[sdiy] Semi-OT: phantom-powered balanced line driver?

[Ingo Debus]

Hi,

I've bought a nice little electret condenser microphone (for my  
flute). The mic itself is connected to a belt pack with a one- 
transistor preamplifier and a 9V block battery. The belt pack is in  
an unshielded plastic case and a mono phone jack, and thus quite  
sensible to noise and hum pickup. An ideal solution would be a  
shielded case and a balanced XLR output. It would also be nice if the  
thing could be phantom-powered to get rid of the battery.

Now, how do I get a balanced output? SSM2141? The datasheet of the  
SSM2141 says passive circuitry in series with the outputs should be  
avoided, but I need of course series caps to block the phantom power  
voltage. Is the SSM2141 still a good choice or should I rather use a  
good old transformer?

Ingo