I'm sure that a solution using integrated balanced front end amplifiers, as
many people suggest, is a low development and construction pain route, but
it is unlikley to be as cheap as less integrtaed alternatives. There are
vast numbers of op-amp based differential amplifier solutions out there. An
utterly superb place to look for application notes for all things analog is
Linear technolgies app note library.

Publications generally

        http://www.linear.com/pub/

Application notes

    http://www.linear.com/pub/doc_group.html?pub_type=app

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Misc app notes of variable usefulness


Analog Devices SSM2135 dual single supply audio opamp
Available digikey. Not overly cheap.
Some good ideas in data sheet though.


http://www.analog.com/UploadedFiles/Data_Sheets/527742802SSM2135_0.pdf

AD AN115 - balanced low noise microphone amplifier design.
Cheating again !!!! :-)
Sounds to be exactly what you want EXECPT not single supply as shown.

    http://www.datasheetarchive.com/cgi-bin/q.php?pi=2261


http://212.57.231.17/datasheetarchive/Datasheets/AnalogDevices/DS5634.pdf

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Large number of audio amplifier ccts
Most (?all) the below came via here)

        http://www.discovercircuits.com/A/a-audioamp.htm

Low noise balanced microphone preamp - split supply

        http://sound.westhost.com/project66.htm


Totally OTT FEt preamp just for interesty - +/-24v !

        http://www.borbelyaudio.com/index32.htm


How the professionals do it.
They cheat ! :-) - INA163 front end !!!

        http://www.rane.com/pdf/ms1bsch.pdf

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