McIntosh MA6900 User Manual

Page 18

Technical Description

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 cre-
ated a power amplifier without compromise, using the most
advanced McIntosh circuit design concepts.

A continuous average power output rating of 200 watts

and with an output current of greater than 50 amperes per
channel, making this the most advanced Integrated Ampli-
fier McIntosh has ever manufactured. The distortion limits
for the MA6900 are no more than 0.005% at rated power
output for all frequencies from 20Hz to 20,000Hz. Typical
performance at mid frequencies is less than 0.002%. The
true distortion readings on the MA6900 are so low, it takes
special measuring techniques to make accurate readings.
The MA6900 can deliver the best possible performance
from any type of high quality loudspeaker system.

Creating an amplifier with this level of performance did

not come easily. Many months of design, testing and mea-
suring were required. Extensive controlled listening tests,
the ultimate form of measuring, were made before the final
design was accepted.

Preamplifier Design Philosophy
All signal switching in the MA6900 is done by Electro-
Magnetic devices. Electro-Magnetic Switching is a proven
technology that uses the latest in materials and manufactur-
ing methods. Each switch consists of a glass tube that is
filled with an inert oxygen-
free atmosphere and sealed
with tiny leads protruding
from either end. These leads
extend into the tube and
overlap one another with a
separation of a few thou-
sandths of an inch. The leads
are made from a ferrous ma-
terial that is influenced by a
magnetic field. They are first
plated with gold as a base
material, then with rhodium
and finally ruthenium. Ru-
thenium 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 material.

Bottom Inside View of the MA6900

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

Equalizer Control Adjustment Range

Hz (Hertz)

(Decibel)

Figure 10