Wiring Schematic Diagram

Headphone Amplifier

This electronic circuit is a high quality headphone amplifier. It's no need for a preamplifier. This circuit equipped with a symetrical power supply.




Amplifier parts list:

P1 - 22K Log.Potentiometer (Dual-gang for stereo)
R1 - 560R 1/4W Resistor
R2,R3 - 10K 1/4W Resistors
R4 - 12K 1/4W Resistor
R5,R6 - 2R2 1/4W Resistor
R7 - 22R 1/2W Resistor
C1 - 1µF 63V Polyester Capacitor
C2,C3,C4 - 100µF 25V Electrolytic Capacitors
C5 - 22pF 63V Polystyrene or Ceramic Capacitor
C6 - 22µF 25V Electrolytic Capacitor
IC1 - LM833 or NE5532 Low noise Dual Op-amp
Q1,Q3 - BC337 45V 800mA NPN Transistors
Q2,Q4 - BC327 45V 800mA PNP Transistors
J1 - RCA audio input socket

Power supply parts List:

R8 - 2K2 1/4W Resistor
C7,C8 - 2200µF 25V Electrolytic Capacitors
D1 - 100V 1A Diode bridge
D2 - 5mm. or 3mm. Red LED
IC2 - 7815 15V 1A Positive voltage regulator IC
IC3 - 7915 15V 1A Negative voltage regulator IC
T1 - 220V Primary, 15 + 15V Secondary 5VA Mains transformer
PL1 - Male Mains plug
SW1 - SPST Mains switch

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 Ohm.
Old 8 Ohm impedance headphones can be also driven, but these obsolete devices are not recommended.
Schematic shows left channel and power supply (common to both channels).
Numbers in parentheses show IC1 right channel pin connections.
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. Then connect separately the input and output grounds to the power supply ground.