McIntosh MA 5100, Руководство пользователя

Страница: 6 / 20

POWER AMPLIFIER SECTION
There are 9 transistors in each power amplifier. The input stage is
a pair of matched transistors arranged as an emitter coupled amplifier
with two inputs and one output. The program from the preamplifier
connects to one of the inputs, the second input is fed from the feed-
back loop that is around the power amplifier section. Both AC and DC
feedback are used around the power amplifier section. Noise and dis-
tortion are reduced by the use of a large quantity of feedback.
The power transistors are mounted on oversized anodized heat sinks.
The heat sinks assure that under normal operation the transistors will
operate at a low temperature. If temperatures increase due to shorted
speaker, or restricted ventilation, an automatic temperature sensing
device turns off the MA5100. The device operates automatically at a
preset temperature. The MA 5100 will turn on again when the tempera-
ture has decreased to normal operation. This additional feature gives
your MA5100 complete reliability under the most extreme operating
conditions.
To further insure reliability a special power output SENTRY MONITOR-
ING CIRCUIT prevents failure of the power output transistors due to
abnormal mismatch of the output. When your MA5100 operates nor-
mally the SENTRY MONITORING CIRCUIT has no effect on signals
passing through the power amplifier. If the power dissipation should
rise above normal operation, the SENTRY MONITORING CIRCUIT re-
stricts the drive to the output transistors. The action of the SENTRY
MONITORING CIRCUIT is immediate for any input signal or load
combination. This arrangement assures complete circuit reliability.
Only Mclntosh gives you this degree of protection.
POWER SUPPLY SECTION
There are four separate power supply sections. One positive and one
negative high current supply is used for the output stages. One positive
and one negative low current supply is used for the preamplifier and
power amplifier input stages. All supplies are full wave and use silicon
rectifiers. Adequate filtering is used to assure an absolute minimum of
output hum. The power output stage filter capacitors have very high
capacity, which allows full power output below 20 Hz. The power trans-
former is generous in size and runs cool, even under heavy use.
MA 5100
4