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MC73OO
Power Amplifier
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The Mclntosh "Always In Style"
TIMELESS LOOKS
PEAK PERFORMANCE
OPTIMUM DEPENDABILITY
CLASSIC DESIGN
The classic appearance of a Mclntosh amplifier
complements any home decorative scheme. Each
component is selected for durability, as well as
aesthetics.
Consider the construction and materials used in
the front panel and knobs. Reverse silk-screened
with thermal setting epoxy screen inks, the glass
panels are meticulously hand inspected and are
free from bubbles, flow marks and other faults.
Anodizing, an electro-chemical process that leaves
a color dyed and hardened surface impervious to
attack from common household cleaning fluids,
oils and acids from the skin, is used on the panel
frame and aluminum knobs to maximize their
resistance to wear.
This handsome combination of glass, anodized
aluminum, and thermal setting epoxy inks requires
very little maintenance to keep the MC7300 looking brand new. Its subtle yet sophisticated styling
will
remain
in
good
taste
throughout
the
years.
(safe operating area). The power transistor
characteristics, the power supply voltage used, and
the output autoformer ratio have been matched for
high efficiency, maximum power output with low
distortion, and reliable long life operation.
Versatile Mclntosh Power Amplifiers
Deliver Full Power — Always
The Mclntosh output circuit, superior in its performance, demands a superior method of coupling
the amplifier output to the loudspeaker load. A
Mclntosh designed and manufactured
autotransformer ensures peak performance and
protection, as well as outstanding compatibility
between amplifier and speaker.
The Mclntosh autotransformer offers these benefits:
• Transistors, used in amplifier output circuits, are
designed to work into an optimum low impedance load. Variations in frequency, or the use
of multiple speakers (which modify the impedance as seen by the output of the amplifier),
often compromise an amplifier's performance.
The Mclntosh autotransformer prevents these
variables from causing restricted performance,
output transistor heating, and/or circuit failure.
Rear view
Mclntosh Quality Begins With Careful
Design For Cool Operation
An
amplifier's
per ventilation for cool operation. In fact, as little
as one degree centigrade rise in temperature can
reduce the life of an amplifier by 10%. Mclntosh
has designed its amplifiers to maximize troublefree cool operation.
Output stages are mounted on super-sized heat
sinks that have maximum surface areas of cooling
capability. The sinks are placed in an air tunnel
chassis that occupies the amplifier space from top
to bottom. Cooling air, which flows through the air
tunnel, dissipates life-limiting heat. This heat
dissipation capability is coupled with a chassis
construction that encourages ventilation. A Mclntosh designed and manufactured autotransformer
matches the transistor output circuit to the
loudspeakers.
The Mclntosh output circuit uses 20 metal cased
bipolar epitaxial power transistors and 4 metal cased driver transistors. The output transistors feature
high fT (gain - frequency product) and large SOA
life
can be cut
short
without
the
pro-
• In the event of an output circuit failure, the
Mclntosh autotransformer conducts the speaker-
damaging DC (direct current) directly to ground,
thus protecting expensive loudspeakers from
potential damage.
• The Mclntosh autotransformer contributes a flex-
ibility in loudspeaker connecting capability not
otherwise possible. Here's how:
Ordinary amplifier output circuits are usually
restricted to operating in 4 or 8 ohms. In stereo,
the Mclntosh autotransformer perfectly matches
the output circuit to 2. 4, or 8 ohms. In mono
the MC7300 autotransformers provide matching
into 1, 2, 4, 8 or 16 ohms. In addition, the
autotransformer can provide either a 25 volt or a
70.7 volt output that can feed multiple
loudspeakers for background music applications.
Heat sinks
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The Mclntosh autotransformer is, quite simply, an
engineering advance that enhances amplifier
performance while maintaining technical and performance integrity.
Mclntosh's Exclusive Power Guard™
Music Protection Circuit
Improved recording techniques have imposed
higher power demands on today's amplifiers. Other
amplifier designs, of which there are many, can
present music listeners with unpleasant distortion
due to amplifier overload (hard clipping).
Clipping, which looks and acts like non-musical
square waves (music produces rounded waves), is
caused when the amplifier is required to produce
more power output (with low distortion) than it is
designed to deliver. Amplifiers, when driven to clipping, can deliver up to 40% harmonic distortiondistortion that significantly decreases listening en-
joyment, and increases listening fatigue. A clipped
Every detail of the complicated panel is inspected
and re-inspected.
The harmonic distortion and two-tone intermodulation measurements are important criteria in predicting the sonic performance. However, to obtain
better correlation with human hearing response,
we need to know not only the energy in the distortion spectrum, but also the number of discords
and their frequency spacing from the desired
tones. Spectral fidelity testing enlarges the scope
of
data
and
more
fully
clarifies
It is no accident, then that a Mclntosh amplifier is
a
smart
investment,
with years of audio excitement:
• It is more reliable than other amplifiers
• It has a longer, trouble-free life than other
amplifiers
• It sounds better than other amplifiers
• Its resale value is the highest of all amplifiers
one
that
its
will
meaning.
fill
your
home
Top interior view
signal also produces extra distortion energy, which
can damage speakers.
