Rear Panel Features
AC Power Inlet
The 3 pin IEC power inlet is located on the bottom left of the rear panel and accepts a standard mains power lead fitted
with an IEC connector. Before plugging in a power lead, please check the rear panel of the amplifier to ensure that the
voltage label shows the correct AC operating voltage for your part of the world.
The inlet is equipped with an in-built AC fuse holder fitted with a 4 Amp slow blow fuse plus a spare fuse. Please ensure
that the mains power cord is disconnected before attempting to check or replace this fuse. Power consumption is 300
VA (max).
Speaker Output Terminal Strip
Located on the top left of the rear panel is the speaker output terminal strip. Reading from left to right, the connections
are:
COM
Common or “-” for low impedance speaker loads (4 or 8 ohms).
4
The “+” for 4 ohm speaker loads (use with common)
8
The “+” for 8 ohm speaker loads (use with common)
COM
Common or “-” for 70v or 100v speaker loads (maximum load of 80 ohms at 100v)
70
The “+” for 70v line speaker loads (use with common)
100
The “+” for 100v line speaker loads (use with common)
Please ensure that the correct “Common” is used. Low impedance and 70/100v loads can be used simultaneously but
please pay careful attention to the overall speaker load. When used individually, the low impedance load should be 4
ohms or higher while the 100v line load should not fall below 80 ohms. When both outputs are used simultanously,
ensure that neither output is loaded to maximum.
24 Volt Power
Located on the rear panel are the red and black connection posts for 24v power. This feature can be used as either a back-
up facility (if mains power fails) or for applications where AC power is not available. The left side red post is the +
(positive) terminal while the right side black post is the - (negative) terminal. The DC current drain is 8 Amps maximum
at full power. This socket also provides trickle charge to a DC battery supply (if connected) when the DCM120 is
operated from AC mains power. The level of trickle charge is 300 mA, maximum.
Mains Failure: The LED glows red if there is a failure in the AC mains power supply. However, this LED will only glow
if there is a DC supply voltage present. If no DC supply voltage is present then this LED will not glow.
Output Level VU Meter: A 10 segment LED VU meter is provided to give an indication of the output signal level of the
amplifier from -25 to +3 dB. During normal operation, the LED’s will oscillate with changes in the program signal. Care
should be taken to avoid more than occasional illumination of the red LED’s. If the LED’s in the red zone are lit
continually, then the output level control (or the level of the input signal to the DCM120) should be adjusted to reduce
the output level. Too much output level can cause distortion, activate the internal limiter or possibly damage the
connected speaker system.
2 30 V
2 40 V
C
C
4
1 00
8
O H M
VO LT
7 0
AC FU S E 4 A S /B
EN GI N EE R ED BY AUD I O T ELE X C O M M U N IC AT IO N S PT Y LTD SYDN EY AU S TR ALIA
D C F US E
1 0A S /B
2 4 VD C
IN PU T
