Owner`s manual

14
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 compro-
mise, using the most advanced McIntosh circuit design
concepts.
The MC601 has a continuous average power output
rating of 600 watts and with a peak output current of
90 amperes; making this one of the most advanced
amplifiers available today. The distortion limits for
the MC601 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 MC601 are so low, it takes
special measuring techniques
to make accurate readings. The
MC601 can deliver the best
possible performance from any
type of high quality loudspeaker
system. Refer to figure 12.
Creating an amplifier with
this level of performance did
not come easily. Many months
of design, testing and measur-
ing were required. Extensive
controlled listening tests, the ul-
timate form of measuring, were
made before the final design
was accepted.
Design Philosophy
The design philosophy incor-
porated in the MC601 involved
several different techniques,
all based on sound scientific
logic. Every stage of voltage or
current amplification must be
as linear as possible prior to the
use of negative feedback. McIn-
tosh engineers know how to properly design negative
feedback circuits so they contribute to the extremely
low distortion performance expected from a McIntosh
amplifier. The typical McIntosh owner would never
accept the approximately 100 times higher distortion
of many non-feedback designs.
Double Balanced Push-Pull design is used from
input to output. Each half of the amplifier contains
complimentary balanced circuitry. The resulting Quad
Balanced configuration cancels even order distortion.
Refer to figure 15.
All transistors are selected to have nearly constant
current gain over the entire current range they must
cover. Output transistors in particular, have matched
uniform current gain, high current bandwidth prod-
uct and large active region safe operating area. These
Power Transistors are the very latest in semiconduc-
tor technology and incorporate a new design known
as ThermalTrak™. Refer to figure 13. This allows for
the instantaneous and accurate monitor-
ing of the Power Transistor Temperature.
The MC601 Power Output Circuitry has a
specially designed bias circuit to take full
advantage of the ThermalTrak™ Power
Transistors and thus precisely controls
the power amplifier operation over a
wide range of music conditions with the
benefits of lower distortion and cooler
operation. Precision metal film resistors
and low dielectric absorption film capacitors are used
in all critical circuit locations.
The output signals of the two balanced circuits
are coupled together in the unique McIntosh MC601
Output Autoformer. It provides low distortion power
transfer at frequencies from below 20Hz to well
Technical Description
Figure 13
Figure 12