DESIGN PHILOSOPHY
The design philosophy incorporated in the MC500 involved many different techniques, all
based on sound scientific logic. Every stage of voltage or current amplification is designed
to be as linear as possible. Negative feedback is then utilized to enhance the performance.
Mclntosh engineers know how to properly design negative feedback circuits so they con-
tribute to the extremely low distortion performance expected from a Mclntosh amplifier. The
typical Mclntosh owner would never accept the approximately 100 times higher distortion
of many so called non-feedback designs.
All transistors are selected to have nearly constant current gain (Beta) over the entire cur-
rent range they must cover. Output transistors in particular, must have matched uniform
current gain, high current-bandwidth product and large active region safe operating area.
Resistors and capacitors in the signal path are carefully selected to have exceedingly low
voltage coefficients, (change of resistance or reactance with applied voltage). Precision metal
film resistors, low dielectric absorption film capacitors and premium audio grade electrolytics
are used in all critical circuit locations.
PROTECTION CIRCUITS
Some power amplifier manufacturers claim that their products do not need or do not use
protection circuits and that such circuits compromise performance. Mclntosh feels that pro-
tection circuits are desirable and necessary to prevent amplifier or loudspeaker damage due
to abnormal circumstances. The genius of Mclntosh engineering has resulted in protection
circuits which do not effect or compromise the normal performance of a power amplifier.
Six different types of protection circuits are incorporated in the MC500 to insure it a long,
safe and trouble free operating life. This is just one of the characteristics of Mclntosh power
amplifiers that have made them world famous. The SENTRY MONITOR circuit is a good
example.
SENTRY MONITOR CIRCUIT
All power transistors have limits for the maximum amount of power they can handle. The
MC500 output transistors and power supply have been designed to allow very high current
flow into properly matched load impedances. However, if a short circuit or very low load im-
pedance were connected to the MC500 outputs, destructive current levels could be reached
if it was not controlled by the Mclntosh SENTRY MONITOR circuit. This circuit senses the
dynamic operating time, voltage and current of the output stage, and controls it to safe
operating limits. The SENTRY MONITOR circuit does not limit the power output available from
the amplifier.
There is absolutely no compromise in sonic performance and it ensures safe operation
of the amplifier under even the most extreme operating conditions.
THERMAL CONTROL
All power transistors have limits to the maximum amount of heat they can safely tolerate.
The MC500 uses a highly efficient amplifying circuit which produces relatively little heat from
the power transistors for the output power produced. The amplifier uses large area heat sinks
with an area of more than 2800 square inches to efficiently dissipate the transistor heat. Natural
convection air flow is sufficient for safe cool operation. Cooling fans are not required.
If the cooling air is blocked, or the amplifier operating temperature is forced too high, ther-
mal cutout switches will turn off the AC power to the amplifier. When the problem is corrected
and the amplifier cools to its normal operating temperature, the AC power will turn back on.
TECHNICAL
DESCRIPTION
11
To Next Page
Loading...
Need help?
General
