The latest version of PCM2912 USB V1.3 version of the sound card, using more advanced design, more advanced devices, to enhance your computer sound card performance. (tantalum capacitors, Murata Akizhen, gold plated sockets, Mirc-USB data lines)
Because it is designed by itself, PCB did not find the right shell, manual welding (hot air gun + electric iron), mind careful pat!
Sound card shape display: 8.2*2.2cm
Interface: Mirc-USB (Android phone data line), gold-plated headset socket, gold-plated microphone socket
Key: Mute microphone
Switch: Power Mode (energy saving mode switching, the use of notebook batteries, the use of this model can save a lot of power)
MIC Gain (MIC gain control, 0dB and +20dB control)

PCM2912 is a TI high end sound card chip, its excellent performance in various types of high-level power amplifier have been adopted, loved by the vast number of enthusiasts.
I designed the 1, 1.1, 1.2 version of the sound card, analysis of its strengths and weaknesses, designed version 1.3, more delicate treble, more surging and flexible bass, so that you enjoy the wonderful music. I personally tested, super love voice test, bunker!! At the movies, in the continuous integrated sound card sound card and desktop on the movie to hear more details of the sound, like a bullet shell landing sound, the sound of rain, roar ~ ~ ~ ~ with exquisite detail and deep bass. TV, watching "iron teeth copper Ji Fourth", the use of computer integrated sound card was to hear a man's voice slightly burr, not clear, change to the USB card, can restore the true sense of hearing, enhance sound quality is very obvious.

This design version adds two main parts: power supply low-pass filter and HIFI amp TPA152.
The following is a filter circuit display

Type RC low pass filter filter, effectively reduce the ripple and noise of the computer USB power supply, to enhance the quality and reduce the noise floor provided solid power, two 470uF tantalum capacitors (advanced super capacitors, filter performance and long life, superior price is more expensive, please provide sufficient energy, Baidu) for the dynamic bass! The capacitance above above, using imported from Japan, Murata Akizhen, provides a more accurate clock and low temperature drift (PCM2912 chip, will generate heat, the temperature drift of small components, can avoid the sound signal difference).
Gold-plated earphone socket

Beside the gold-plated headset socket, you can see a TPA152 amp chip. The chip from TI company manufacturing amp.
Normal working condition:

The microphone is switched on: