105W Simple Power Amplifier

105W simple power amplifier is designed for typical connection circuit for IC LM3876T company National Semiconductor and is powered by bipolar unregulated power supply voltage of ± 35 V. The opening of the switch S1 turns on mute.

Despite the simplicity and lack of adjustment elements,
-the amplifier has high performance
-ratio IMD (SMPTE 60 Hz, 7 kHz, 4:1) does not exceed 0.004%,
-typical THD 0.01%, noise level -114 dB,
-frequency response ( -3 dB) 10 Hz to 90 kHz or 20 Hz … 20 kHz ± 0,25 dB level,

So it is suitable for audio of the highest class. The gain is given by Ki = 1 + R9 / R4. The coil L1 is wound around a 2-watt (such as MLT-2) and resistor R8 has 14 turns of wire 1.3 mm in diameter. Chip to the radiator to the thermal resistance of not more than 3 ° C / W («RADIO T9» № 7-8 / 2005 sec. 14, 15 *).