I plan on buying the Behringer MICROMIX MX 400 line mixer because it's really cheap and I don't need more than 4 input channels. The only problem is that it has a mono output. I tried searching for some sort of connector that splits the mono output into 2 1/4 jacks so I can just plug those into the left and right speaker. I can only find 1/4 to 1/8 though, no 1/4 to 1/4. And is there a way to convert the mono output to a single stereo jack to connect to my headphones?

  • Please consider rewording your question, it isn't clear what your headphones have to do with the issue, since headphones don't typically have a pair of 1/4" jacks. Commented Feb 6, 2014 at 23:17
  • 2
    Connecting the headphones has a completely different problem: that output is line-level, with too high impedance too be useful for headphones. Do get something with a headphones output if you need it. There are plenty of mixers with as little as 4 channels, but more otherwise functionality of all kinds. Commented Feb 7, 2014 at 11:02
  • I have the exactly the same mixer, I think the problem the OP is referring to is that the audio only comes out one channel (in my case the left) because the audio is output as mono. I think Gamidron wants to be able to listen to the mono channels in both speakers.
    – Ambo100
    Commented Feb 9, 2014 at 12:34
  • @Ambo100 exactly. How did you fix that problem?
    – Gamidron
    Commented Feb 9, 2014 at 16:03
  • @Gamidron I haven't fixed the problem. I have considered getting a 3.5mm Mono to Stereo Jack Adapter
    – Ambo100
    Commented Feb 9, 2014 at 16:16

2 Answers 2


Monoprice should have everything you need:

AJ Henderson brings up a good issue in the comments: impedance issues can't and won't be addressed by splitters alone.

  • Except this doesn't address any of the multiple possible impedance problems he could run in to. The output from the mixer will not be correct for headphones and it won't be correct for the speakers unless they are powered speakers.
    – AJ Henderson
    Commented Feb 7, 2014 at 18:48
  • Good point - though the question starts by talking about simply splitting a signal and only throws in the headphone angle at the very end. Commented Feb 8, 2014 at 0:38
  • yeah, I just wanted to make sure to note for his benefit that those parts might not be sufficient depending on what he is actually trying to do.
    – AJ Henderson
    Commented Feb 8, 2014 at 0:45
  • If you want to post an answer that addresses the impedance situation, I've got an upvote waiting for you. Commented Feb 8, 2014 at 0:50
  • I decided not to answer this one because the question wasn't clear enough what was being asked. You had already mentioned that and I was waiting for a reword to make it answerable.
    – AJ Henderson
    Commented Feb 8, 2014 at 2:31

There are two answers to your question. Simple answer has been given by ObscureRobot here. I only add to make sure your source already completely summed to mono, otherwise the right channel will be dropped, as explained below.

Alternative answer:

The right channel on all five stereo jacks are connected to literally nothing (a waste if you ask me), but thankfully, since these jacks are indeed stereo we can simply bridge the left and right channels of each jack directly on the circuit board as seen in the photo. Now, the left and right channels of each input are truly summed to mono, and we have a dual-mono main out. We can use something like the Hosa YPP 111 (or if you're really daring, add a pan knob circuit —maybe I'll try that next—and use the Hosa YPP 117) or a typical insert cable (if you can find one long enough) to split the output into two 1/4 mono jacks for use with speakers. Headphones can be plugged directly in, but you shouldn't do this. Rather use a headphone amp.

Tested and works flawlessly.

I don't see why Behringer didn't do this themselves.

Reminder: Keep in mind, the output jack isn't a headphone jack, it's a line out. As mentioned in other comments, you might not get an accurate audio reference and may even damage your headphones or your hearing when plugging cans into this jack.

PS, I think the original question is pretty clear.

Behringer MX400 Stereo Mod

  • Such a beautiful solution thank you. I will solder mine right now. Is it fine to plug my headphones in if they are powered headphones? And will this produce a lower signal through left and right (since electricity is shared between them now) compared to Mono?
    – sloth
    Commented Jan 11, 2021 at 23:40
  • I can confirm that this works for me: i.sstatic.net/csTfz.jpgs , now I'm curious how did you know that "The right channel on all five stereo jacks are connected to literally nothing" Commented Nov 5, 2021 at 9:58
  • I can also confirm that this works. I tried it myself this morning and now have stereo audio coming out of the mixer.
    – Shadowvail
    Commented Dec 4, 2022 at 17:32

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