McIntosh MI254 Owner's Manual page 10

Output Terminals
When connecting the Loudspeaker Hookup Cables to
the MI254 Amplifier Output Terminals please follow
the steps below:
1. Rotate the top of the Output Terminal Post coun-
terclockwise until an opening
appears. Refer to figures A and
B.
2. Insert the Loudspeaker hookup
cable into the Output Terminal
Post opening or the cable spade
lug around the center post of
the Output Terminal. Refer to
figure C.
3. Rotate the top of the Output
Terminal Post clockwise until it
is finger tight. Refer to figure D.
4. Place the supplied McIntosh
Wrench over the top of the Out-
put Terminal and rotate it one
quarter of a turn (90°) to secure
the Loudspeaker Cable Connec-
tion. Do not over tighten. Refer
to figure E.
How to Connect Different Sources for
Zones B and C System
Caution: Do not connect the AC Power Cord to the MI254
Rear Panel until after the Loudspeaker Connec-
tions are made and the protective Terminal Con-
nections Cover is installed. Failure to observe
this could result in Electric Shock.
The connection instructions below, together with the
MI254 Connection Diagram located on the separate
folded sheet "Mc1B", is an example of Different
Sources for a Zone B and Zone C System. Your sys-
tem may vary from this, however the actual compo-
10
nents would be connected in a similar manner. For
additional information refer to "Connector and Cable
Information" on page 3.
1. The Power Control Connection between the MI254
and a Multi Zone A/V Control Center provides
automatic Power Control of the MI254. The inter-
nal settings of the A/V Control Center can provide
the Power Control Function so the MI254 will be
switched On when either Zone B, Zone C or both
Opening
Zones are active. Connect a Power Control Cable
Figure B
Figure A
from the A/V Control Center TRIG 2 jack to the
MI254 PWR CNTRL IN Jack.
Note: The AUTO OFF Signal Sensing Circuitry
2. Connect unbalanced cables from the A/V Control
Figure C Figure D
Center Analog Audio Out Zone 2 (Left and Right
Channel) to the MI254 BUS 1 INPUTS, making
sure to match up channel designations.
3. Connect unbalanced cables from the A/V Control
Center Analog Audio Out Zone 3 (Left and Right
Figure E
Channel) to the MI254 BUS 2 INPUTS, making
sure to match up channel designations.
4. Place the CHANNEL 1/R and 2/L Input Selector
Switches to the "-1" Position.
5. Place the CHANNEL 3/R and 4/L Input Selector
Switches to the "-2" Position.
This McIntosh MI254 Power Amplifier is designed
for Loudspeakers with an impedance of 4 ohms or
8 ohms. Connect a single Loudspeaker only to each
Channel Output Terminals.
When connecting Loudspeakers to the MI254 it
is very important to use cables of adequate size, so
there is little to no power loss in the cables. The size is
specified in Gauge Numbers or AWG (American Wire
is automatically activated when there is no
Power Control Cable connected to the MI254
and only Zone C is being used.
Gauge). The smaller the Gauge number, the larger the
wire size:
Loudspeaker Cable Distance vs Wire Gauge Guide
25 feet 50 feet
Loudspeaker
(7.62 meters) (15.24 meters)
Impedance
or less or less
4 Ohms 14AWG 12AWG
8 Ohms 16AWG 14AWG
6. Prepare the Loudspeaker Hookup Cable for attach-
ment to the MI254 Power Amplifier:
Bare wire cable ends:
Carefully remove sufficient insulation from
the cable ends, refer to figures 1, 2 & 3.
If the cable
is stranded,
carefully
twist the
Figure 1
strands to-
gether as tightly as possible.
Notes: 1. If desired, the twisted ends can be tinned
with solder to keep the strands together.
2. The prepared bare wire cable ends may be
inserted into spade lug connectors.
3. Banana plugs are for use in the United
States and Canada only.
Banana Plugs are for use in the United States and
Canada only:
7. Attach the previously prepared bare
wire cable ends into the banana plugs
and secure the connections. Refer to
figure 4.
8. Referring to figure 5, connect the
Loudspeaker hookup cables with
banana plugs into the hole at the end
of the MI254 Negative and Positive
Output Terminals, making sure to
100 feet
(30.48 meters)
or less
10AWG
12AWG
Figure 2 Figure 3
Figure 4
Figure 5