McIntosh MAC 4200 Owner's Manual page 17

POWER GUARD*
POWER GUARD* assures that the amplifier can not be
overdriven so amplifier output clipping is eliminated.
Clipping is caused when the amplifier is asked to produce
more power output than it can deliver with low distor-
tion. Amplifiers are capable of delivering large quantities
of power when they are driven to clipping and can have
more than 40% harmonic distortion. The extra energy con-
tent of the clipped signal will damage most speakers. A
Mclntosh advancement helps to protect your speaker
from this kind of damage. The POWER GUARD* circuit
compares the wave shape of the input signal with the out-
put signal. If the non-linearity between the two signals ex-
ceeds 0.5% the POWER GUARD* circuit operates.
BALANCE YOUR STEREO SYSTEM
The performance and enjoyment of a stereo system is
greatly increased when the sound is properly balanced.
The balance of the stereo system is affected by many
things including the phase relationship of the
loudspeakers, room acoustics, furniture placement, room
shape, small differences in loudspeakers etc.
TO ADJUST LOUDSPEAKER PHASE
Press the MONO pushbutton. Play a familar recording.
Turn the BALANCE control to 12 o'clock. Stand about ten
feet in front of and midway between the loudspeakers.
The sound should appear to come directly from in front
of you. If the sound is not directly in front of you, reverse
the leads on one of the loudspeakers only. When the
sound comes from the midpoint between the speakers
they are in phase.
TO BALANCE LOUDNESS
Press the MONO pushbutton. Turn the BALANCE control
to the 12 o'clock position. While the program is playing,
stand between the two loudspeakers. For any difference
in loudness between speakers, turn the BALANCE control
toward the speaker that is not as loud. Adjust until the
sound is equal in loudness from each speaker.
FRONT PANEL CONTROLS 15