17
Control Center is switched On, a (+5V) signal oper
-
ates the power relay in the MC302. The MC302 also
has two remote Power Control Out Jacks. The Power
Control signal from these jacks are delayed by a frac-
tion of a second so that the turn on power surge of the
next power amplifier occurs at a later time. This helps
prevent power circuit overload that could trip circuit
breakers or blow fuses, a very important feature in
a high power Home Systems employing multiple
MC302 Power Amplifiers.
Guard circuit acts so fast
that there are absolutely
no audible side effects
and the sonic purity of
the music reproduction is
perfectly preserved. The
MC302 Power Amplifier
with Power Guard is not
limited to just the rated
power output, but will
actually produce distor-
tion free output well
above its rated power due
to the McIntosh philosophy of conservative design.
Power Supply Circuits
To compliment the design of the MC302 Power Am-
plifier Circuitry, there is a high current high voltage
power supply for both channels. Refer to figures 22
and 25. The very large Power Transfomer can supply
over 13 amps of continuous current. Refer to figure 23
(golf ball is for size comparison).
It is enclosed in the legendary McIntosh Potted Enclo-
sures and weighs 28lbs. The two super size main filter
capacitors can store over 140 Joules of energy for both
amplifier channels, necessary for the wide dynamic
range that “Digital Audio” demands. Refer to figure
24.
The power
amplifier
draws high
current
from the AC
power line.
Therefore, it
is important
that they
plug directly
into the wall
outlet.
Also, most
owners desire one power switch for the whole audio
system. The MC302 is equipped with a circuit that
provides remote Power Control from a McIntosh A/V
Control Center. Refer to figure 25. When the A/V
Figure 21
With Power Guard
Technical Description, con’t
Figure 22
Block Diagram
of the
Power Supply
INRUSH
CURRENT
LIMITER
AC Power
MAIN RELAYS
BACKUP
POWER SUPPLY
CONTROL
LOGIC
LIGHTING
CONTROL
POWER
CONTROL
Figure 23
Figure 24
Figure 25
