Balanced ECM line driver

[marvinkite]

I am trying to create a battery operated balanced front-end for the LME49724 line driver which I will be getting in any day now. Please evaluate my circuit and tell me what I've got wrong. The application is for acoustic guitar range, so the poly caps don't have to be huge (and expensive). Any comments would be very helpful. I want to reduce noise by doubling up the signal voltage by virtue of balanced signal lines using a 'standard' electret, rather than a 'linkwitz mod'. I then plan to compare that with a modded ECM to see which one is better for acoustic guitar.

[KSTR]

you might want to check this out, lots of info on the WM61A (capsule of the ECM, or at least quite close) : John Conover: Using the Panasonic WM61A as a Measurement Microphone

[marvinkite]

Any one want to comment on the circuit? I'm kind of lost on this voltage divider thing. I hope the DC gets cleaned out before the differential inputs. Would it be better having the blocker caps at the IC inputs just before the feedback loops? Anybody???

[marvinkite]

Thanks for the info Conover, I also looked at all of the electrets at JLI Electronics Electret condenser microphone elements models & specifications – JLI Electronics they seem to have a huge supply. However, none of them - including their Panasonic OEM replacements have any of the new FET replacements in them (that I could tell). My guess is they have years of stock still sitting in the warehouse, and no big orders coming in for 'updated' condenser capsules to warrant making any new ones. It would be nice if some manufacturer made a line of 'studio-grade' capsules for high-tech digital headsets etc.