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How To Attach a Mixer (audio) to Balance Input of my 6600M Question

Kevin Mitchell
Kevin Mitchell Member
I have just brought a 6600M from Hamvention. A totally new radio brand for me.
In my previous setup, with an IC-7700, I ran audio from a Heil PR-40 into a audio Mixer into the rear of the 7700. I like the quality of the input audio. I do know in this case, it's Bal to unbal, which I was able to pad and isolate to make usable. No hardwire connection between mixer and radio.
I wish to be able to do this with the 6600M, and I believe it is straight forward, but I wish to pass this over the group to see and get views from those of you that have already done this.
Any advice, suggestions will be gratefully received.
Regards Kevin.


  • Ray Sylvester
    Ray Sylvester Member
    edited July 2019
    guitar center sells a direct box that will do what you want for 29.00  
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited July 2019
    I can't remember, does the 6600 have an line in option in the mic input menue? If it does then just run a cable from the mixer to the mic plug and use line in.
  • Condy Alley NI4Z
    Condy Alley NI4Z Member ✭✭
    edited July 2019
    Why add an external device when Smart SDR has both TX and RX equalizers built in? I use the plastic FHM-2 and get great audio reports. Seems like adding complexity.
  • WX7Y
    WX7Y Member ✭✭✭✭
    edited June 2020
    The 6600M has a 600 Ohm Balanced input on the back of the radio, just plug it in, I run my PR-40 with NO external mixer box and then set the settings on the internal Equalizer and ALWAYS have great audio reports, Then create a profile for your settings for this MIC settings,   If I have another MIC I would plug it into the 1/8" jack and switch in the radio between the Balanced and MIC and set a new profile for that MIC. 
    The only thing I would use a external mixer for is if you have many  Mic's that you want to use but to each there own that's why it's called the FLEX.


  • K0FLY
    K0FLY Member ✭✭✭
    edited July 2019
    The 6600 as well as all of the Flex 6x00 radios have a 15 pin Cannon D connector on the rear panel (Accessory Connector)..  Pin 1 of that connector is "LINE IN" (-10 dBV level).   You should be able to select "LINE IN " for the mic input and present mic audio to that connector.  I assume that its 600 ohms.  A "Beta Tester" here in Cedar Rapids uses this setup

    The Hardware Manual is down loadable from the Flex site, the pin  description  is on page 23 of the 6400/6600 version.

    Gayle K0FLY
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited July 2019
    Kevin, keep in mind you have much more control of the audio on the Flex then you have on an Icom. I really do not see any advantage in an mixer other than the need to use many mics.
  • Warren-K6WKW
    Warren-K6WKW Member
    edited July 2019
    This cable should do the trick for you. Just use it from the mixer to the radio's balanced input.
    Warren - K6WKW
  • Mike VE3CKO
    Mike VE3CKO Member ✭✭✭
    edited July 2019
    Yes you would get good audio reports but with a PR-40 you would get better audio reports :) Also some people like me don't like holding onto a hand mic, as I multi-task when on the radio, a hand-held is just not for me.
  • wa4wab
    wa4wab Member ✭✭
    edited July 2019

    Same kind of cable listed above was used here.

    This is how I did it on my 6400m, though I used a 3.5mm/ 1/8" right angle TRS directly into the mic input in back. Combo is the Radio - TSR/XLR cable - ART tube MP pre - XLR/XLR cable - Marshall MLX-990. In your case put your mixer in place of the pre-amp.

  • Mark_WS7M
    Mark_WS7M Member ✭✭✭
    edited July 2019
    Just to add some color:

    I have an Audix recording Mic.  I ran it into a pre-amp, then into a DAQ Ultra Curve then balanced into the 6600.  

    With this setup I can get the audio to sound exactly how I want.  The DAQ device allows super fine equalization, far more than the Flex EQ which I left flat.

    This was a lot of cables, a lot of setup and just to get on SSB (which is rare for me) the power up of a few more devices.  It worked well and I got fantastic audio reports.

    For Christmas a year ago my wife bought me a Rode NT USB mic which is designed for podcasters.

    I plugged this into my PC, used the Flex EQ and got audio reports ALMOST as good as the complex balanced setup.

    Also, on some bands I would get a little RFI into the balanced setup due to long wires and perhaps other reasons.  When I switched to the USB Rode mic the RFI disappeared.

    One big downside that I don't agree with is when using PC as the audio source the footswitch input for keying the flex DOES NOT connect the audio.  I think this is a major flaw.  You have to use the MOX button on SSDR or get fancy and wire up a PTT of some kind.

    In some other forum entry Tim from Flex described why this was done but I still don't agree with it.  The footswitch PTT input on the Flex should simply do exactly what it does.  Key the radio and take in any audio source that is currently selected.

    So my point of posting is that you can get great audio from some of the USB mics out there and you might keep your setup a little simpler.  Like me, however you might have to deal with the MOX issue.

    FRStacks can help, you can also wire up a CAT keying cable, etc.   Just feels like we should not have to do that.

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