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McIntosh Laboratory, the company who introduced
the world’s first amplifier that could be called “High
Fidelity”, has done it again. The McIntosh engineering
staff has created a power amplifier without com-
promise, using the most advanced McIntosh circuit
design concepts.
A continuous average power output rating of 300
watts and with an output current of greater than 50
amperes per channel, making this the most advanced
Integrated Amplifier McIntosh has ever manufac-
tured. The distortion limits for the MA8000 are no
more than 0.005% at rated power output for all fre-
quencies from 20Hz to
20,000Hz. Typical perfor-
mance at mid frequencies
is less than 0.002%. The
true distortion readings on
the MA8000 are so low,
it takes special measuring
techniques to make accu-
rate readings. The MA8000
can deliver the best possible
performance from any type
of high quality loudspeaker
system.
Creating an Integrated
Amplifier with this level of
performance did not come
easily. Many months of
design, testing and measur-
ing were required. Exten-
sive controlled listening
tests, the ultimate form
of measuring, were made
before the final design was
accepted.
Preamplifier Design Philosophy
Electro-Magnetic Switching is a proven technology
using the latest in materials and manufacturing meth-
ods. Each switch consists of a glass tube filled with
an inert oxygen-free atmosphere and sealed with tiny
leads protruding from ei-
ther end. Refer to figure 79.
These leads extend into the
tube and overlap one an-
other with a separation of a
few thousandths of an inch.
The leads are made from a
ferrous material that is influenced by a magnetic field.
They are first plated with gold as a base material, then
with rhodium and finally ruthenium. Ruthenium is the
best contact material known.
The glass assembly is then placed in the center of
a multilayer coil of copper wire. The entire assembly
is molded together in a tough shock absorbing mate-
rial. The switch and coil connectors extend from the
bottom in the form of printed circuit board terminals.
When a DC voltage is applied to the coil, current
flows and creates a magnetic field. The force of the
field causes the leads to bend and contact one another
inside the sealed glass tube. The inert gas eliminates
corrosion of the contacts and insures a low resistance,
distortion free switch. All Audio Signal Switching in
the MA8000 is done by 35 Electro-Magnetic devices.
Refer to figure 80.
Volume Adjustments
The most frequently operated control on a Integrated
Amplifier is the Volume Control. The desired volume
level can vary by the type of music, size of our listen-
ing room and even the time of day with which we
listen. So it is no surprise that McIntosh has devoted
Technical Description
MA8000 Top View
Figure 79
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