LOUDSPEAKER MUTING F:gR
FIGURE 13 AMPLIFIER
"Filibuster" Mode
In normal operation, when several people talk, all their
microphones gate on so that no speech is missed. But with
the mixer wired for "Filibuster" action, a microphone that is
gated on prevents other microphones from gating on. Once
a microphone is on, other microphones cannot gate on until
the talker has paused long enough so that his or her
microphone has gated off. Thus, the person talking has the
floor and cannot be interrrupted.
To establish this function, perform the internal Mute to In-
hibit jumper change [see Internal Modifications section for
details]. Then connect all the Mute In terminals of the
modified channels together; connect all the Gate Out ter-
minals of the modified channels together, and connect the
Gate Out terminal of one modified channel to the Mute In
terminal of another modified channel [see Figure
141.
GATE OUT
LOGlC GROUND
MUTE IN
OVERRIDE IN
REMOTE CHANNEL-ON INDICATORS
FIGURE
12
FILIBUSTER" MODE
FIGURE
14