Specifications

Rear Panel Information
OUTPUT
Output connections for impedances of 2, 4 and 8
ohms are provided on secure, screw type, gold plated
terminals.
INPUT
A balanced and unbalanced input are provided.
AC POWER
The MC1000 is rated for 120 volts, 50/60 hertz.
Technical Description
The MC1000 is a power amplifier designed to
operate with a loudspeaker having a nominal impedance
of 2, 4 or 8 ohms.
It features a new circuit design that holds harmonic
distortion far below the amplifiers remarkably low noise
floor. Only by using special spectrum analysis
measuring techniques is the distortion measurable at
all.
DESIGN PHILOSOPHY
The secret to this performance will sound very
simple, but it is more difficult to carry out than it may
seem. The principle used in the design of the MC1000
was to arrange every stage of voltage or current
amplification to be as linear as possible.
This linear operation is accomplished by using
several different techniques.
1. Each transistor is selected to have nearly constant
current gain (Beta) over the entire range of currents
at which the transistor must operate.
2. The load impedance presented to each amplification
stage is made to be as uniform as possible for all
signal levels.
3. The input impedance of stages is increased and
linearized where possible by using emitter degener-
ation.
4. Resistors and capacitors in the signal path are
carefully selected to have exceedingly low voltage
coefficients (low change of resistance or reactance
with applied voltage). Precision metal film resistors
and low dielectric absorption film capacitors are
used in all critical circuit locations.
5. Output transistors have matched uniform current
gain, high current gain-bandwidth product, low
output capacitance, and large active-region safe
operating area. These characteristics and the
automatic tracking bias system eliminates cross-
over distortion. The distortion graphs show
clearly that distortion does not increase at low
power output levels.
OVER 400 JOULES OF ENERGY STORAGE
Huge main filter capacitors are used to guarantee
an excellent signal to noise ratio and the energy storage
necessary for the wide dynamic range that "Digital
Audio" demands.
ILLUMINATED, PEAK RESPONDING OUTPUT
WATTMETER
The MC1000 is the first high power amplifier to
have a REAL OUTPUT WATTMETER. The power output
in WATTS of any amplifier is determined by multiplying
the output voltage (E) by the output current (I), El = W.
Output meters on other amplifiers are only voltmeters.
Output current is not considered. Calibration is in watts
and is based on the false premise that all speakers have
a fixed impedance regardless of frequency. In fact, the
impedance of many poor speakers designs varies by as
much as 4 to 1. For a specific output voltage the
current varies inversely to the speaker impedance. So
if the speaker impedance is lower, the output current
and power are higher. Since Mclntosh can not control
other manufacturers speakers, we decided to provide
extra output current to drive these mismatched low
impedances and to indicate the REAL output power
required to drive them. Therefore the meter circuit in
the MC1000 electronically measures both voltage and
current, multiplies them and displays the REAL OUTPUT
POWER IN WATTS.
Another important feature of these output
wattmeters is their ability to respond 95% full scale to
a single cycle tone burst at 2kHz. After voltage and
current are measured and multiplied, the product is fed
to a special circuit that accelerates the meter pointer
in the upward direction. When it reaches its peak, it
pauses only long enough for the human eye to perceive
its position, then returns to 0. Response is almost 10
times faster than a professional VU meter.
A front panel switch is provided to change the
meter to the WATTS HOLD mode of operation, fast
upward movement of the pointer but greatly increased
MClNTOSH LABORATORY INC., 2 CHAMBERS STREET, BlNGHAMTON, NEW YORK 13903
MC1000 Product Preview/Page 5