5
Connector Information
XLR Connectors
When connecting loudspeaker cables to the
MC451 output terminals follow the steps below:
1� Make sure AC power is disconnected�
2. Rotate the top of the output terminal counter-
clockwise until an opening appears.
Opening
Loudspeaker Connections
The MC451 is designed for two separate connec-
tions to a single loudspeaker. The solid state
amplifier output terminals should be connected to
the low frequency terminals of your loudspeaker.
The vacuum tube amplifier should be connected to
the mid/high terminals of your loudspeaker.
Any
jumpers between the low and mid/high terminals
on the loudspeaker must be removed�
Refer to the
Connection Diagram
on pages 10-11 for additional
information.
Loudspeaker Impedance
Each amplifier has a 2 ohm, 4 ohm, 8 ohm and
COM output terminal. Based on the specifications
of your loudspeaker, determine the best impedance
to use for each connection. It is a safe bet to use
the lower impedance output terminals for a speaker
whose impedance falls between two choices.
Loudspeaker Cables
When connecting loudspeakers to the MC451 it is
very important to use cables of adequate size. The
size is specified in AWG (American Wire Gauge).
The smaller the gauge number, the larger the wire
size.
Loudspeaker Cable Wire Gauge Guide
Loudspeaker
Impedance
Cable Distance
25 feet
(7.62 meters)
or less
50 feet
(15.24 meters)
or less
100 feet
(30.48 meters)
or less
2 ohms
12AWG
10AWG
8AWG
4 ohms
14AWG
12AWG
10AWG
8 ohms
16AWG
14AWG
12AWG
Connecting a Loudspeaker
3. Insert the loudspeaker cable into the output
terminal.
Proper polarity must be
maintained for all connections� (+/-)
4. Rotate the top of the output terminal clock-
wise until it is finger tight.
5.
Place the McIntosh wrench over the top of the
output terminal and rotate it one quarter of a
turn (90°).
Do not over tighten�
Meter/Tube
Illumination
Control
Power
Control
Ground
Signal
Ground
RCA Connectors
Power Control Connectors
Output Terminals
PIN 1
PIN 2
PIN 3
(+) Signal
Ground
(-) Signal
2
1
3
3/10 in
7.6 mm
11
/
64
in
4.4 mm
Ø
