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R1_____________10K 1/4W Resistor
R2____________100K 1/4W Resistor
R3_____________68K 1/4W Resistor (see notes)
R4______________1K5 1/4W Resistor
R5______________3K3 1/4W Resistor
R6____________330R 1/4W Resistor
R7______________4K7 1/4W Resistor
R8______________2R2 1/4W Resistor
C1______________1礔 63V Polyester Capacitor
C2____________100礔 25V Electrolytic Capacitor
C3____________470礔 25V Electrolytic Capacitor
Q1____________BC239C 25V 100mA NPN High-gain Low-noise Transistor
Q2____________BC337 45V 800mA NPN Transistor
Q3____________BC327 45V 800mA PNP Transistor
J1____________Stereo 3mm. Jack socket
SW1___________SPST Switch
B1____________3V Battery (two 1.5V AA or C cells in series)
Notes:
Can be directly connected to CD players, tuners and tape recorders.
Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 & 2000 Ohms.
Schematic shows left channel only.
B1, SW1, J1 & C3 are common to both channels.
R3 value was calculated for headphone impedance up to 300 Ohms. Using 600 Ohms loads or higher, change R3 value to 100K.
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