Headphone Amplifier

High Quality unit, No need for a preamplifier

Circuit Diagram:

Parts:

P1 = 22K
R1 = 560R
R2 = 10K
R3 = 10K
R4 = 12K
R5 = 2.2R
R6 = 2.2R
R7 = 22R-1/2W
Q1 = BC337
Q2 = BC327
Q3 = BC337
Q4 = BC327
C1 = 1µF-63V
C2 = 100µF-25V
C3 = 100µF-25V
C4 = 100µF-25V
C5 = 22pF-63V
C6 = 22µF-25V
IC1 = NE5532
J1 = RCA audio input socket

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.

Source : www.redcircuits.com