"... Mclntosh is
one of a kind
in the world of
quality audio..."
Mclntosh owner
M. C. Memphis, TN
Compact Discs have been proclaimed to have a large in-
crease in "dynamic range". Dynamic range is the ratio,
usually given in decibels, between the softest, quietest
sound on the disc and the loudest. Most Compact Discs
claim a dynamic range in excess of 90 decibels. In
numerical ratio this is greater than 1000 times the ratio of
practical commercial analog records.
For equipment to be "digital ready" it must be able to
handle overdrive without "breaking up" or grossly distor-
ting the sound. With one exception 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 new test
which shows the spectral fidelity of amplifiers under stress.
SPECTRAL FIDELITY is one of the most meaningful
characteristics of an amplifier. The harmonic distortion
and the two tone intermodulation measurements are im-
portant 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. This is
what the Spectral Fidelity testing can do, enlarge the
scope of the data and showing its meaning more fully.
In these oscillograms, you can see the difference in
Spectral Fidelity when a Mclntosh is stressed, and when
other amplifiers are stressed.
1. The Mclntosh stressed 10 dB above rated power.
2. A foreign amplifier stressed 10 dB above rated power.
3. An American manufactured amplifier which had to be
tested "under-stressed" since it could not take 10 dB
of overload.
The Mclntosh shows only 3 distortion components, which
are more than 44 and 50 dB down, roughly equivalent to
0.3% distortion. The other amplifier shows 17 discords,
some of which are only 10 dB down, or 30% distortion,
with many less than 30 dB down, or 3% distortion.
Note in the third oscillogram the complete failure of
one of the popular American manufactured amplifiers.
When 14 and 15 kHz are amplified at the same time, this
amplifier shuts down by "motor boating".
It is no accident that Mclntosh amplifiers sound better.
It is no accident that a Mclntosh is a better investment.
• It sounds better
• It is more reliable
• It last longer
• Its resale value is the highest
If good enough will do, there are at least 100 answers
for you. But if the best is what you need then there is
only one real answer....
....the amplifier that in 40 years has outlived 60 others
who have simply faded away.
SPECTRAL FIDELITY 15
