On Sat, Jan 12, 2013 at 12:45 PM, Brian Lloyd <[email protected]> wrote:
On Saturday, January 12, 2013, Howard Z wrote: > Hi, > > I ordered parts for a simple circuit to connect my Flightcom 4dlx > microphone to my radios. I found a few circuits to choose from, and > selected the one a friend has used for years with her flightcom headset. > The schematic originally came from Davis Clark which is very simple using > only two capacitors and one resistor. My aviation headset adaptor only requires a single resistor for the flex 5000 to go between the bias supply and the mic pin. The input already has a coupling capacitor. > > My Kenwood TS-590 microphone jack provides 8 Volts which is just enough as > flightcom specs say the microphone needs 8 to 16 volts. The Flightcom will work on the 5v bias supply just fine. I have done it. In fact I have used the 5V bias on David Clark, FlightCom, Bose, and Avcomm. (FWIW, the Avcomm headsets have the best noise-canceling mics I have run across.) > My Flex5000 microphone jack only provides 5 volts which is inadequate. 5v is adequate. It works fine. Just use a smaller bias resistor. I used 200 ohms. It just means lower output but you only need dynamic mic level output anyway, not carbon mic level output. The smaller bias resistor will have less drop and will bring the operating voltage up to where it needs to be. > > One solution is a 9 volt battery. Another solution is to run wires to my > power supply. > > Is there a safe and not very complex mod to the Flex5000 microphone jack > to provide 8 to 16 volts? You don't need it. Try it with the 5v bias supply. You will find it works fine. -- Brian Lloyd, WB6RQN/J79BPL 3191 Western Dr. Cameron Park, CA 95682 [email protected] +1.767.617.1365 (Dominica) +1.916.877.5067 (USA) _______________________________________________ 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 innovation and other technical SDR topics.
