AUDIBLE HUM FROM MICROPHONE. https://bfreebandingtalktheplanet.runboard.com/t951 Runboard| AUDIBLE HUM FROM MICROPHONE. en-us Thu, 28 Mar 2024 20:37:45 +0000 Thu, 28 Mar 2024 20:37:45 +0000 https://www.runboard.com/ rssfeeds_managingeditor@runboard.com (Runboard.com RSS feeds managing editor) rssfeeds_webmaster@runboard.com (Runboard.com RSS feeds webmaster) akBBS 60 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7232,from=rss#post7232https://bfreebandingtalktheplanet.runboard.com/p7232,from=rss#post7232Hi Patrick Look for the cablage microphone my friend and test .      Ts 850s and 110c Astatic Micro Blank = 1 Red = 2 emission =Transmiting Reception 6 = Black = Recept Mass = braid 7   Mass TX = blue mass 8 73's Pascal 14FB102. nondisclosed_email@example.com (fb102pascal)Fri, 10 Apr 2009 12:32:40 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7152,from=rss#post7152https://bfreebandingtalktheplanet.runboard.com/p7152,from=rss#post7152Hi John, thanks for the info, I tried the removed microphone element in another mic just to see if it was a dry joint, I'm 100% sure now that the element was damaged as the problem was still there with a massive hum, so that is that sorted. As regards to the wiring for the voltage to supply the amplifier in the mic, I have identified the pin on the TS850s radio that supply's the voltage out but I don't know what wires on the astatic mic to connect to that pin (there are two unused wires on the microphone lead) it has to be one of those or a combination perhaps. Unfortunately I do not understand the schematic diagram of the mic to see what wires are the voltage ones.nondisclosed_email@example.com (mikefox whiskey)Mon, 06 Apr 2009 08:18:34 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7151,from=rss#post7151https://bfreebandingtalktheplanet.runboard.com/p7151,from=rss#post7151Patrick test all the radio pins from ground to each pin in turn on rx, stick a dummy load on and do the same thing but in tx. one pin will go from a float voltage probably about 4v to about 8-9v thats ya power out pin then just trace it back. Hope that helps. All mikes have an equalisation hole in them otherwise they'd blow up like a ballon when the rain comes! did you solder the new element in? it could have been a dry joint that is now OK. Maybe? just a thought Patrick.johnnondisclosed_email@example.com (John193)Mon, 06 Apr 2009 00:13:02 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7148,from=rss#post7148https://bfreebandingtalktheplanet.runboard.com/p7148,from=rss#post7148You could be right Andy, that hole is maybe supposed to be there, if it was though there must of been a problem inside the diaphram itself maybe? I don't know enough about microphones to know what is even in there, anyway replacing that diaphram with another one (though slightly different) has cured the problem. I don't know if I have another problem now, but when I am transmitting after about 20 minutes I think I can here RF in the headphones and a roughness on the audio, I seriously don't know if it's real or in my head! I have been working too hard recently! I wonder could it be the 9v battery though I've tried a few. I wish I could find out what wires to use to take the power for the microphone from the radio and do away with the need for a battery.nondisclosed_email@example.com (mikefox whiskey)Sun, 05 Apr 2009 23:07:10 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7147,from=rss#post7147https://bfreebandingtalktheplanet.runboard.com/p7147,from=rss#post7147You could be right Andy, that hole is maybe supposed to be there, if it was though there must of been a problem inside the diaphram itself maybe? I don't know enough about microphones to know what is even in there, anyway replacing that diaphram with another one (though slightly different) has cured the problem. I don't know if I have another problem now, but when I am transmitting after about 20 minutes I think I can here RF in the headphones and a roughness on the audio, I seriously don't know if it's real or in my head! I have been working too hard recently! I wonder could it be the 9v battery though I've tried a few. I wish I could find out what wires to use to take the power for the microphone from the radio and do away with the need for a battery.nondisclosed_email@example.com (mikefox whiskey)Sun, 05 Apr 2009 23:06:57 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p7146,from=rss#post7146https://bfreebandingtalktheplanet.runboard.com/p7146,from=rss#post7146Glad it's cured, but that pin prick hole may be there to allow atmospheric presure equalisation if it was in the actual diaphram - it may not have been the fault.nondisclosed_email@example.com (Hot Fusion)Sun, 05 Apr 2009 19:16:08 +0000 Re: AUDIBLE HUM FROM MICROPHONE CURED!https://bfreebandingtalktheplanet.runboard.com/p7140,from=rss#post7140https://bfreebandingtalktheplanet.runboard.com/p7140,from=rss#post7140The audible hum from my Astatic 1104c desk mike is now cured, HOORAY! it turned out that there was a pin prick hole in the microphone's ceramic element (how it got there I don't know) I have replaced that element with one from my Astatic 575 m6 microphone and all is