Damage possible from powered mic in socket for un-powered mic? [OT]
I have a portable flash-memory recorder which has a mic input.
The input socket has "Plug-In-Power" this provides power to run a suitably-designed unpowered electret mic which is plugged into the socket. If I use one of the older-style electret mics which contains a battery for its own power then would that severely overload the input electronics of the flash recorder? If so then could such an arrangement actually cause damage to those electronic components? Alex [ Basic tech info for Plug-In-Power = www.telinga.com/pipwp.htm ] -- xposted to 4 groups GNKSA max: sci.electronics.components sci.electronics.repair rec.audio.tech alt.engineering.electrical |
Damage possible from powered mic in socket for un-powered mic? [OT]
Alex wrote: I have a portable flash-memory recorder which has a mic input. The input socket has "Plug-In-Power" this provides power to run a suitably-designed unpowered electret mic which is plugged into the socket. If I use one of the older-style electret mics which contains a battery for its own power then would that severely overload the input electronics of the flash recorder? I'm presuming we're talking about a jack plug & socket here? Mono or stereo? The jack plug has a tip and rings for the audio and DC power? Maybe insertion of an unsuitable plug eg the one on your battery powered mic might short the DC? Anything in the instructions/user notes/online manual about that? I wouldn't think that the signal level itself would cause damage. I have used an 1980s Tandy stereo mike (with an new AA cell in the barrel) with a PC sound card and I had to crank the input gain right up compared with the cheapo (unpowered) mike in my webcam, not that that proves anything much Maybe a Google is order for a more specialised forum? |
Damage possible from powered mic in socket for un-powered mic? [OT]
wrote: I looked belatedly at your link. I don't think you'll be damaging anything. |
Damage possible from powered mic in socket for un-powered mic? [OT]
On Sat, 16 Dec 2006 13:47:02 GMT, Alex wrote:
I have a portable flash-memory recorder which has a mic input. The input socket has "Plug-In-Power" this provides power to run a suitably-designed unpowered electret mic which is plugged into the socket. If I use one of the older-style electret mics which contains a battery for its own power then would that severely overload the input electronics of the flash recorder? If so then could such an arrangement actually cause damage to those electronic components? Alex [ Basic tech info for Plug-In-Power = www.telinga.com/pipwp.htm ] Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Damage possible from powered mic in socket for un-powered mic? [OT]
"default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. |
Damage possible from powered mic in socket for un-powered mic? [OT]
On Sat, 16 Dec 2006 19:57:54 GMT, "ian field"
wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? ----== Posted via Newsfeeds.Com - Unlimited-Unrestricted-Secure Usenet News==---- http://www.newsfeeds.com The #1 Newsgroup Service in the World! 120,000+ Newsgroups ----= East and West-Coast Server Farms - Total Privacy via Encryption =---- |
Damage possible from powered mic in socket for un-powered mic? [OT]
"Michael A. Terrell" wrote in message ... default wrote: On Sat, 16 Dec 2006 19:57:54 GMT, "ian field" wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? No, since I don't expect it to work like that when its designed properly. Also, you are applying a reverse voltage to the coupling capacitor if you try this. Since you mention that, if the cap is a tantalum even a small reverse voltage can cause S/C failure - so it could work after all!! |
Damage possible from powered mic in socket for un-powered mic? [OT]
default wrote:
On Sat, 16 Dec 2006 19:57:54 GMT, "ian field" wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? No, since I don't expect it to work like that when its designed properly. Also, you are applying a reverse voltage to the coupling capacitor if you try this. -- Service to my country? Been there, Done that, and I've got my DD214 to prove it. Member of DAV #85. Michael A. Terrell Central Florida |
Damage possible from powered mic in socket for un-powered mic? [OT]
There is a dc blocking capacitor, so no damage will result.
