Brice Hughes

3 Channel Bag. Used on boom and 2 wireless days, but with the ability to expand up to 4 wireless on the fly.

In any event, the pinout doesn't seem to be the culprit. It's wired the way Lectrosonics recommends for a 2 wire positive bias lav. The diagram in the servo bias wiring PDF is the same as the one in my UM200's manual. I metered the voltage on the Tram power supply and found that the 5 volts bias voltage is directly on pin 3. In Lectro transmitters, the bias is on pin 2. The mic has pin 2 jumpered to pin 4, and if I'm reading the input cirtuit digram of the UM200C right, pin 4 is connected to pin 3 inside the transmitter with a 1k resister. I've got 3 sets of UM200C/UCR210D that have this problem with both TR50 lavs, so I don't think it's a compontent problem, unless all of them have the same problem. I know I can't be the only guy using a positive bias TR50 with a UM200C. Is anyone else having this problem? Is it working fine for all of you?

That document was the first place I looked, but somehow I missed the part where it said the depicted wiring was for both older and newer transmitters. You're right it sure does seem dumb. I'm gonna go wipe the egg off my face now.

I've got some new Tram TR50 lavs that I've just started using with some older Lectrosonics Tx's and Rx's. They sounded fine (well... like every other Tram) when I was using them hardwired with the power supply. I've tried them a couple of times with my UM200C transmitters, and they are very noisy and require the gain on the transmitter to be turned up almost all the way to light the -20 LED. Are TR50's one of the mics that they changed the wiring scheme for servo-biased transmitters? And if so, how should they be wired to work with my older transmitters?