Specifications

accept signal. For BRIDGED operation use only the 1,
3, & 5 input jacks and place the MODE switch in the
BRIDGED position.
The THX connector is used when the MC7106 is
connected to a THX Surround Decoder. It contains all
six channel inputs and AC power control.
OUTPUTS
For normal operation, output connections for
impedances of 4 to 8 ohms are provided on secure,
screw type, gold plated terminals. Connections for
BRIDGED output are marked above the terminals.
AC POWER
The MC7106 is rated for 120 volts, 50/60 hertz.
It uses .8 amperes when there is no signal output and
up to 19 amperes with all channels delivering rated
power. A 15 ampere fuse protects the MC7106 electri-
cally.
AC POWER SWITCH
The POWER switch has two positions. ON and
REMOTE. The REMOTE position provides a circuit that
operates the power relay from a logic "1" (5V) signal.
This signal can be applied between pin 13 (input) and
pin 25 (control ground) of the THX connector or to the
POWER CONTROL IN jack (tip-input, sleeve-control
ground). The POWER CONTROL OUT jack provides a
power ON signal for the NEXT power amplifier. This
signal is delayed by approximately .2 seconds so that
inrush current peaks are sequenced.
Technical Description
The MC7106 is a six channel power amplifier
designed to operate with loudspeakers having a nominal
impedance of 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 MC7106
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 degen-
eration.
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 150 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.
PROTECTION CIRCUITS
Some manufacturers of power amplifiers
advertised that their products do not require or use
protection circuits and that such circuits compromise
performance. Mclntosh Laboratory agrees that diligent
measures are required to allow unrestricted performance,
but we also insist that protection circuits are desirable
and necessary to prevent amplifier or loudspeaker
damage due to abnormal circumstance and that they
actually enhance performance. The MC7106
incorporates seven protection circuits to enhance its
performance, assure its reliability and to protect
loudspeakers.
POWER GUARD
Power Guard, a unique feature of Mclntosh
amplifiers, assures that each channel of the MC7106
will deliver full power free of clipping distortion. Clipping
MCINTOSH LABORATORY INC., 2 CHAMBERS STREET, BINGHAMTON, NEW YORK 13903
MC7106 Product Preview/Page 3