The voltage needed to run IC LM4880 is between 2,7VDC up to 5VDC. R1 and R2 from the circuit that serves as a feedback. Meanwhile, C4 and C5 is a decoupling capacitors so that the DC voltage is not entered. C3 in the circuit will reduce the noise of the input sensitivity.
HiFi Headphone Amplifier Circuit Based LM4880 has distortion rate 0.1% when the circuit was at work. Believe me, this amplifier circuit will produce high-quality audio with a minimum components.
The headphone amplifier can generate 250mW output power in standard headphones. A few notes for you when it will assemble the headphone amplifier circuit, use a good quality PCB, and use the power supply that is regulated as well as using the IC regulator 7805. Or it would be better if this circuit works using the battery.
HiFi Headphone Amplifier Circuit Based LM4880 Parts list :
R1, R2 : 20K
R3, R4 : 0.47 OHM
C1, C2 : 220uF
C3 : 0.1uF
C4, C5 : 1uF
IC : LM4880