8
Rear Panel Connections and Switches
1� Input Mode
To select the BALANCED or UNBALANCED
connection, use the INPUT MODE switch
to toggle between these two options. Each
input section can accept a male balanced XLR
cable or a male unbalanced RCA cable. All
inputs must use the same type of connection
(BALANCED or UNBALANCED). Refer to
page 5,
Connector Information
.
2�
Amplifier Mode
MONO is the common choice for most
applications of the MC451. The signal from
a single preamplifier will be sent to both the
solid state and vacuum tube amplifiers with the
frequency range tailored by the crossover to
match the attached loudspeaker.
SEPARATE
can be useful for situations where
an external crossover is used. SEPARATE can
also be used for feeding full-range signals to
two separate loudspeakers from a single MC451.
Note: If you need to switch the INPUT or AMPLIFIER
MODE, it is best to do so when the MC451 is
powered off to avoid any unpleasant noise from the
loudspeakers.
3� Vacuum Tube Input
With the
AMPLIFIER MODE
switch set to
MONO, the input is disabled.
With the
AMPLIFIER MODE
switch set to
SEPARATE
, this input sends a full range input
signal to the vacuum tube amplifier.
4� Mono / Solid State Input
With the
AMPLIFIER MODE
switch set to
MONO, the input signal is sent to the internal
crossover. The crossover then sends signals to
each amplifier section based on the crossover
settings.
With the
AMPLIFIER MODE
switch set to
SEPARATE
, this input sends a full range input
signal to the solid state amplifier.
5� Crossover
Refer to page 12,
Setting Up the Crossover
for
additional information.
6� Power Control
Power control allows the MC451 to send and
receive control signals when connected to other
McIntosh products. In this way, powering on
or powering off a single component can do the
same for multiple units.
POWER CONTROL IN accepts an On/Off
signal from +5 to +12 volts. Meter and tube
lights can be controlled as well.
POWER CONTROL OUT will provide a +12
volt signal with a total current up to 25 mA.
Connections are made using an 1/8 inch stereo
mini phone plug. Refer to page 5,
Connector
Information
.
7�
Auto Off Function
The MC451 incorporates power saving circuitry
to automatically activate the power saving
standby mode. The MC451 will turn off after
approximately 30 minutes of no audio signal in
both amplifiers when the AUTO OFF switch is
set to ENABLED.
If the AUTO OFF switch is set to DISABLED,
the MC451 will remain on regardless of the
presence of any audio signal.
When there is a power control connection
between the MC451 and a preamplifier or source
component, the AUTO OFF function is disabled
regardless of switch position.
8� Vacuum Tube Outputs
Refer to page 5,
Connecting a Loudspeaker
for additional information.
9� Solid State Outputs
Refer to page 5,
Connecting a Loudspeaker
for additional information.
10� AC Input
Connect the MC451 power cord to a live AC
outlet. Refer to the rear panel for voltage and
current requirements.
11� Fuse
Under normal operating conditions the fuse
should not need to be replaced. If required, refer
to the rear panel for proper fuse type.
Содержание MC451
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