LT0372 Issue 1.10 21 March 2011 Page 1 of 4
PA0646
QE90 Audio Line Isolator Module ALIM9706
Installation and Operating Instructions
Description
The Vigilant® Audio Line Isolator Module ALIM9706 is an audio isolation and balancing/matching device
with variable or fixed gain. It was designed for use with QE90 and Microvac systems, and also for general
audio isolation purposes.
The ALIM9706 provides independent isolation of two audio signals (channels), with the gain separately
selectable for each channel.
The ALIM9706 can be used for various purposes, including:
As an isolation and/or line balancing transformer (with optional volume control) for background
music inputs connecting to the Local Inputs of QE90 Amplifiers, music input of T-GEN 50, etc. Refer
Fig.1 below.
To allow spurs on the WIP speech and PA speech busses in a networked QE90 system. Refer Fig.
4 and 5 below.
To provide the isolation and voltage reduction required when connecting the amplifier primary or
100V line output of a QE90, T-GEN 50 or similar system into the low level input of another amplifier
(or vice versa). Refer Figure 3 below.
Music Source 1
Music Source 2
ALIM9706
( See text for link
settings )
IN +
IN +
IN -
IN -
OUT +
OUT +
OUT -
OUT - IN
Amplifier 1
Amplifier 2
IN
IN
Figure 1 –Typical Use of ALIM for Background Music Isolation
Gain Settings
Each audio channel of the ALIM9706 can be set for one of four different gains (refer to Table 1 below):
If no volume control is required, links LK1 and LK2 on the ALIM9706 should be installed, and LK3
not installed. In this mode the ALIM9706 has unity gain.
When volume control is required, links LK1 and LK2 should be removed, and link LK3 installed in
the 2-3 position. In this mode the ALIM9706 has a maximum gain of about 0.3, but it can be
adjusted down to zero.
If one of links LK1 or LK2 is fitted and LK3 is installed in the 1-2 position, then a fixed gain of 0.04 is
selected.
If neither links LK1 nor LK2 are fitted and LK3 is installed in the 1-2 position, then a fixed gain of
0.02 is selected. This is suitable for fixed attenuation for 100W Microvac systems from amplifier
primary outputs to feed into another amplifier.
Figure 2 –ALIM 9706 Schematic
