15
Technical Description, con’t
Figure 24
Block Diagram
of the
Power Supply
POWER SAVE
CONTROL
CIRCUIT
BREAKER
POWER
RELAY
AC POWER
Figure 26
It is enclosed in the legendary McIntosh Potted Enclo-
sures and weighs 30 lbs. The six super size main filter
capacitors can store over 350 Joules of energy which
is necessary for the wide dynamic range that “Digital
Audio” demands. Refer to figure 26.
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 MC257 is equipped with
a circuit that provides remote Power Control from a
McIntosh A/V Control Center. When the A/V Control
Center is switched On, a (+5V) signal operates the
power relay in the MC257. The MC257 also has two
remote Power Control Out Jacks. The Power Control
signal from these jacks is delayed by a fraction 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 cir-
cuit breakers or blow fuses, a very important feature
in high power Home Systems employing multiple
MC257 Power Amplifiers.
