best method to minimize electromagnetic induction

[pone tony]

I'm a newbie on this forum, so please bear with me and remember: there are no such things as stupid questions, just stupid people.

I think I have a fairly good grasp of how to minimize hum that results through shared ground loops. I've also seen pictures of "good" layouts where the filament wires are tightly wound around each other to cancel out electromagnetically induced hum.

I guess my main question would be - what other connections need to be tightly wound around each other and placed at 90 degree angles? Just the A/C leads from the output tranny and the speaker-out wires?

Also, what sort of material should be used to insulate the chassis from the choke/trannies?

[Don Moose]

Lower-level wires (grids) need to be at 90 degrees to higher-level wires (plates).

Other than the heater runs and speaker pair, twisted pairs won't help you much.
Shielded cable (RG-174 coaxial), especially on grid runs, can help kill hum, but it's not a panacea. You will probably have to fiddle with which end of the shield to ground - usually only one end gets grounded.