While on set the other day, I had something very perplexing happen. I was using my brand spankin' new COS-11D with a Senny G3 set I had recently picked up on the used market. After about 11hrs of uneventful use, I set down my bag, powering off the mixer and recorder(302 &702). When I came back about 10min later and powered everything up(RX and TX remained "on" throughout this power cycle) I found that my lav was significantly quieter. I double and triple checked that nothing had changed with the mixer/recorder, and found nothing out of place. I ended up increasing the sensitivity on the TX and everything was fine for the rest of the shoot.
After doing some research, I came across this on the Sanken website in regards to the "2-wire" wiring method...
"(1) This method can have approx.10dB gain because of FET DRAIN output.
(2) It might have unevenness in output level because of FET gm difference.
It may have a negative phase output signal when it has a positive sound wave."
My questions are...
1. what does the above quote mean exactly? Will a COS-11 in 2-wire mode have a potential to swing 10dB in one way or another?
2. If the answer to 1 has no relation to my issue, has anyone had this happen, or know what might be the culprit?
Thanks in advance for all your help.
Best,
-Travis