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Very Low Noise Balanced Microphone Preamplifier Circuit

This circuit is similar to to the professional grade microphone preamplifier that are used in commercial-grade audio mixing desks, according to the commentary. Features very low noise, balance input and high gain.

Screenshot: Very Low Noise Balanced Microphone Preamplifier Circuit

This amplifier circuit is designed to have noise levels close to that of the theoretical minimum. It features balanced microphone input, variable hi-gain and high hum rejection, meaning that it's pretty sweet!

The circuit uses a transistor compound pair of 2N4403's and BC549's, which provides for a more linear response. It then uses a TL071 op-amp circuit in order to facilitate the differential (balance) input.

This mic preamp operates at 15 Volts DC - and the power supply should be very regulated and smoothed for optimum results. The circuit does however feature and small DC smoothing filter (C4/R14), which will help smooth small ripples on the DC supply.

 
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COMMENTS
aliasgharalavi says: (April 28 2008, 7:45am)

Thank you

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