Jos van Eijndhoven has proved that high end audio equipment does not have to be bought at a store. His audio DAC (digital to analog converter) is proof that with lots of knowledge and some hard work it can be a DIY project!

“Features of this new DAC:

* Four separate SPDIF inputs are provided. For now one is configured as optical-in, the other 3 as coax-in. The microcontroller that is embedded in the DAC will search for a valid (active) input on these four channels.
* Each input channel can receive a digital audio signal at different sample rates. The proper input sample rate is automatically recognised. The DAC supports rates of 44.1kHz, 48kHz, 96kHz, and 192kHz, with all rates supporting 24-bit audio precision.
* A cheap potentiometer is used to provide a varying DC voltage to the microcontroller. The microcontroller reads this into a digital value, and then programs the DAC chips to adjust the output volume by scaling in the digital domain.”