For anyone interested in audio projects, early projects are likely to be headphone amplifiers. It’s relatively easy to make transistors, integrated circuits or tubes, and you don’t need to be a genius in electronic engineering to make high-quality products. However, we rarely see miniaturized products like [daume Mo’s] usb-c DAC and headphone amplifier combination. It is installed in a slightly longer 3.5mm jack cover as part of a small USB to headphone cable.
The DAC is a ready-made board with an alc4042 IC, which has a line level output and a convenient place to disconnect the 5V line for the amplifier. The last part is a micro PCB with two chips. A tps65135 can produce clean + 5 and – 5 V tracks. An ina1620 is a high-quality audio amplifier set to 2x gain. All of these are designed on a very small PCB, which is located in the 3D printing housing together with the 3.5mm headphone jack. The result is a very neat unit that can drive high impedance headphones better than the unmodified DAC output, but still as small as any commercial product. We like it.
This may be one of the most compact USB to headphone amplifiers we’ve ever seen, but it’s by no means the first.