Thanks. Okay, tried it with the 0.1uF capacitor in place trying to use phantom power on the signal line as drawn. Works, but is quieter than when I supply the voltage myself without the capacitor. Since I'm plugging into my SoundBlaster Live instead of the empeg, it's possible that the soundcard doesn't supply phantom power at all.

Still don't know whether this capacitor is changing the frequency response or not?