XLR phantom power to plug-in power for lavs

[gpforet]

I've got a show coming up where I want to place two lavs in a race car (one to capture the engine sounds, and one attached to the driver). My DR-100 has volunteered to be placed in the car (in a protective case), to serve as the on-board recorder. Since this is dirt track racing, and the mics may well incur damage, dirt, and/or destruction, I'm not planning on using my Trams, but rather, my Oscar Soundtechs.

Here's my problem:
All of my lav mics are wired for sennheiser 3.5mm TRS, to be used with my G3 transmitters. I would like to adapt my OST mics to be powered from either phantom from the DR-100, or a separate battery power supply. I know that Sennheiser makes a phantom to plug-in power adapter but at $150 ea. (I need two), that seems excessive for what I'm trying to do. I could buy two OSTs configured for phantom for that price.

Anyone have an idea on how I can approach this for, say, about $100 for both mics?

 

[Richard Crowley]

If you have the pin out of your microphones, it doesn't take much to power them from a temporary battery arrangement.

 

[gpforet]

From what I've been able to tell, the ME-2 are positive bias so it should be really easy to put 3v DC across the mic.. Do I need to strip the DC offset with a capacitor before the signal hits the recorder?