[amsat-bb] Re: Pin assignments on a stereo mic input?

George Henry ka3hsw at att.net
Thu Jul 28 19:22:08 PDT 2011

Standard 3.5mm stereo connector wiring is: shell is ground, tip is left channel, 
and ring is right channel.  

What kind of mic are you using?  If it is a condenser mic, make sure that the 
recorder is providing bias voltage on BOTH tip and ring of the mic jack.  Test 
it by plugging the mic into each input jack of the splitter, without the radio 
cable plugged in.  Also, some recorders have a "line/mic" switch to select the 
input level, and if set to line, will probably not supply bias voltage on the 
mic jack.

George, KA3HSW

----- Original Message ----
> From: Bill Acito W1PA <w1pa at hotmail.com>
> To: amsat-bb at amsat.org
> Sent: Thu, July 28, 2011 4:55:49 PM
> Subject: [amsat-bb] Pin assignments on a stereo mic input?
> One more for today...  I am using a stereo digital recorder for logging. It 
> has a stereo 3.5mm mic socket.
> I am using a "attenuating" patch cable from the HT audio into a "stereo 
> splitter" plugged into the mic input
> (it has a stereo plug, and two mono sockets ---  tip and base, and ring and 
> base). The other side of
> the splitter has a mic.  So the intent it to put the HT into one channel, 
> and the external mic (recording me)
> into the other channel, when recording.
> I am only hearing the HT audio on playback. I have a feeling that the plug 
> "base" connection is not ground --
> it is on the ring or tip.
> Any one have or know the signal assignment on a recorder mic jack?  base, 
> ring , and tip?  I would assume
> it would also match the assignment of the mic input of a PC (if you know 
> that)?
> Bill
> W1PA

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