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How to build 18watt Audio Amplifier

2015-01-02 22:52  
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Circuit Diagram:

Circuit Diagram

Circuit Diagram:

Circuit Diagram

Amplifier parts:

P1 = 22KR1 = 1KR2 = 4K7R3 = 100RR4 = 4K7R5 = 82KR6 = 10R-1/2WR7 = 22RR8 = 1K-1/2W (optional)C1 = 470nF-63VC2 = 100μF-3V Tantalum bead CapacitorsC3 = 470μF-25VC4 = 470μF-25VC5 = 100μF-3V Tantalum bead CapacitorsC6 = 100nF-63VD1 = 1N4148IC1 = TLE2141CQ1 = BC182Q2 = BC212 50V 100mA PNP TransistorQ3 = TIP42AQ4 = TIP41AJ1 = RCA audio input socket

Power supply parts:

R9 = 2K2C7 = 4700μF 25VC8 = 4700μF 25VD2 = 100V 4A Diode bridgeD3 = 5mm. Red LEDT1 = 30VCT, 50VA Mains transformerPL1 = Male Mains plugSW1 = SPST Mains switch


Can be directly connected to CD players, tuners and tape recorders.Do not exceed 23 23V supply.Q3 and Q4 must be mounted on heatsink.D1 must be in thermal contact with Q1.Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.Adjust R3 to read a current between 20 to 30 mA with no input signal.To facilitate quiescent current setting add R8 (optional).A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 & C4. Connect C6 to the output ground.Then connect separately the input and output grounds to the power supply ground.

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