With Power Guard
Figure 20
Technical Description, con’t
but the inaudible ultrasonic dis- tortion is also undesirable, since it can damage valuable Loudspeaker System tweet- ers. You will never experi- ence the harsh and damaging distortion due to clipping.
The Power Guard circuit is a waveform
comparator, monitoring both the input and output wave- forms. Under normal operating conditions, there are no dif- ferences between the shape of these waveforms. If an am- plifier channel is overdriven, there will be a difference be- tween the two signal waveforms. When the difference ex- ceeds 0.3% (equivalent to 0.3% harmonic distortion), the Power Guard activates the PG light and a dynamic elec- tronic attenuator at the amplifier input reduces the input volume just enough to prevent any further increase in dis- tortion. The Power Guard circuit acts so fast that there are absolutely no audible side effects and the sonic purity of the music reproduction is perfectly preserved. The MC207 Power Amplifier with Power Guard is not limited to just the rated power output, but will actually produce distortion free output well above its rated power due to the McIntosh philosophy of conservative design.
Power Supply Circuits
To compliment the design of the MC207, there is a high current power supply for the seven power amplifier chan- nels. Refer to figure 21. The very large Power Transfomer, has toroidal windings on a toroidal core and can supply over 35 amps of continuous current. Refer to figure 22 (golf ball is for size comparsion). It is enclosed in the leg- endary McIntosh Potted Enclosures and weighs over
Figure 22
12.06kg. The super size main filter capacitors can store over 430 Joules of energy for the seven amplifier channels, necessary for the wide dynamic range that “Digital Audio” demands. Refer to figure 23. The power amplifier draws high current from the AC power line. Therefore, it is im- portant that they plug directly into the wall outlet.
Also, most owners desire one power switch for the whole audio system. The MC207 is equipped with a circuit that provides remote Power Control from a McIntosh A/V
Block Diagram |
of the |
Power Supply |
Figure 21
19
