7
Connections on the Back
Your McIntosh Dealer is an expert in setting up
systems. Proper setup is important to get the most out
of your equipment. Consider using their services when
installing your MC901.
AC Power
This is the last of the connections to make. All other
connections should be made before connecting to
AC Power.
When all other connections are securely made, use
the supplied AC Power Cord to connect to a live AC
Outlet.
Input Mode
The MC901 will accept Balanced and Unbalanced
connections, but only one type of connection will
be recognized at a time. To select the Balanced or
Unbalanced connection, use the INPUT MODE
Switch to toggle between these two options.
If possible, use Balanced connections. The MC901
is a Quad Balanced Amplifier, so it can take
full advantage of the three conductors used in a
Balanced cable. An Unbalanced cable, which uses
two conductors, is more susceptible to noise.
If you need to switch the INPUT MODE, it is best
to do so when the MC901 is powered off to avoid
any unpleasant pop caused by switching the cable
source.
Input Select Switch
For both the Solid State and Vacuum Tube sections
of the MC901, it is possible to use the COMPOSITE
INPUT or a DIRECT INPUT. With the selection
of DIRECT INPUT, the signal bypasses the level
adjust and filter for that input.
The VACUUM TUBE INPUT SELECT is located
below the VACUUM TUBE DIRECT INPUT.
Select either DIRECT or COMPOSITE. With the
COMPOSITE INPUT selection, the signal will
flow through the Level Adjust and High Pass Filter.
(See “Setting the Filters” on page 12.) DIRECT
INPUT will not be affected by the settings for the
Level Adjust and High Pass Filter.
The SOLID STATE INPUT SELECT is located
below the SOLID STATE DIRECT INPUT.
Select either DIRECT or COMPOSITE. With the
COMPOSITE INPUT selection, signal will flow
through the Level Adjust and the Low Pass Filter.
(See “Setting the Filters” on page 12.) DIRECT
INPUT will not be affected by the settings for the
Level Adjust and the Low Pass Filter.
Selecting COMPOSITE, the signal from the
COMPOSITE INPUT is used. Selecting DIRECT
will use the signal from the corresponding DIRECT
INPUT.
Balanced and Unbalanced Inputs
There are three Input sections:
• VACUUM TUBE DIRECT INPUT
• COMPOSITE INPUT
• SOLID STATE DIRECT INPUT
Each Input section can accept a male Balanced XLR
cable or an Unbalanced cable with a male RCA
Phono plug. Balanced XLR is the recommended
method for sending input to the MC901, especially
with longer runs. All inputs must use the same type
of connection (Balanced or Unbalanced).
The Pin configuration of the XLR jacks are:
Figure 05–
+
Input
Ground
-
Input
XLR Pin Configuration
Typically, an input of the MC901 will be connected
to an Output of a Preamplifier.
Composite or Direct Inputs
Composite Input is the common choice for most
applications of the MC901. 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 filters to match the attached
Loudspeaker.
The Direct Inputs can be useful for situations with
external crossover settings feeding the MC901.
Direct Inputs can be used for feeding full-range
signals to two separate Loudspeakers from a single
MC901. Some people have different setups for
different genres of music. For instance, Classical
Music might be played through a dedicated Tube
setup, while Rock Music may be through a Solid
State system.
In the case of wanting the MC901 to power two
separate Loudspeakers, the DIRECT INPUTs should
