Schematic Diagram You will need the following:

Assembly Instructions:

  1. Find the marking that indicates the primary winding (usually a blue or black band).
  2. Mark the hot phase of each winding with a magic marker such that it can be seen after the transformers are mounted. If you can't determine phase, mark the diagonally opposite terminals of both transformers. IMPORTANT! Make sure each mark is on a different winding (use an ohmmeter).
  3. Make holes in the box for the jacks and the screws to mount the terminal strips, PC board, or transformers.
  4. If using terminal strips, mount them to the box. If using a PC board, make mounting holes, but do not mount it to the box until told to. Make sure the transformers will not obstruct the mounting holes.
  5. Mount the transformers to the PC board or terminal strips. Be sure the transformer is supported by its mounting lugs, not the connections. Do not mount the PC board yet.
  6. Connect each transformer lead to a different circuit board pad or solder lug.
  7. Decide on a color code for hot, and ground. Wire all plugs using the same color code.
  8. Label one jack as ODD and the other as OUT.
  9. Connect the ODD jack to the primary transformer winding, connecting the hot to the hot phase, and the ground to the other end of the same winding.
  10. Wire the rest of the circuit according to the diagram.
  11. Finish assembling the box.


  1. Connect the phase switch in both channels of the leads from your sound source to your regular RM or Dolby Surround decoder.
  2. Set the switch to Swap.
  3. Play a surround sound recording through the switch and the Dolby Surround system.
  4. While the recording is playing, flip the switch to Reverse. This should cause the front and back images to trade places in the speakers.
  5. If the image does not change position, the transformer is wired wrong. Reverse the connections to the secondary winding.

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