|
Damage possible from powered mic in socket for un-powered mic? [OT]
"Alex" wrote in message
... I have a portable flash-memory recorder which has a mic input. The input socket has "Plug-In-Power" this provides power to run a suitably-designed unpowered electret mic which is plugged into the socket. If I use one of the older-style electret mics which contains a battery for its own power then would that severely overload the input electronics of the flash recorder? If so then could such an arrangement actually cause damage to those electronic components? Alex [ Basic tech info for Plug-In-Power = www.telinga.com/pipwp.htm ] When you have an equipment source that supplies power (phantom power) to an elecret element -- everything is OK. HOWEVER, IF you use other microphone elements (copper wound, magnetic bobbin, dynamic) -- then the DC power must be de-coupled. You use a capacitor to block this DC power. A 1 mFd. non-polar tantalum capacitor in series with microphone lead. You may get by with a .68 or a .47 mFd but anything less (.01, .005 etc) will not pass any speech audio worth listening to). The cap MUST be a non-polar. This will keep the D.C. from getting across the dynamic element while passing the speech audio through the cap into the mic preamp circuitry. http://www.heilsound.com/amateur/harmonics.htm#DC |
Damage possible from powered mic in socket for un-powered mic? [OT]
"ian field" wrote in message
... "Michael A. Terrell" wrote in message ... default wrote: On Sat, 16 Dec 2006 19:57:54 GMT, "ian field" wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? No, since I don't expect it to work like that when its designed properly. Also, you are applying a reverse voltage to the coupling capacitor if you try this. Since you mention that, if the cap is a tantalum even a small reverse voltage can cause S/C failure - so it could work after all!! That is why a non-polar tantalum is used in this application. |
Damage possible from powered mic in socket for un-powered mic? [OT]
"w9gb" wrote in message . .. "ian field" wrote in message ... "Michael A. Terrell" wrote in message ... default wrote: On Sat, 16 Dec 2006 19:57:54 GMT, "ian field" wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? No, since I don't expect it to work like that when its designed properly. Also, you are applying a reverse voltage to the coupling capacitor if you try this. Since you mention that, if the cap is a tantalum even a small reverse voltage can cause S/C failure - so it could work after all!! That is why a non-polar tantalum is used in this application. Didn't know such things exist! - got a pdf? |
Damage possible from powered mic in socket for un-powered mic? [OT]
"ian field" wrote in message
... "w9gb" wrote in message . .. "ian field" wrote in message ... "Michael A. Terrell" wrote in message ... default wrote: On Sat, 16 Dec 2006 19:57:54 GMT, "ian field" wrote: "default" wrote in message Try it with no battery installed. There is usually just an FET and pull up resistor in it. Removing the battery should leave just the FET and you'd have the pull up resistor/voltage source inside the flash recorder - the way standard un powered electrets work. Doubtful - the output of the OP's powered mic appears to be capacitor coupled, so there's no DC path to supply the FET. Well, cap coupled wouldn't work. I'd try it, nothing to lose, and wouldn't you feel stupid if you didn't try that first? No, since I don't expect it to work like that when its designed properly. Also, you are applying a reverse voltage to the coupling capacitor if you try this. Since you mention that, if the cap is a tantalum even a small reverse voltage can cause S/C failure - so it could work after all!! That is why a non-polar tantalum is used in this application. Didn't know such things exist! - got a pdf? GOOGLE is your Friend for Internet look-ups ! Non polar tantalum capacitor - US Patent 5777840 http://www.patentstorm.us/patents/57...scription.html Data sheets http://www.digchip.com/datasheets/pa...parts_st41.php Vishay http://www.datasheetcatalog.com/data...f/T/C/TC.shtml Kemet FAQ http://www.kemet.com/kemet/web/homep...itor+Selection You can read it straight from Bob Heil (and yes he installs and sells these with this products) A non-polar electrolytic, if available, could also be used. IF you use other microphone elements (copper wound, magnetic bobbin, dynamic) -- on a "phantom powered" device --- then the DC power must be de-coupled. You use a capacitor to block this DC power. A 1 mFd. non-polar tantalum capacitor in series with microphone lead. You may get by with a .68 or a .47 mFd but anything less (.01, .005 etc) will not pass any speech audio worth listening to). The cap MUST be a non-polar. This will keep the D.C. from getting across the dynamic element while passing the speech audio through the cap into the mic preamp circuitry. http://www.heilsound.com/amateur/harmonics.htm#DC |
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