200W PA Amplifier PUBLIC

200-Watt PA Amplifier

200-watt RMS public-address (PA) and sound-reinforcement amplifier circuit. Controls include only Input Level and Volume. No tone controls. Actual RMS output = 192-watts, with average output of 270-watts and peak clipping output at 307-watts. Range is from 38 Hz to 6 kHz with both controls at 50%, or 22.4 Hz to 11 kHz with both controls at 100%. Maximum gain = +17 dBV @ 400 Hz with both controls at 50%, or +30 dBV @ 400 Hz with both controls at 100%. With an 8-ohm load, THD+N = 0.004% @ 1-watt, and 0.001% @ 200-watts, from 1 kHz to 20 kHz, given specified resistor tolerances. However, with higher tolerances (i.e., less expensive resistors), THD+N will increase accordingly. More normal tolerances can be used for sound-reinforcement applications where more noise is not an issue. But for high-fidelity and full-range PA applications, the specified tolerances must be observed. Power-supplies not shown. The circuit requires two dual-polarity DC supplies: one +-15 VDC providing >= 20 mA of current, and one +-45 VDC providing 4 A of current. Treat the circuit as experimental. Breadboard test before soldering.