Controls and Features:
MOD 1 Front Panel
Power Switch:
Turns modulator power on/off.
Power Indicator:
Green LED indicates power on.
Audio Level Indicators:
“Ok” amber LED indicates proper audio input level.
“Hi” red LED indicates excessive audio input level.
Audio Level Control:
Screwdriver rotary adjustment for audio input level.
Infrared Test LED:
Infrared LED provides a modulated IR signal for
receiver testing, monitoring, audio source testing.
Tape Output:
RCA Jack provides unbalanced, line-level audio
output signal for tape recorders, etc.
MOD 1 Rear Panel
Balanced Microphone-Level Input:
Female XLR jack for use with low impedance (150 -
200
½
) microphones. Supplies simplex DC power
per DIN 45596 for condenser microphones.
Balanced Line-Level Input:
Female XLR jack for balanced, line-level inputs.
Can also accept unbalanced input, and 4
W
, 8
W
, or
16
W
speaker line.
70V (Hi-Level) Input:
Female XLR jack for direct connection to a 70V or
25V speaker line.
Input Level Switch:
Three-position switch selects mic-level, line-level, or
70V input for the XLR input jack.
Unbalanced Audio Inputs:
Two RCA jacks for unbalanced line-level audio
inputs. Inputs are mixed internally with the balanced
input signal.
High-Pass Filter:
Three position switch provides 6dB/octave low-
frequency roll-off to reduce noise, improve speech
intelligibility, compensate for typical high-frequency
hearing loss.
Modulator Outputs:
Two F-type connectors provide 95 kHz frequency
modulated outputs to feed two TX3 Transmitters.
Power Input:
Two-screw terminals for low-voltage power supply,
24VAC, 50 or 60Hz, 2.4VA.
Audio Input
Balanced
Line
Mic
70V
Model WIR MOD1 Infrared System Modulator
Input Level
Audio Inputs
Unbalanced
Left
Right
Hi-Pass Filter
20 Hz
175 Hz
725 Hz
6dB/octave
Modulator
Out
Modulator
Out
Power: 24 VAC, 60 Hz, 50VA
75 Ohm
75 Ohm
Made in USA
Williams Sound Corp.
Power: 24 VAC,
50-60 Hz, 10VA
Plug
Tape
Out
Infrared
Test Out
Audio Level
Hi
Ok
Power
MOD 1 Infrared System Modulator
Adjust
Williams Sound
+
-
0
I
Fig. 2: MOD 1 Front & Rear Panels
Williams Sound
®
Helping People Hear
5
