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AA-series Audio Amplifiers Manual for DVC-AO Applications —
P/N 52526:B 8/13/2019
Amplifying Audio Messages
Adjusting the Audio Gain Level
3.6.1 AA-100/AA-120 Circuit Board Layout
Layout of the AA-100/AA-120 circuit board and identification of its operating components:
3.6.2 AA-100/AA-120 LED Conditions
Conditions that cause each AA-100/AA-120 System Status Indicator LED to light:
3.6.3 Selecting the Backup Tone on AA-100/AA-120
The AA-100 and AA-120 Audio Amplifiers automatically produce a backup tone when the low-level audio input is lost. You can select
the backup tone by following these steps.
1.
Locate SW1 in the lower right-hand corner of the AA-100 or AA-120 (Figure 3.10).
2.
Set SW1 to Hi/Lo or Slow Whoop as the default backup tone as shown below.
3.7 Adjusting the Audio Gain Level
An audio amplifier contains a multi-position rotary switch that lets you adjust the gain of the audio output signal. This adjustment com-
pensates for audio line losses. After correct adjustment, an audio amplifier can produce its maximum rated output power of 25 Vrms
(AA-30, AA-120) or 70.7 Vrms (AA-100).
Normal Level LED
Incorrect Level LED
Battery Trouble LED
Brownout LED
Speaker Trouble LED
Input Trouble LED
Amplifier Trouble LED
Audio Gain Rotary Switch
SW1 - Backup tone switch
R100 - Resistor (cut for
four-wire supervision)
AA
-1
20
.w
mf
R107 - Resistor (cut for
stand-alone mode)
Figure 3.10 AA-100/AA-120 LED and Switch Locations
LED
Lights when
normal level
The audio amplifier is adjusted properly and operating correctly during normal (non-alarm) conditions.
incorrect level
The audio amplifier is not sensing low-level audio, or the gain is not adjusted properly.
battery trouble
The battery voltage is below a sufficient level.
brownout
The AC power source is below a sufficient level. During a complete loss of AC power, no LEDs will light on the
AA-100/AA-120.
speaker trouble
An open circuit condition occurs in the four-wire, high-level output.
input trouble
A loss of the low-level audio input signal, or an amplifier failure.
amplifier trouble
A loss of the low-level audio input signal, or an amplifier failure.
Table 3.2 AA-100/AA-120 LED Functions
Hi/Lo
Slow Whoop
Figure 3.11 SW1 Backup Tone Switch
