Headphone Amplifier Based on RC4560

The project is utilizing dual op-amp chip TI RC4560 along with salt water-etched PCB, while using this SMD op-amp for headphone amplifiers.

The RC4560 is the active device inside the op-amp and is suitable for headphone amplifiers. It has low noise, wide bandwidth, and can work down to 2V. It is a small component that is available in TSSOP enclosure.

A gain of 11 is produced by the circuit, a standard non-inverting amplifier with a capacitive coupled input. The load is isolated by a small valued resistor at the output of the amplifier and any tendency of oscillation is minimized with long headphone leads. The input capacitors are placed outside, between the input jack, volume control and the board because their large size makes them too bulky to be included on board. A 9V battery is used to provide power where the 4.7K resistor is used to convert the voltage into dual 4.5V and decoupled by 220uF capacitors.

The indication that the circuit is ON is provided by a high efficiency LED that is fed with about 0.7mA by 10K resistor. One side of PCB is for signal and the other for power.

Rest of the project