Audio mixer. I have 4 cm between the transformer and the summing
network - no way to change the layout. Would a 3 mm steel case around
the transformer help much?
Samuel
Probably not even 2:1. Thin sheet steel is fairly transparent to 60 Hz
mag fields. Use a torroidal transformer and keep any loops in the
mixer circuit down to minumum area, and keep the loops in the plane
that has minimum coupling to the transformer, if you can determine
that. Test the transformer to see if it leaks more at some point (like
at the wire terminations) and orient that away from the tender stuff.
You may need a grounded electrostatic shield - aluminum or copper will
work fine, aluminum foil tape even - to kill capacitive hum pickup at
these short distances.
If this is line level stuff, you shouldn't have much trouble from
magnetic coupling out of a torroid.
John