What EP600 version do you have and what actually broke off. If you have the older EP600 which has both RCA plug inputs and outputs, you simply use the output for an input(as Randy mentioned). This arrangement is like an internal "Y". The branch of the Y which is intended to carry the voltage out works just as well in the opposite direction.

If this is what you have, the cost is zero(unless you also break the RCA plug output off).

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Enjoy the music, not the equipment.