I've acquired some clearcom phone handsets (not actual clearcom brand ones but absolutely identical), I soldered the ends on myself and everything works fine except for a buzzing sound when the push to talk button is not pressed in. Once pressed, the push to talk button seems to stop the buzzing. Also, when you touch the connector it stops buzzing. I've tried bridging the microphone ground (pin 1) to the screen on the connector but it still buzzes. Surely it can't be the speaker ground I have to solder to the connector? I can't connect the grounds of the speaker and mic together as obviously they have to be separate. Any ideas for a solution? It's so unusual and it's definitely not the pack, it's 100% the handset.