A simple miniature amplifier built on a specialized low-voltage microcircuit, the LM386 audio amplifier can be used as a low-power headphone amplifier. This is true in a situation where the signal from some device, such as a portable player or phone, is not strong enough to swing the speakers of your headphones.
This designer has all the necessary parts along with a printed circuit board - all that remains is to solder electronic components into the drilled holes, apply power, an audio signal and get an amplified signal at the output.
Naturally, this device, based on the tiny LM386 microcircuit, will not be able to provide high quality amplification, but its price is corresponding. By default, power is supplied through a 2.1 mm jack (it is also possible through PLS pins), the input voltage ranges from 3 to 12 V. As a power source, you can use any charging phone, USB port or any network power supply with minimal ripple at the output . Below you see a list of all the components included in the amplifier circuit.
This amplifier, according to the seller, is capable of “swinging” dynamic heads with power from 0.5 to 10 watts. The volume is controlled by a variable resistor of 100 kOhm, connected at the input. An analog signal is fed through the 3.5 mm audio jack or PLS pins, the amplified output signal is removed from the PLS pins. Board dimensions 37 by 41 mm. A glowing red LED indicates power to the circuit.
Cost: ~ 58