S/PDIF to RCA conversion

SPDIF is a type of connection and not a type of connector. It can be optical or coaxial. TOSLINK, RCA and TS type optical (also known as Mini -Jack/Mini-Plug) are types of connectors being used for SPDIF connection. The TS Optical is used on some application but works liKE the Toslink a TOSLINK can even be converted to TS Optical Conncetor by placing a conversion casing around the tip, like this one. http://www.monoprice.com/products/ [...] 1&format=2

You can buy a Mini-Plug (TS) to RCA Coax cord or Mini-plug to TOSLINK optical cord but there's no cord that'll take you from TOSLINK optical to RCA or Mini-plug coaxial type, unless it has a conversion module attach to it. or something like:

Toslink to RCA conveter http://www.monoprice.com/products/ [...] t=2&style.
or
RCA to TTOSLINK Converter http://www.monoprice.com/products/ [...] 1&format=2

A hum usually indicates a ground loop on your system. Try using an extension cord that is plug from a different room and use it for your Sound System and your Computer or DVD Player and remove any cable or phone and network connection if any. If the hum still there then it's your computer, cords or your computer terminal that causes the hum.