Electronic – Headset microphone is noisy, but touching speaker wires removes the noise

groundingheadphonesmicrophoneshort-circuit

I'm repairing my simple wired headset which is composed of two little speakers and one microphone. The audio and mic jacks are separate. The speakers work fine. But the microphone is very noisy. As I was playing with wires, I found out that when I touch both ends of the speaker wire, the microphone noise goes away. Short-circuiting the speaker wire alone won't work. I have to literally touch the wires. This is rather bizarre to me. Do you have any idea what should I do?

I have seen this happening in lamps flickering too. The moment I touch the metal body of the lamp holder, the flickering goes away :-/

Best Answer

The braid of the microphone cable may be disconnected at the plug.

The microphone cable braid, when properly grounded, shields the signal wires from electromagnetic interference/noise.

The ungrounded braid would itself pick up the interference/noise and couple it to the signal wires.

The cable connections are to be checked at both ends to confirm the cause.