As [Jan-Erik] had already built a simple USB connected Digital-to-Analog Converter (DAC), he decided to make ... put between single quotes because the PCB is single sided and uses through hole ...

The DAC is an off-the-shelf board featuring an ALC4042 IC, it has a line-level output and a handy place to tap off a 5 volt line for the amplifier. This final part is a tiny PCB with two chips ...