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Can I use a TRRS headphone cable in the 6400M headphone TRS jack?

Mike N2YBB
Mike N2YBB Member
edited August 2020 in SmartSDR for Windows
The BOSE QC25 comes with a 4 gang TRRS cable.  The 6400M asks for a 3 gang TRS jack.  The manual clearly states not to use a 2 gang mono plug. 

Does that apply to this situation as well, or can I use the TRRS cable and simply lose the mic?

Tnx es 73 de Mike N2YBB


  • Brian Denley  KB1VBF
    Brian Denley KB1VBF Member ✭✭
    edited March 2020
    I would avoid it and see if Bose has an adaptor to convert to TRS.  I say that only because there are several wirings for TRRS that have the ground in different locations.  Unless another Flex owner has already tried it.  Anyone?
  • henrylance
    henrylance Member ✭✭
    edited March 2020
    I agree

  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2020
    TRRS will not work.  That is for phones and tablets.  You will need an adapter to split out the headphones and mic and connect that to the appropriate 1.8" TRS connectors on the back of the radio.
  • Chris WX7V
    Chris WX7V Member ✭✭

    Tim - I believe this should work, right? Its TRRS to TRS. I'd expect the back of the 6400M would accept the Phone and MIC.


  • Chris WX7V
    Chris WX7V Member ✭✭
    edited May 2021

    I can confirm this aftermarket MIC boom works with my Bose QC25. The package also includes the TRRS splitter to separate out the MIC and PHONEs.

    Even then you can’t just plug in the MIC into the back of the Flexradio, you have to enable BIAS and wire your own TRS adapter for the MIC into the back of the Flexradio using this circuit published by Dale K4DG. When you solder make sure TIP from the radio connected to TIP and RING on the MIC, and short RING/SLEEVE from the radio to sleeve on the MIC:

    Dales original post has a lot of good detail. The circuit also works with the KOSS SB45 headset with integrated MIC boom.


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