These are very good for just £11...

http://www.ebay.co.uk/itm/MUSE-HiFi-...item2c6730d3b9

They also do one already enclosed for £20. Fully isolated, headphone output and 1:1 pulse Tx on the SPDIF output....many CD players or streamers (IE: squeezebox) don't have the same attention to detail!

Only downside is the 48Khz limit, so no hires stuff.