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Original question:
Dear TI-san,
I decided to use a microphone"A" with an output impedance of 5.2kΩ and set resistance of the amplifier input to 8.2kΩ.
8.2kΩ is intended to minimize power supply noise of connected laptop computer.
After that, I changed from ｍicrophone"Ａ" to ｍicrophone"B", so I was allowed to discuss change of op amp peripheral circuit with E2E.
And I understand that 8.2kΩ of microphone amplifier input resistance was obtained with consent TI-san.
The manufacturer of ｍicrophone"B" insists on changing input resistance of microphone amplifier from 8.2kΩ to 82kΩ, which is 10 times larger.
The rationale is that output impedance of ｍicrophone"B" is 5.5kΩ.
Please let us know your opinion.
Thanks,
S.Suzuki
Hi Shinya,
microphones are usually connected to the amplifier by performing "voltage matching" (don't know whether this is the right term in Englisch 
) where the load resistance is at least five times (better ten times) the source resistance of microphone. So the manufacturer may be right.
Kai
