McIntosh MC-2205 Brochure
Mclntosh engineering has advanced power amplifier
technology and performance five times since 1949. Experience
and knowledge are the foundation on which the
engineering superstructure is built that supports
the fact that Mclntosh is recognized as Laboratory
Standard for the world. A new level of
technology and atigher level of amplifier performance is realized in the NEW
MC 2205 Power Amplifier.
BIPOLAR EPITAXIAL
RESEARCH AND
TRANSISTOR TECHNOLOGY
• Mclntosh life testing of components permits component selection for trouble-free performance;
added care in production engineering and manufacturing results in long product life
HAS PRODUCED
MclNTOSH
• Mclntosh engineers developed a unique output
stage circuit arrangement that is completely
temperature accurate that delivers clean output
power at any level without crossover distortion
• Mclntosh POWER GUARD assures maximum amplifier power without
clipping distortion
• Mclntosh Output Autotransformer delivers full power output and multiple
feedback loops assure lowest distortion at all power levels and all
speaker impedances
• Mclntosh designed turn on/mute circuits provide positive protection from "turn-on transients"
and other potentially
damaging noises
AMPLIFIER PERFORMANCE
NEW ADVANCES
STARTLING
SUPERIOR
IN SAFE
COOL
Shown in optional
walnut veneer cabinet
MC
2205
Higher power demands on amplifiers
have presented music listeners with a
form of unplesantness in listening,
amplifier overload (hard clipping) that
looks and acts like square waves. Clipping
is caused when the amplifier is asked to
produce more power output with low
distortion than it can deliver. Clipping of a
complex wave form is largely composed of
odd order harmonics and intermodulation
products. High order odd harmonics and
intermodulation products are dissonant
and are not musically related to the signal
being amplified. They are heard as great
and disappointing discordance and
distortion.
In the past years Mclntosh has
substantially improved the ability of
amplifiers to deliver lower distortion
within their rated power. The
improvement has removed the masking
of the unpleasant, harshly distorted
sounds of clipping. Music demands high
peak power reproduction ability without
clipping.
Although we may listen to surprisingly
low average power output, the peak power
requirements can be very high. Consider
these graphs of the power demanded of an
amplifier reproducing the pipe organ, the
piano, and the bass saxophone. The charts
show that the peak power demands is
almost 30 dB or 1000 times the average
power demand. Since it is necessary that
these short interval power spikes be
reproduced with low distortion, it means
the average power output of the power
amplifier must be limited to l/1000th of
its capability or the listener must accept
the discordant distortion of clipping.
2.0 PIANO 10 FT.
30
IN dB
AVERAGE
TO
0
PEAK
PRESSURE
OF
TOTAL
RATIO
-30
20 100 1K 10K
FREQUENCY IN HERTZ
DISTANCE
2.1 PIPE ORGAN 12 FT.
30
0
-30
20 100 1K 10K
.
Amplifiers when driven to clipping are capable of delivering
up to twice the heat load to the loudspeaker. In addition, they
can have more than 40% harmonic distortion. The extra heat
energy content of the clipped signal will damage most speakers. Mclntosh leadership in engineering has developed a new
circuit that ... (1) dynamically prevents power amplifiers
from being overdriven into hard clipping ... (2) which reduces
the heat developed in the loudspeakers ... (3) assures that the
amplifier will produce its maximum output without increased
distortion. That new circuit we call "POWER GUARD."
FREQUENCY IN HERTZ
causing a waveform difference of 0.5% in the output the indicators change from green NORMAL to red LIMIT automatically
and instantaneously. You are always assured that the power
of your amplifier is as clean and distortion free as it can be.
DISTANCE
4.1 BASS SAXOPHONE
30
0
-30
20 100 1K 10K
FREQUENCY IN HERTZ
DISTANCE
3.5 FT.
HOW POWER GUARD WORKS
In Power Guard, a waveform comparison circuit detects
minute amounts of waveform difference between the output
signal and the input signal. A sampling of the program material
at the output of the amplifier is constantly compared with the
program material at the amplifier input. You are alerted, by a
front panel indicator, to waveform differences of 0.5%. Should
the differences reach 1%, Power Guard goes to work. Power
Guard dynamically reduces input level to prevent amplifier
overload yet permits the amplifier to deliver its absolute maxi-
mum power output without extra distortion.
In addition, the output of the "waveform comparator"
activates the front panel NORMAL and LIMIT indicators. Any
time that the input circuit is fed excessive amounts of signal
Oscillogram of output waveform with and without Power Guard. Input
overdriven for each trace 20 dB.
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