Headphone Amplifier

Since only a low power output is required, a Class A stage, is perfectly feasible. For adequate Class A operation the output transistors Q5-6, should pass say 100mA each. With ±15V supply this would mean 1.5Watts dissipation, so a smallish Heatsink, will be needed for each. With RV1 adjust input audio signal and Tr1 adjust the output DC Offset voltage for 0V (±30mV). For stereo application , you need two unit, of this amp.

Part list :

R1-4= 1.2Kohm R14=68Kohm C9-11= 100nF 100V ceramic
R2-3= 3.9Kohm RV1= 10Kohm Log. pot. Q1-3= BC184
R5=100Kohm TR1= 10Kohm Trimmer Q2-4= BC214
R6-10= 10Kohm C1= 4.7uF 63V MKT Q5= BD136 or BD538
R7-9= 2.2Kohm C2-7= 100uF 25V Q6= BD135 or BD537
R8= 150 ohm C3-5= 100nF 100V MKT
R11-13= 6R8 ohm C4-6= 100uF 16V
R12= 4.7 ohm C8-10= 470uF 25V All resistors is 1/4W 1%

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