McIntosh MC 2500, Owner'S Manual

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Rear Panel Information
INPUT JACKS
In the stereo mode of operation, both input jacks
accept signal. In the mono mode of operation only
the Right (MONO) channel input jack accepts signal
and the Left channel input jack is disconnected.
INPUT LEVEL
The input sensitivity of the MC 2500 is 0.75 volts or
2.5 V depending on the position of the INPUT LEVEL
switch. With indicated voltage applied, the amplifier
will deliver its rated power. All Mclntosh preampli-
fiers have been designed to deliver 2.5 volts output
with rated input. For the best signal to noise ratio
when using Mclntosh source equipment, always
have the INPUT LEVEL switch in the 2.5 V position
and the front panel LEFT and RIGHT/MONO GAIN
controls in the fully clockwise position. If more gain
is desired the 0.75 V position may be used. For
source equipment other than Mclntosh, set the
switch in the position nearest to the stated output
rating of the source equipment.
MODE SWITCH
The MC 2500 will operate in three modes, Stereo,
Mono Bridge, and Mono Parallel. The Mono modes
differ in the loads they will drive and the connection
sequence to the speaker terminals. A connection
chart appears on the rear panel.
LEFT and RIGHT OUTPUT TERMINALS
For stereo operation, output impedances of 1, 2, 4
and 8 ohms have been provided on a secure, screw
type barrier strip. For monophonic operation, proper
interconnection provides 0.5, 1, 2, 4, 8, and 16 ohms
from the same barrier strips. See page 3 for connec-
ting instructions.
FANS SWITCH
Amplifier cooling is accomplished by means of
two low noise fans at the rear of the amplifier. Fan
operation is controlled by the three position FANS
switch. In the THERMALLY SWITCHED LO position
the fans do not operate when the amplifier is cool,
as when the amplifier is first turned on. As heat
develops, one or both fans will automatically turn on
to low speed operation as conditions require. Opera-
tion in this position of the switch produces the
lowest fan noise. Adequate cooling will be provided
for all normal operating conditions.
The THERMALLY SWITCHED HI switch position
functions like the LO position but the fans operate at
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