A small audio project I am doing is producing mono audio right now. To stop annoying my family I added a headphone trs socket as an alternative for the (single) speaker. audio (-) is wired to the sleeve and audio (+) to the tip and ring, so that I hear it left and right. Unfortunately the signal on the left is coming out relatively quiet.

Should it work this way? Or should I just add a mono trs socket and the headphones will do the right-thing (TM) and duplicate the tip signal?

  • \$\begingroup\$ I think it is an impedance issue, you should not directly connect the audio single output to both the speakers, you have to use a power divider to send the power equally to both speakers. I'm not sure so i'm posting this as a comment \$\endgroup\$
    – MaximGi
    Feb 16, 2016 at 10:59
  • \$\begingroup\$ It is unclear to me what you're doing. As it is a mono signal, just connect both left and right from the headphones to the tip of the plug. Ignore the ring as it will be grounded if the output jack is not stereo (that could explain why left has no sound). \$\endgroup\$ Feb 16, 2016 at 14:08
  • \$\begingroup\$ Your wiring sounds correct to me. Check your wiring is good. It's always possible that the headphones themselves are poorly balanced. \$\endgroup\$
    – Simon B
    Feb 16, 2016 at 15:22
  • \$\begingroup\$ @FakeMoustache: I don't change the wiring on the headphone side. I have a mono audio signal and wired it to a stereo TRS socket, where I plug my headphones. \$\endgroup\$
    – ensonic
    Feb 16, 2016 at 16:10
  • \$\begingroup\$ @SimonB: will double check the wires (and the trs socket) \$\endgroup\$
    – ensonic
    Feb 16, 2016 at 16:11

1 Answer 1


Try 'shorting' right and left TRS jack channels with resistors in line. It would mostly get rid off impedance mismatch. Some phones will work with your design but some will not like it. Try using 1k to 10k resistors. They shouldn't affect sound.

Here is a very simple and very informative photo of how to do it: enter image description here

  • \$\begingroup\$ Thanks for the suggestion, but I rather not modify the headphone-cable. So far the 'solution' I posted in my last comment seems to do the trick, though I'd love to understand whats going on. \$\endgroup\$
    – ensonic
    Mar 1, 2016 at 16:03
  • \$\begingroup\$ You have an option of making an optional cable OR an even better option: why not do the same trick just not on the plug but on the input jack on the amplifier? :) It would take less than 20 minutes to do the trick and you won't have problems afterwards. I recommend using 2k to 5k resistor. They won't affect sound and you'll certainly get rid off impedance mismatch. \$\endgroup\$
    – Giedrius
    Mar 1, 2016 at 16:35

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