working now. Thanks for all the suggestions.nondisclosed_email@example.com (mikefox whiskey)Sun, 05 Apr 2009 17:02:48 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6938,from=rss#post6938https://bfreebandingtalktheplanet.runboard.com/p6938,from=rss#post6938They are across the mic socket in rig Patrick they help present the right load to the audio amp, Different impedance mics need different values ideally, normally the manufacturer fits a middle of the road 100n in there but some mics need less power mics normally need more. Bye the way is the hum 50hz mains by any chance? john193 nondisclosed_email@example.com (John193)Thu, 26 Mar 2009 20:14:26 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6892,from=rss#post6892https://bfreebandingtalktheplanet.runboard.com/p6892,from=rss#post6892quote:John193 wrote: are the decoupling ceramic disc caps in good elec contact with ground? John fb193 Hi John, thanks for the reply, I tested all the wires and the screen with a multi meter and they seem fine. Where in the microphone do I find the decoupling ceramic disc caps you mentioned? Thanks nondisclosed_email@example.com (mikefox whiskey)Wed, 25 Mar 2009 18:40:19 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6859,from=rss#post6859https://bfreebandingtalktheplanet.runboard.com/p6859,from=rss#post6859Patrick have you tried combining the un-used leads and attaching them to the radio ground ie the case, it could be harmonic length? is the screen intact? are the decoupling ceramic disc caps in good elec contact with ground? Other than that Dunno! John fb193nondisclosed_email@example.com (John193)Tue, 24 Mar 2009 16:00:50 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6612,from=rss#post6612https://bfreebandingtalktheplanet.runboard.com/p6612,from=rss#post6612Hi Dave and Andy, Thanks for your replies, I have tried what you suggested and checked the earth wire and the other wires in the lead and it seems to all be fine, the problem is still there, is it possible that a resistor or diode inside the amplifier circuit in the mic be broke? I dunno, maybe there is another wiring configuration I can use? This is how the wiring is: Astatic 1104c Microphone (all astatic mics have these colours) White - Audio Shield - Ground Red - TX Control Blue - Switching/Common Black - Receive Control ? Yellow - ? Kenwood TS850s (8 pin plug) Pin 1 - Mic Pin 2 - Stby pin 3 - Down Pin 4 - Up Pin 5 - 8V/approx 10mA Pin 6 - NC Pin 7 - GND (Mic) Pin 8 - GND (Stby) Now this is the way I have the 1104c mic wired to the TS850s: White - Pin 1 Shield - Pin 7 Red - Pin 2 Blue - Pin 8 Black - not connected yellow - not connected I don't know if this wiring code makes any sense or any help to anybody, but I thought I would put it on anyway. Perhaps I will get in touch with the seller (eBay) though there was no returns stated on the mic listing. On another point, I have an Astatic 575-M6 mike with the same wiring, from the info I have given could somebody tell me how to wire the mic up to take the power from the Kenwood transceiver and not the internal 9V battery in the mic? Thanks. nondisclosed_email@example.com (mikefox whiskey)Thu, 12 Mar 2009 19:25:04 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6584,from=rss#post6584https://bfreebandingtalktheplanet.runboard.com/p6584,from=rss#post6584I'm not familiar with the wiring on this setup, but it sounds to me as though the case of the microphone isn't earthed. You can check this by holding a wire between the metal of the mic and metal on the rig - the hum should disappear. If it does, you need to identify the earth on the mic lead, and make sure it is connected to the earth on the rig. Do you get any RF feedback? This can happen if the case of the mic isn't earthed and screening it properly.nondisclosed_email@example.com (Hot Fusion)Wed, 11 Mar 2009 22:24:48 +0000 Re: AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6583,from=rss#post6583https://bfreebandingtalktheplanet.runboard.com/p6583,from=rss#post6583Hi Pat, I know this sounds obvious, but are you absolutely sure there is no shorting across the terminals? And GRD and earth are two different pins, so Shield and BLK (earth) are not wound together , this is from memory Pat and I think pin 8 is blk and shield is common (Casing). Sorry if that doesnt help nondisclosed_email@example.com (yamanx1)Wed, 11 Mar 2009 22:13:01 +0000 AUDIBLE HUM FROM MICROPHONE.https://bfreebandingtalktheplanet.runboard.com/p6582,from=rss#post6582https://bfreebandingtalktheplanet.runboard.com/p6582,from=rss#post6582I wonder if anybody can help, I have an Astatic 1104c base microphone which I have just wired to my Kenwood TS850s, when I transmit audio there is a loud hum on my speech, when I touch the metal base of the mic or the shield of the mic cable when opened the hum goes down quite a bit but is still audible, through the monitor I can here that the mike is making an electronic clipping sound too. I have followed the same wiring diagram as other astatic mics I have. Has anybody any ideas what is wrong or experiences of using astatic mikes and a kenwood TS850s? nondisclosed_email@example.com (mikefox whiskey)Wed, 11 Mar 2009 21:34:48 +0000