McIntosh MC1201 - Manual (Page 14)

14
Figure 16
Input Test Signal
The special Balanced Dual Core Autoformer creates an
ideal match between the power amplifier output stage and
the loudspeaker. A McIntosh amplifier with an Autoformer
can be used to safely drive multiple speakers without re-
ducing the life expectancy of the power amplifier. Refer to
figure 13.
There is absolutely no performance limitation with an
Autoformer. Its frequency response exceeds that of the out-
put circuit itself, and extends well beyond the audible
range. Its distortion level is so low it is virtually impossible
to measure.
In the rare event of a power amplifier output circuit fail-
ure, the McIntosh Autoformer provides absolute protection
from possible damage to your valuable loudspeakers. The
unequaled expertise of McIntosh in the design and manu-
facturing of Autoformers is legendary in the high fidelity
industry. McIntosh engineers know how to do it right.
Power Output Meter
The McIntosh MC1201 has a huge hand built Output Watt
Meter that responds 95% full scale to a single cycle tone
burst at 2kHz. Refer to figure 14. Voltage and current out-
put are electronically measured, multiplied and fed to a
special circuit that accelerates the pointer movement in the
upward direction. When the pointer reaches its peak it
pauses only long enough for the human eye to perceive its
position, then drops. It is almost 10 times faster than a pro-
fessional VU meter.
A front panel switch is provided to change the meter to
the Watts Hold Mode of operation. This allows fast upward
movement of the pointer but greatly increases Hold Time at
the peak of its travel. The highest power output of the
source material is thus recorded.
Protection Circuits
The MC1201 incorporates a version of the McIntosh Sen-
try Monitor Output Transistor Protection Circuit. Refer to
Figure 15. There is absolutely no compromise in sonic per-
formance with this
circuit, and it en-
sures safe opera-
tion of the ampli-
fier under even the
most extreme oper-
ating conditions.
The different types
of protection cir-
cuits incorporated
in the MC1201 in-
sure a long and
safe operating life.
This is just one of
the many characteristics of McIntosh Power Amplifiers
that make them world famous.
The MC1201 also includes the unique patented McIn-
tosh Power Guard circuit.
Power Guard eliminates
the possibility of ever
overdriving the amplifier
into clipping. Refer to
figures 16, 17 and 18. An
overdriven amplifier can
produce both audible and
inaudible distortion levels
exceeding 40%. The au-
dible distortion is un-
pleasant to hear, but the
inaudible ultrasonic dis-
tortion is also undesir-
Figure 14
Figure 13
Figure 15