Chosen Solution
I am having trouble identifying something on a pcb. I THINK its ground, but…
It contacts this metal plate (why i think it might be the ground) on the inside of the earbud cover:
Backside of pcb:
The copper plate is likely the external connection to the charging case. You likely have a metal surface on the other side and you likely have a second contact somewhere else as well. Well … There is no means to connect an external mini-plug connection. Each ear bud is mono (each) not stereo within the single bud. You need access to both amps (each bud) to gain the signal and the output is set for a pico ear speaker not strong enough to drive anything without an additional Amp. Bottom line: its just cheaper and easier to just get/build a Amp unit which either has BT as an input (not output) or is directly wired to your music source.
