I am the original owner of a factory-built model (they were also sold as kits) and am selling it as my current DAC has a built-in USB input. Rated 8/10 for age as it is just under four years old.
These converters were very well reviewed and are no longer available new. They are an excellent way to use one of the many great DACs that don't have a USB input with a computer-based music server. I used it to connect a Meridian DAC to an Apple Mac Mini and it worked very well.
The S/PDIF (aka SPDIF) output is via an RCA jack.
For more information please see http://www.hagtech.com/hagusb.html
Shipping via USPS Priority included in asking price. Sorry, but I will not ship outside of the US.
Please feel free to ask any questions you may have by emailing me at jacopo at jbotta dot com. I've had a lot of problems answering questions posted through the website.