On 5/30/10 3:18 PM, William H. Fite wrote: > When I was flying my choice was David Clark but I know Flightcom is > good--and a lot cheaper. Did you build a box to match impedance? Or does > someone make a box? > You know, I got that wrong. It isn't Flightcom (although I have one of those too) but Avcomm is the one that has the great noise-canceling mic. The headset I am using is the Avcomm AC-200pnr. List price is $134 but street price seems to be about $115.
I also have the Avcomm AC900pnr which is more comfortable for long term wearing but the street price is about $220. http://www.avcomm.com/index.php?route=product/category&path=35_36 As for matching things up, I just plugged the headphone in. It works acceptably well. Audio quality is excellent. The impedance of the earspeakers is 300 ohms per earspeaker so they present no difficult load for the headphone amp. There is adequate drive to make the headphone play as loud as I am likely to want. If you need more gain a speaker-to-line level transformer or outboard amp might be in order. I didn't find it necessary. For the mic I made a cable to go from the 8-pin mic connector on the front of the 5000 to go to a standard in-line aircraft mic connector. I use bias from the +5V on pin 2 through a 220 ohm resistor to Mic+ (pin 8). The mic input (pin 8) is capacitor coupled internally so I don't need a coupling cap to keep the mic bias out of the input stage. I don't use PTT with the headset but I did connect it to the tip of the in-line mic jack so if the headset has PTT it will work. (Some of the Avcomm headsets have a PTT button on one of the earcups.) Normally I use VOX or a foot pedal. The nice thing about these headsets is that they are constructed much more robustly than almost any consumer headset. They have heavy-duty earcups, metal head-band, etc. YMMV. -- 73 de Brian, WB6RQN/J79BPL _______________________________________________ FlexRadio Systems Mailing List [email protected] http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archives: http://www.mail-archive.com/flexradio%40flex-radio.biz/ Knowledge Base: http://kc.flex-radio.com/ Homepage: http://www.flex-radio.com/
