Never had problems once I started using this from Radio Shack.
https://www.radioshack.com/product/index.jsp?productId=2102949 Of course if you have a mono jack, get the mono plug.
Cut it in half and you have TWO cables.
Strip the wires, connect them to the screws on a biscuit jack.
Connect cross-cut wire to the screws and run over to the 66-block.
The screws also give you a test point to make sure you have music. Just make sure you have a good ground and the ground/hot are on the correct wires.
