17
Technical Description, con’t
Figure 24
Block Diagram
of the
Power Supply
INRUSH
CURRENT
LIMITER
AC Power
MAIN RELAYS
BACKUP
POWER SUPPLY
CONTROL
LOGIC
LIGHTING
CONTROL
POWER
CONTROL
Power Supply Circuits
To compliment the design of the MC152 Power Am-
plifier Circuitry, there is a high current high voltage
power supply. Refer to figures 24 and 26. The very
large Power Transfomer can supply over 6 amps of
current. Refer to figure 25 (golf ball is for size com-
parsion). It is enclosed in the legendary McIntosh Pot
-
ted Enclosures and weighs 18 lbs.
There are two super size main filter capacitors sup-
pling all of the 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 MC152 is equipped with a
circuit that provides remote Power Control from a Mc-
Intosh A/V Control Center. Refer to figure 14 on page
14. When the A/V Control Center is switched On, a
(5-12V) signal operates the power relay in the MC152.
The MC152 also has a Power Control Out Jack. The
Power Control signal from the jack 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 circuit breakers or blow fuses, a very important
feature in a high power Home Systems employing
multiple MC152 Power Amplifiers.
Figure 26
Figure 25
