Technical Description, con’t
able, since it can damage valuable loudspeaker sys- tem tweeters. You will never experience the harsh and damaging dis- tortion due to clipping.
The Power Guard cir- cuit is a waveform com- parator, monitoring both the input and output waveforms. Under nor- mal operating conditions, there are no differences between the shape of
these waveforms. If an amplifier channel is overdriven, there will be a difference between the two signal wave- forms. When the difference exceeds 0.3% (equivalent to 0.3% harmonic distor-
tion), the Power Guard activates the PG light and a dynamic electronic at- tenuator at the amplifier input reduces the input volume just enough to prevent any further in- crease in distortion. The Power Guard circuit acts so fast that there are ab- solutely no audible side effects and the sonic pu- rity of the music repro- duction is perfectly pre-
served. The MC602 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 fully balanced design of the MC602, there are two high voltage power supplies; one for each channel, allowing each channel to be optimized using its own power supply. Refer to figure 18. High power amplifi- ers draw high current from the AC power line. Therefore, it is important that they plug directly into the wall outlet.
Also, most owners desire that there be one power switch for the whole audio system. The MC602 is equipped with a circuit that provides remote Power Control from your McIntosh Preamplifier or Control Center. When you turn on your preamplifier a digital “1” (+5V) signal oper- ates the power relay in the MC602. The MC602 also has a remote Power Control Out Jack. The Power Control signal from this jack is delayed by a fraction of a second so that the turn on power surge of the next power amplifier occurs at a later time. This helps prevent power circuit overload that could trip circuit breakers or blow fuses, a very impor- tant feature in a high power Home Theater System employ- ing three MC602 Power Amplifiers.
The MC602 can provide greater than 150 amperes peak output current to drive uneven speaker loads. Some poor speaker designs have input impedance that dip to 1 or 2 ohms at various frequencies and the MC602 has the output current reserve to drive them. It can deliver over 1,000 Watts Output on tone bursts. The MC602 has huge main filter capacitors that guarantee an excellent signal to noise ratio and the energy storage necessary for the wide dy- namic range that “Digital Audio” demands.
Block Diagram |
of the |
Power Supply |
Figure 18
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