PG light and a dynamic elec- tronic attenuator at the amplifier input reduces the input volume just enough to prevent any fur- ther increase in distortion. The Power Guard circuit acts so fast that there are absolutely no au- dible side effects and the sonic purity of the music reproduction is perfectly preserved. The MA6900 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 MA6900, there is a high voltage power supply for both channels. Refer to figure 17. The power amplifiers draw high current from the AC power line. Therefore, it is important that they plug directly into the wall outlet. Turn on inrush current is cushioned by thermistors in the power transformer’s primary circuit. This soft start eliminates component stress during
The MA6900 can provide greater than 50 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 MA6900 has the out- put current reserve to drive them. The MA6900 has 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 17
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