Thanks to all!
Will try adding a resistor to the circuit tomorrow! Thanks again George K2CM ________________________________ From: William H. Fite [[email protected]] Sent: Monday, July 11, 2011 8:39 PM To: Graham Haddock Cc: George R Allen; [email protected] Subject: Re: [FlexEdge] David Clark H10-76 and and F5K In fact, David Clark does make some headsets with mics that do not require bias. I'm not sure whether they are only special order but they are available. In general, however, you can assume that any aviation headset has what Graham calls a "carbon mike equivalent." Bill (Long-time DC user for both aviation and radio) On Mon, Jul 11, 2011 at 7:42 PM, Graham Haddock <[email protected]<mailto:[email protected]>> wrote: George: Almost all aviation mikes are "carbon mike equivalent" at the connector, and require a bias voltage/current to operate. So, yes it has a dynamic mike as the the audio pickup, but then has a transistor amp following it, and the combination requires power, and expects it to be fed from an approximate ~600 Ohm load/source. So a resistor from mike hi to +5 Volts, typically 560 Ohms (not 100 Ohms) will provide the bias and the approximate 600 Ohms the mike is designed to work against as a load. This is built inside all aviation radios and intercom panels, so David Clark is probably not used to seeing their customers adding resistors externally. --- Graham / KE9H == On Mon, Jul 11, 2011 at 6:34 PM, George R Allen <[email protected]<mailto:[email protected]>>wrote: > I have interfaced my H10-76 to the F5K. > > > > Phones work, mic doesn't. I see the slightest output from the H10-76. > > > > I have had suggestions from this group to put a 100ohm resister from + 5v > to mic+; but, the David Clark web site advises against this stating that the > mic is a dynamic mic. > > > > Any suggestions? > > > > George > > K2CM > _______________________________________________ > Flexedge mailing list > [email protected]<mailto:[email protected]> > http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz > This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used > for posting topics related to SDR software development and experimentalist > who are using beta versions of the software. > _______________________________________________ Flexedge mailing list [email protected]<mailto:[email protected]> http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software. _______________________________________________ Flexedge mailing list [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexedge_flex-radio.biz This is the FlexRadio Systems e-mail Reflector called FlexEdge. It is used for posting topics related to SDR software development and experimentalist who are using beta versions of the software.
