On Sat, 3 Jul 2004 15:07:57 +1000, "Phil Allison"
wrote:

** A voltage injected into a balanced audio line by external magnetic
fields ( like nearby high AC current cables and transformers) creates a hum
signal in differential mode that the pre-amp *will* amplify - its CMRR has
no effect.

And, by the way, before you go "correcting" someone like Mike
Rivers, who's a real engineer as evidenced by the depth and
clarity of his thinking, you might get the most basic stuff
straight.

For a beginning to a clue, think about the wavelength of a
hum field.

A man apologizes when he's wrong. Deal.

Chris Hornbeck