converting standard cable to balanced

Some cables can be re-terminated and some can not. For example, Cardas and Hamonic Tech can (I've done it) and WireWorld can not because apparently they use a different cable for the balanced version of Eclipse or whatever vs. the unbalanced version. Check with Monster and see if they can and will do it for you.

Ernio1- there are adapters available, but I'm not sure if that will do what you want. Anyways, Markertek (pro-audio) has a good name (Neutrix) and v good prices compared to hi-fi prices.

You cannot convert the cable since standard cable has only a
single lead plus the shield and balanced cable requires, at least, 2 signal leads (+ and -) and a ground lead. While you can add a transformer at each end to connect your cable to balanced sources and loads, you will not have a balanced connection.