McIntosh MC 7270, Owner'S Manual

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METERS
Output power monitor meters calibrated in both watts
and decibels, indicate the output power of each channel.
The upper scale on the meter has been calibrated to
show average watts and the lower scale, decibels.
Reading from right to left, the marks between the
numbers indicating watts are (from the indicated 270
watts): first mark, 108 watts. Second 54 watts, the in-
dicated 27 watts, 10.8 watts, 5.4 watts, the indicated 2.7
watts, 1.08 watts, 0.54 watts, the indicated 0.027 watts,
0.0108 watts, .0054 watts, the indicated 0.0027 watts,
0.00108 watts and 0.00054 watts.
The meters respond to the peak output of each channel.
Ordinary meters lack the capability of indicating the short
interval information in a sound wave. The mass of the
meter movement is too great to respond to the nearly in-
stantaneous changes in music program material. Short in-
terval information can have a duration as short as half a
thousandth of a second. Ordinarily, a meter pointer mov-
ing over its scale in such a short time could not be seen.
Mclntosh has developed circuits that drive the meters to
respond to the short interval information in a sound wave
to an accuracy of 90%. The electrical pulse that drives the
meter pointer is time stretched so that the peak position
of the pointer can register in the persistence of vision
characteristic of the retina of the human eye. The pointer
can be locked at the peak indication by switching to the
HOLD position of the METER range switch.
LEFT CAIN
Use the LEFT GAIN control to adjust the output in the
left channel to the desired listening level. Turn the control
clockwise to increase the output.
RIGHT/MONO GAIN
Use the RIGHT/MONO GAIN control to adjust the out-
put in the right channel to the desired listening level. Turn
the control clockwise to increase the output.
When connected for monophonic operation use the
RIGHT/MONO GAIN to adjust the total output to the
desired listening level. The rear panel MODE SWITCH
must be in the MONO-BRIDGE position.
10 FRONT PANEL CONTROLS