Troubleshooting: Soldering new headphone plug

Question

I have Sony MDR-7506 headphones. The isolation of the cable near the original plug embrittled over time and fell off. Therefore, I cut off the cable at that spot to replace the original plug with a new one.

There are 3 small wires inside: 2 rose ones and 1 black one. I connected the black wire to the Ground and the rose ones to the left and right connection of the plug, respectively.

Now, when listening to stereo signals, I've made the following observations: The right audio appears on the right ear (correct). The left audio, however, appears to be centered, whereas the centered sounds seem left.

Honestly, I have no explanations for these observations because I thought that centered sounds are produced by left and right sounds with the same amplitude and the only errors I could observe are either left and right sounds are swapped or no sound at all on either or both sides.

Can you please give me a clue about what could happened. What happens if I swap one of the directional wires (of the left or right earphone) with Ground?

Answer 1

Suggests that the black wire may not be ground (unlikely, but I've seen stranger things), or that you've soldered it to the wrong contact of the new jack, or that you have a short.

Verify that you are soldering to the intended pins on your new plug.

Check also that you don't have any shorts - it's possible you've shorted left/ground or right/ground.

If that doesn't work, I'd suggest cutting open the original plug to see where each of the wires goes. This will get you to two possible options (two orientations of pink wires), try both to see which works.

Answer 2

I swapped the left and ground wire and now, it works. The reason for this issue was that the left wire was connected to ground and the ground wire was connected to the tip of the plug.