"Matti Adolfsen"


To get the best possible noise figure from a mic preamp, you must match
the amp input impedance to the microphone.


** Absolutely FALSE !!!

The best signal to noise ratio is obtained when the mic impedance is MUCH
less that the load impedance. This allows the mic to generate the greatest
signal voltage at the input while noise is a function of actual mic
impedance in the audio band.



This is 600 ohms in most cases.


** Crapology.

The vast majority of *dynamic* mics are of 250 ohms or less impedance.

Condenser mics generate their own noise - far more than the vast majority
of mic pres do - so it rarely matters what impedance they are, far as
noise performance goes.




......... Phil