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English --
Dead Zone on MUTE IN Defeat
As supplied, MUTE IN is intended for use as a momentary
cough button or privacy function (mute when necessary).
However, if the MUTE IN is intended to be used so that the talk-
er must unmute microphones to enable speech pickup (un-
mute when needed), this modification is needed. This re-
moves the muted channel from the MaxBus which eliminates
“dead zones.” A dead zone is an area in which a microphone
picks up a talker through a muted microphone and other micro-
phones do not activate for that talker.
Procedure:
Short jumper X115. Repeat these steps for all
channels needing modification.
Change MUTE IN to Inhibit
As supplied, a channel will mute when its MUTE IN termi-
nal is grounded. The mute function can be changed to “Inhibit”
by an internal modification for each channel. After the modifi-
cation, a logic “Low” at the MUTE IN terminal prevents that
channel from gating on if it is off, but allows it to remain on if it is
already on.
IMPORTANT:
To prevent high-frequency oscilla-
tion, never connect a channel’s GATE OUT to its own MUTE IN
unless the “Inhibit” modification has been made.
Procedure:
Short jumper X111. Repeat these steps for all
channels needing modification.
Change OVERRIDE IN to MUTE IN for Use with Fili-
buster Mode
This modification should only be performed with the
Change MUTE IN to Inhibit
modification described above.
Procedure:
Short jumper X113. Remove resistors R1046
and R1058. Repeat these steps for all channels needing modi-
fication.
Change Off-Attenuation Level
This modification changes the off-attenuation level from
-15 dB to a selected value. Select from the following resistor
values.
Off-Attenuation Level
Resistor Value
10 dB
18 k
W
20 dB
50 k
W
30 dB
150 k
W
Procedure:
Remove resistors R9088 and R9145. Install
new resistor at jumper points X904 and X908.
Increase Hold Time
In place of the DIP switch SW902 option of 1.0-second
hold time, the hold time can be increased to 1.5 seconds.
(More than 1.5 seconds is not recommended.)
Procedure:
Install a 470
k
W
resistor across jumper points
X902. Move DIP switch down to 1.0-second position.
Decrease Hold Time
The hold time can be decreased from the factory preset of
0.4 seconds to 0.3 seconds. (Less than 0.3 seconds is not rec-
ommended.)
Procedure:
Install a 2 M
W
resistor at jumpers X903.
Remote Control of Link Global/Local, Off-Attenua-
tion, Last Mic Lock-on, and Automatic/Manual DIP
Switches
If desired, these functions can each be remotely con-
trolled with an SPST switch.
Procedure:
1. Solder a wire in the pc board jumper hole adjacent to the
desired function (printed on the pc board). These jumpers
are located just behind DIP switch SW902.
2. Solder a wire in the pc board jumper hole marked “GND”
near switch SW902.
3. Set the desired DIP switch(es) to the Up position.
4. Run the jumper wires to the desired remote location and
solder them to an SPST toggle switch. The wires can exit
the AMS8100 chassis above the DIP switches. Shorting
any wire to the Ground wire will set the function(s) to the
corresponding switch “down” position.
Remote Volume Control of Channels
Using an external VCA (Voltage Controlled Amplifier), the
level of a channel, the aux, or the master can be remote con-
trolled via a DC voltage. An example of an external VCA is the
ST-VCA1 from Radio Design Labs. They can be reached by
phone at 1--800--281--2683, or on the Internet at
www.rdlnet.com.
For channel control — Perform
Direct Out to Post-Fader
Send/Return
modification. Connect the tip of a 1/4-in. connec-
tor to the line input of the VCA, and the sleeve to the ground of
the VCA. Connect the ring to the line output of the VCA. Plug
the 1/4-in. connector to the Direct Out jack of the AMS8100.
The channel’s level control should be set at 5.
For Aux In control — Connect the external source to the
VCA line input. Connect the VCA line output to the tip and
sleeve of the AMS8100 Aux input. The Aux control should be
set at 5.
For Master control — Connect AMS8100 Line output to
the VCA line input. Connect the VCA line output to the external
device (amplifier, tape recorder, etc.). Set Master control at 5.
Using Multiple Gates to Drive a Single Relay
When using muliple gates to drive a single relay, the relay
may fail to release when gate out changes state.
Procedure:
Using a soldering iron, remove two 30 k
W
resi-
sitors from the circuit path.
For example, if Gate Out #7 is in parallel with other Gate
Outs to drive one relay, remove resistors R9026 and R9027.
Or, if Gate Out #1 is in parallel to drive one relay, remove resis-
tors R9039 and R9041. Do the same for any Gate Out used in
parallel with any other gate out.
This modification should not be necessary if a relay is con-
trolled by only one Gate Out.
