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 250 watts (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
Positive “+” for 4 ohm speaker loads (use with common)
8
Positive “+” 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
Positive “+” for 70v line speaker loads (use with common)
100
Positive “+” 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 simultaneously,
ensure that neither output is loaded to maximum.
VOX Relay Output
The terminal strip to the immediate right of the AC inlet features a relay output. This relay is activated when signal is
present on any of the priority inputs. This would normally be inputs 1, 2 and 3 however some or all of these channels can
be removed from the priority bus via internal links (see “Muting” further on in this manual). The unit is shipped from the
factory with inputs 1, 2 and 3 having priority so assuming that this has not been changed, then signal from any of these
inputs will activate the VOX relay circuit. The relay outputs are C (Common), NO (Normally Open) and NC (Normally
Closed). The NO or NC selection provides the installer with the option of the relay either opening or closing a contact.
This feature is normally used in conjunction with relay override attenuators (volume controls). In this application, the
relay output could trigger a power supply which in turn bypasses the remote attenuators. The result is that priority inputs
will always be heard irrespective of the attenuator setting. The relay contacts are 0.5 amps at 100VAC.
Signal LED
The green “Signal” LED located next to the On LED indicates that the ACM120XL is passing audio. The signal LED
is a simple method to trouble-shoot installations especially in multi-amplifier projects.
Rack Mounting
The ACM120XL is supplied with rack ears attached to allow mounting within a standard 19” equipment rack. As is the
case with almost all audio products, adequate ventilation and air flow is required. When installing multiple ACM
amplifiers within the one rack, it is recommended that at least 1 rack unit of ventilation space is left between every two
amplifiers.
For table or shelf mounting, the rack ears can be removed using a screwdriver. Once the rack ears are removed, please
reinstall the screws.