Mclntosh precision engineering has developed the
Power Guard circuit* to prevent amplifiers from being overdriven into hard clipping; ensure that the
amplifier produces its maximum output without increased distortion; and protect the speaker from
excessive heating.
(*Power
Guard
is a
#4048573)
Compact discs have a higher 'dynamic range' over
records and audio cassettes. Most compact discs
claim a dynamic range in excess of 90 decibels. In
numerical ratio this is greater than 1000 times the
ratio of popular commercial analog records.
For equipment to be digital ready it must handle
overdrive without breaking up or grossly distorting
the sound. Virtually all power amplifiers today are
incapable of accepting 10 decibels of overdrive
without gross distortion. Some amplifiers totally
collapse under this punishment. Mclntosh has
devised a test which shows an amplifier's spectral
fidelity
characteristics of an amplifier.
under
patented
stress
Mclntosh
-- one of the
design,
U.S.
most
patent
important
Mclntosh Patented Power Meters
In the past, ordinary power meters have been incapable of indicating the short interval information
in a soundwave, which can have a duration of one-
half of one thousandth of a second. And even if a
meter were capable of such high velocity movement, the human eye would be unable to perceive
the information.
Mclntosh engineering solved the dilemma by
developing an electronic circuit that power meters
can respond to with an accuracy of 98%. These circuits are time-stretched, which allows the meter
pointer position to register in such a way that the
human eye can register its high-speed motion.
The patented peak-reading, peak-locking meter circuit included in the MC7500 is yet another
Mclntosh electronic design feature that maximizes
your audio pleasure. . .and makes the MC73OO a
sound investment.
If
good
enough
will
do,
there are dozens of brands
to choose from.
But if the best is what you need
there is only one to consider:
The Mclntosh MC73OO.
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Performance Guarantee
Performance Limits are the maximum deviation
from perfection permitted for a Mclntosh instrument. We promise you that when you purchase a
new MC
will
be
capable
7300
from a Mclntosh franchised dealer,
of or can be
made capable
of
it
performance at or exceeding these limits or you can
return the unit and get your money back. Mclntosh
is the only manufacturer that makes this
statement.
Performance
Mclntosh audio power ratings are in accordance
with the Federal Trade Commission Regulation of
November 4, 1974 concerning power output claims
for amplifiers used in home entertainment
products.
Power Output
Stereo
300 watts minimum sine wave continuous average
power output, per channel, both channels
operating into 2 ohms, 4 ohms, or 8 ohms load im-
pedance, which is:
24.5 volts RMS across 2 ohms
34.6 volts RMS across 4 ohms
49.0 volts RMS across 8 ohms
Mono
6OO watts minimum sine wave continuous average
power output into 4 ohms, 8 ohms, or 16 ohms
load impedance, which is:
24.5 volts RMS across 1 ohm
34.6 volts RMS across 2 ohms
49.0 volts RMS across 4 ohms
69.3 volts RMS across 8 ohms
98.0 volts RMS across 16 ohms
Output Load Impedance
Stereo
2 ohms, 4 ohms, and 8 ohms; separate terminals
are provided for each output.
Mono
16, 8, 4, 2 or 1 ohms by connecting to proper output terminals.
Rated Power Band
20Hz to 20,000Hz
Total Harmonic Distortion
Stereo
0.005% maximum harmonic distortion at any
power level from 250 milliwatts to 300 watts per
channel from 20 Hz to 20,000 Hz, both channels
operating.
Mono
0.005% maximum harmonic distortion at any
power level from 250 milliwatts to 600 watts from
20Hz to 20,000Mz.
Intermodulation Distortion
0.005% maximum if instantaneous peak power
output does not exceed twice the output rating for
any combination of frequencies from 20Hz to
20,000Hz.
Frequency Response (at one watt
output)
20Hz to 20,000Hz +0 -0.25dB
l0Hz to 100,000Hz +0 -3dB
[Noise and Hum (A-Weighted)
105dB below rated output.
Ratings
IHF Dynamic Headroom
1.9dB
Damping Factor
Greater than 40
Input Impedance
20,000 ohms Unbalanced
40,000 ohms Balanced
Input Sensitivity
Switchable for either 1.4 or 2.5 volts
Power Guard
Clipping is prevented and THD does not exceed 2%
with up to 14dB overdrive at 1kHz
General Information
Power Requirements
120 volts, 50/60Hz, 0.6 to 13 amperes
Mechanical Information
Size
16 3/16 inches wide (41.1 cm) by 7 1/8 inches
high (18.1 cm) by 15 9/16 inches deep (4O.O cm),
including connectors. Knob clearance required is 1
inch {2.54 cm) in front of mounting panel.
Finish
The front panel is a combination of glass and black
anodized aluminum. The chassis is black.
Weight
79 pounds (35.8 kg) net, 97 pounds (44 kg) in
shipping carton.
The continuous improvement of its products is the policy
of Mclntosh Laboratory Incorporated who reserve the right
to improve design without notice.
Franchised Dealer:
039800
BE042003
Printed in U.S.A.
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CHAMBERS
MclNTOSH LABORATORY INC.
ST.,
BINGHAMTON,
NY
13903-2699
607-723-3512
Copyright 1991 © by Mclntosh Laboratory Inc.
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