McIntosh MC 2250, Руководство пользователя

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How to Connect
INPUT CONNECTIONS
STEREO OPERATION
Use shielded cables to connect the signal from
the preamplifier or signal source to the power
amplifier. To minimize the possibilty of hum the
shielded cables should be run parallel to each other
or loosely twisted together. Locate the cables away
from speaker leads and AC power cords. All connec-
tions are made on the back panel of the MC 2250.
For stereo operation, the left output of the
preamplifier should be plugged into the Left INPUT
jack of the power amplifier. The right output of the
preamplifier s h o u l d be plugged into the
Right/MONO INPUT jack of the power amplifier.
In stereo operation the MODE SWITCH must be in
the STEREO position.
MONOPHONIC OPERATION
For monophonic operation the MODE switch on
the back panel of the MC 2250 must be placed in one
of the MONO positions. For the proper choice, see
the section on monophonic output connections.
Connect a shielded cable from the signal source to
the Right/MONO INPUT jack of the MC 2250. The
Left INPUT is not used.
Be certain that the MC 2250 is never operated in
the stereo mode with the outputs connected for
monophonic operation. Should the MODE SWITCH
be left in the STEREO position and the outputs re-
main strapped for a mono parallel load, one
amplifier channel will attempt to drive the other
which causes high circulating currents and
overheating.
OUTPUT CONNECTIONS
Be certain the loudspeakers connected to the MC
2250 are capable of handling the power output of the
amplifier.
Selection of the proper gauge wire to connect the
loudspeakers to the amplifier preserves the quality
of sound reproduction for which the loudspeakers
have been designed. If undersize wire is used,
resistance is added to the amplifier/loudspeaker
combination which adversely affects the perfor-
mance. Added resistance causes depreciation of
damping characteristics, modification of frequency
response and reduction in power to the loudspeaker.
Use lamp cord or wire with similar insulation to
connect the speakers to the amplifier. In all cases,
the leads to and from the speaker should be twin
parallel conductor or twisted pair. When using 8
ohm speakers and for the normally short distances
of under 30 feet between the amplifier and speaker,
#18 wire or larger can be used. For distances over 30
feet a larger diameter wire is required. Select the
correct size from the chart below. The DC resistance
of the speaker leads should be less than 5% of the
speaker impedance. Resistance of the leads must
be computed for the length of wire both to and from
the speaker or speakers.
MAXIMUM WIRE LENGTHS
Wire
Gauge
18
16
14
12
10
For 4 Ohm Load
Feet
15
25
40
60
100
Meters
4.57
7.62
12.19
18.29
30.48
For 8 Ohm Load
Feet
30
50
80
120
200
Meters
9.14
15.24
24.38
36.58
60.96
Wire lengths above represent the wire resistance
equal to 5% of the speaker impedance.
For multiple speaker operation, run separate
leads from the amplifier to the speakers.
STEREO OPERATION
First check the impedance of the speaker to be
connected. This is usually found on the speaker
system near the terminals or in the speaker litera-
ture. The proper terminals on the MC 2250 can then
be used. Connect the + or rated impedance ter-
minal of the left speaker to the corresponding LEFT
OUTPUT terminal on the amplifier. Connect the - or
the common terminal of the left speaker to the left
COMMON output terminal of the amplifier. In the
same way connect the right speaker to the amplifier
RIGHT OUTPUT terminals.
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