Scott Hersha
Well Known Member
Here's a question for those of you that have the single LEMO plug for your headset (Bose, or Lightspeed). When I upgraded my panel last summer I must have done something different because since then I have had a lot of trouble with noise in my headset. The wiring harness for the panel mounted plug has 26 awg shield wires that are supposed to be connected to existing audio shields or to an audio ground. I discovered that I had connected both ends of the LEMO shields to the mic lo and phone lo to my audio panel (PAR 100EX), which is synonymous with the barrel ground on a standard headset plug. This was wrong, so I disconnected one end of this shield. That didn't help at all. Last night I disconnected the remaining LEMO shield from the audio panel mic/phone lo and went straight to my audio ground buss bar. I haven't tried it since this change, but I thought I would ask the experts here how they wired their LEMO's.
Also, I changed my +12V power input from the main bus to the audio system bus power. I don't think that will have any effect, but that was where the power came from before the upgrade. At one point I was frustrated and disconnected the power wires in flight and went to batteries on my A20. It got very quiet and worked perfectly on battery. I know it seems like its a noisy power problem, not a grounding problem, but it seems like a grounding/shield problem because of the occasional popping noise I hear - like a static discharge. So - audio experts please help.
Thanks
Also, I changed my +12V power input from the main bus to the audio system bus power. I don't think that will have any effect, but that was where the power came from before the upgrade. At one point I was frustrated and disconnected the power wires in flight and went to batteries on my A20. It got very quiet and worked perfectly on battery. I know it seems like its a noisy power problem, not a grounding problem, but it seems like a grounding/shield problem because of the occasional popping noise I hear - like a static discharge. So - audio experts please help.
Thanks