3
XLR Connectors
Below is the Pin configuration for the XLR Balanced
Input, Input/Output Connectors on the MC1.25KW.
Refer to the diagram for connection:
PIN 1: Shield/Ground
PIN 2: + Input/Output
PIN 3: - Input/Output
Power Control Connector
The MC1.25KW Power Control Input (Trigger Con-
trol) receives an On/Off signal from +5 to +12 volts.
The Power Control Output
will in turn provide a +12 volt
Output Signal with a total cur-
rent up to 50mA. An additional
connection is for controlling the
illumination of the McIntosh
Power Output Meters. The 3.5mm stereo mini phone
plug connects to another McIntosh Power Amplifier.
Output Terminal Connector
When cables with spade lugs are used
for Loudspeaker Connection, the spade
lugs need an opening of at least 3/10 inch
(7.6mm)
5. The MC1.25KW incorporates the very latest in
Fully Double Balanced Circuitry. As a result, the
Loudspeaker Negative Connections are above
chassis ground. Do not combine any connections
together, ground them or connect with another
MC1.25KW.
6
.
In the event the MC1.25KW over heats, due to im-
proper ventilation and/or high ambient temperature,
the protection circuits will activate. The Front Panel
Power Guard LED will continuously indicate ON
and the audio will be muted. When the MC1.25KW
has returned to a safe operating temperature, nor-
mal operation will resume.
7. When discarding the unit, comply with local rules
or regulations. Batteries should never be
thrown away or incinerated but disposed
of in accordance with the local regulations
concerning battery disposal.
8. For additional information on the MC1.25KW and
other McIntosh Products please visit the McIntosh
Web Site at www.mcintoshlabs.com.
Caution: The MC1.25KW Amplifier weight is 158 pounds
(71.7 kilograms). It requires two or more per-
sons to safely handle when moving the ampli-
fier.
1. For additional connection information, refer to the
owner’s manual(s) for any component(s) connected
to the MC1.25KW.
2. The MC1.25KW mutes the speaker output for ap-
proximately two seconds when first turned on.
3. For the best performance and safety it is important
to always match the impedance of the Loudspeaker
to the Power Amplifier connections. Refer to “How
to Connect” pages 8 thru 11.
Note: The impedance of a Loudspeaker actually var-
ies as the Loudspeaker reproduces different
frequencies. As a result, the nominal impedance
rating of the Loudspeaker (usually measured at
a midrange frequency) might not always agree
with the impedance of the Loudspeaker at low
frequencies where the greatest amount of power
is required. Contact the Loudspeaker Manufac-
turer for additional information about the actual
impedance of the Loudspeaker before connecting
it to the McIntosh MC1.25KW.
4. It is very important that loudspeaker cables of ad-
equate size be used, so that there will be no power
loss. The size is specified in Gauge Numbers or
AWG, (American Wire Gauge). The smaller the
Gauge number, the larger the wire size:
If your loudspeaker cables are 50 feet (38.1m) or less,
use at least 14 Gauge.
If your loudspeaker cables are 100 feet (76.2m) or
less, use at least 12 Gauge.
General Information
Connector and Cable Information
Trigger
Control
Ground
Meter
Illumination
Control
PIN 1
PIN 2
PIN 3
PIN 2
PIN 1
PIN 3
OUT
IN
3/10 of an inch
(7.6millimeters)
General Information and Cable Information
