Step 5: Prepare the Wires on the Receiver
The only parts on the receiver that we will be modifying are the wires that went to the original speaker. First we need to determine the polarity of the speaker. Most speakers have their positive and negative terminals labeled. But if they are not labeled, you will need to determine this by examining how they are hooked up to the circuit board. In my receiver, one speaker wire is connected to the positive supply voltage (the red wire). I am calling this the positive speaker wire. The other speaker wire is connected to the volume control transistor. I am calling this the negative speaker wire.
Cut the positive speaker wire as close to the circuit board as possible. This leaves you with a loose piece of wire. Strip at least 1/2" of insulation off both ends. On the negative wire, strip off at least 1/2" of insulation from the free end.