In this project I’m build USB sound card using single chip and it produce good audio output and compatible with Windows 9x operating systems and Windows NT family operating systems (I am not tested this circuit with Windows Vista and chip manufacturer say it is worked with Mac OS also) This is a plug and Play device and device driver is not required. Special feature of this sound card is its built-in HID controller. Using this HID controller user may be able to control Windows Volume control using 3 buttons located on the sound card. These buttons are used for Volume Up, Volume Down and for Audio Mute.
This device is based on Burr-Brown’s PCM2904 USB CODEC chip and it produces stereo output. PCM2904 operates using USB power (self powered) and external power adapter is not required.
I think this device is ideal for USB headphones or mini-speaker modules. My implementation is 10x9 cm. I spend Sri Lankan Rs. 1500 for this circuit.