McIntosh MC1.2KW User Manual

15

cies is less than 0.002%. The true distortion readings 

on the MC1.2KW are so low, it takes special measuring 

techniques to make accurate readings. The MC1.2KW 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.

The design philosophy incorporated in the MC1.2KW 

involved several different techniques, all based on sound 

scientific logic. Every stage of voltage or current ampli-

fication must be as linear as possible prior to the use of 

negative feedback. McIntosh engineers know how to prop-

erly 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 double balanced configu-

ration cancels even order distortion. Refer to figure 12.

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 product and large 

active region safe operating area. An automatic tracking 

bias system completely eliminates any trace of crossover 

distortion. 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 MC1.2KW Out-

put Autoformer. It provides low distortion power transfer 

at frequencies from below 20Hz to well beyond 20,000Hz 

with optimum impedance points of two ohms, four ohms 

and eight ohms. The unequaled expertise of McIntosh in 

the design and manufacturing of autoformers is legendary 

in the high fidelity industry.

The 

high ef-

ficiency 

circuit de-

sign of the 

MC1.2KW 

contrib-

utes to low 

operating 

tempera-

tures. More 

than 2800 

square 

inches of 

heat sink 

area keep the MC1.2KW operating safely with convection 

cooling. No fans are needed. Refer to figure 13.

Figure 12

Figure 13