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Heil PR40 and 6XXX radios


I want to use my Heil PR40 microphone with my Flex 6500. I heard that I might need a pre-amp of some sort. Has that been the experience of anyone here. I here that Flex radio recommends a "TUBE" pre-amp. REALLY? I have a W2IHY 8-band EQ. I am wondering if that would be more appropriate or if the +20 db boost in software would work instead of anything in front of the microphone input to the radio.

Anyone have experience in using a PR40 with a 6XXX radio and what was your experience and outcome?


  • Rick N4RZ
    Rick N4RZ Member ✭✭✭

    I have a friend that runs a 6400M and he recently hooked up a PR40 and sounds just fine. His Mic setting is significantly lower than a few of us who have PR781 microphones meaning he can easily overdrive it without any preamp in line. He runs it with the compressor and the +20db boost both on.

  • WX7Y
    WX7Y Member ✭✭✭✭
    edited October 2020

    Turn off the +20db boost, That is a MIC pre-amp and see if that helps.

    My PR40 has low gain but sounds wonderful, All MIC's are different even the same Model of MIC's or different build's.

    If using it as a balanced MIC or the modular MIC plug could also make some difference as well.

    DON'T just trust that the built in MIC profiles are correct for your voice and your MIC element, this is a common misconception that these are set in stone and I have never used them other then Default for a starting point.

    Also the TX Equalizer can also add gain if the sliders are set above ZERO

  • Brian KA8CNI
    I'm running a 6600 with a PR40 going into the balanced mic input with a EQplus by W2IHY. I find it easier to get the right mic drive level correct with the EQplus and still have plenty mic gain adjustment. Without the EQplus the mic gain would have to be in the 90's with the +20db boost on.
  • Robert KB6QXM
    Robert KB6QXM Member ✭✭

    @Brian KA8CNI Thank you for that comment. Now I will have to contact Julias at W2IHY for the correct cable to interface the PR40 microphone to the EQ. I only have the 8-band EQ and not the companion module. I hope that I do not have to buy the additional module and cabling.

  • David Decoons, wo2x
    David Decoons, wo2x Member, Super Elmer Moderator

    @Robert KB6QXM

    The PR-40 can interface to the W2IHY 8 band EQ using any one of 4 different cables. If you were using the PR-40 previously with the 8 band EQ on a different radio then you already have that cable. The mic end is a three pin XLR and 8 band EQ end can be XLR, 8 pin Foster connector wired for Kenwood, Yaesu, or Icom. If you do not have one of these cables you can order it from Julius or get a 3 pin XLR male to female cable locally.

    I suggest using a 5 pin DIN to XLR or TRS male cable for the 8 band EQ to 6500. Or if you have a 5 pin DIN to 8 pin Foster connector wired for Yaesu, that will also work.

    Dave wo2x

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