I am confused about loading a dynamic or ribbon mic on the way into a preamp circuit. Everything I've read (and Ohm's law) says that the higher the load impedance the less loss there will be due to loading. So why aren't all preamps designed to terminate a mic with 1 meg and be done with it? What is the downside of using too high a value of load resistor? Also (n00b question) what is the difference between a resistor to ground on each side of a balanced mic, and a single resistor across a mic?
I have read Richard Werner's AES paper from 1955 dealing with ribbon mics.
I am building this circuit (figure 2) using the THAT 1512 IC:
http://www.thatcorp.com/datashts/1500data.pdf
They use a 1K resistor on each side of the mic input to keep noise down. I've tried resistors all the way up to 5K on each side (10K combined) and do not see a change in the noise floor.
I have read Richard Werner's AES paper from 1955 dealing with ribbon mics.
I am building this circuit (figure 2) using the THAT 1512 IC:
http://www.thatcorp.com/datashts/1500data.pdf
They use a 1K resistor on each side of the mic input to keep noise down. I've tried resistors all the way up to 5K on each side (10K combined) and do not see a change in the noise floor.