Believe it or not resistors do add noise to a circuit. I worked with a fellow that designed anti-submarine warefare equipment for the defense department. He was explaining to me how poor quality resistors created noise in the listening cicuits.
If you look deeply into the specs of metal film resistors you'll find noise specs. In the case of a carbon film resistor I understand it to be the way the carbon reacts to the current traveling through it.
For the rest of us we'd never notice it or hear it or probably be able to measure it with the off the shelf equipment available.
There we all learned something new today...
RSlater,
RSmike
