[ARC5] Carbon mic pops

[J Mcvey]

All of those carbon mike circuits were very similar in design back then. I have never encountered one that "popped" as you describe.This makes me wonder if there was some unknown mod done to the mike or the preamp circuit. I've seen some sites where they replace the carbon element with electretmike elements. I don't know how well that works- maybe its fine, but I always used carbon types with no problems.
Try engaging the PTT without the mike in circuit to see if you still get the noise. it could be from some other source further down the chain...
 

    On Monday, November 28, 2016 10:17 PM, "hwhall at compuserve.com" <hwhall at compuserve.com> wrote:
 

 All the caps were replaced before we powered up. The "battery" DC power supply is quiet, no hum with the PTT held down. Just a loud pop when the PTT contacts close. 
 Wayne
 
-----Original Message-----
From: J Mcvey <ac2eu at yahoo.com>
To: hwhall <hwhall at compuserve.com>; arc5 <arc5 at mailman.qth.net>; milsurplus <milsurplus at mailman.qth.net>
Sent: Mon, Nov 28, 2016 8:03 pm
Subject: Re: [ARC5] Carbon mic pops

My guess is that you have an open cap in the Mic DC filter circuit. 
 

    On Monday, November 28, 2016 9:53 PM, "hwhall at compuserve.com" <hwhall at compuserve.com> wrote:
 

 I have a question about use of carbon mics in circuits like interphones. Mics like the T-17 leave the mic "battery" current circuit open until the PTT is pressed to speak. But the contact closure creates a huge pop in the headphones attached to the amp output. Does anyone know how this was dealt with or did they just live with the earsplitting pops??

Wayne
WB4OGM

______________________________________________________________
ARC5 mailing list
Home: http://mailman.qth.net/mailman/listinfo/arc5
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:ARC5 at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html

   

   
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20161129/a2dcad3c/attachment-0001.html>