How to Wire a Mono Cable to a Stereo Jack

By Joe Murray

Play your monaural signal from stereo speakers.
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When you play an amplified musical instrument through a multiple speaker system, play back older monaural records or tape or listen to a monaural source such as a speech or dictation recording through a stereo system, you may need to feed a mono signal into a stereo jack. There are two simple ways of accomplishing this: rewiring the mono cable plug and purchasing an adapter. Either method provides equally balanced signal to the stereo output.

Rewiring the Plug

Step 1

Remove the mono plug from the cable end. This method works with eighth- or quarter-inch audio plugs.

Step 2

Strip the leading portion of the cable to expose the center hot, or positive, lead usually covered in a white plastic coating and the silver-colored shielding surrounding it.

Step 3

Unscrew the barrel portion of the replacement stereo eighth-or quarter-inch plug and pull the mono cable through the rear of the barrel.

Step 4

Solder the exposed end of the center lead to both the positive center stereo pins on the rear of the stereo plug. Make sure to provide enough stripped center lead to touch both the center hot connectors of the stereo plug.

Step 5

Solder the shielded portion of the stripped mono cable to the ground of the plug, which is generally the longest of the three interior pins on the inside the stereo plug.

Step 6

Screw the barrel covering over the exposed connections and onto the stereo plug.

Step 7

Plug the rewired mono cable into the stereo jack and play a signal source. Sound should be emanating from all connected speakers at an equal volume level.

Using an Adapter

Step 1

Plug the mono plug at the end of the cable into the mono-to-stereo adapter.

Step 2

Plug the cable with the mono-to-stereo adapter into the stereo jack.

Step 3

Play a monaural signal source and listen to the individual speakers. Sound should be coming through each speaker at the same volume level.