[sdiy] Ferrite Beads

[Ian Fritz]

At 02:14 PM 2/3/2011, David G. Dixon wrote:

>My panels are grounded at a single point (typically to one of the jack
>rings) taken from the PCB.  Modules are all connected separately to the
>power supply ground in a "star ground" configuration, but this is defeated
>as soon as anything is plugged into anything else, because then the two
>panels are connected through the cable shielding, so I must have ground
>loops all over the place.  Doesn't matter!  I also mount all of my boards on
>grounded metallic stooge brackets which cover the entire copper side of the
>board, so this might provide some extra noise insulation.  Otherwise, it's
>just dumb luck.

Ground loops don't hurt you if all the ground resistances are zero.  :-)

IOW, if you have star-type power distribution with nice heavy gauge wires 
then cross talk should be minimal.

Beads will help with high-speed (digital) hash, if that is a problem.  My 
TZ VCO has a bunch of beads and subregulated supplies to try to prevent 
syncing to the FM input signal.  It wasn't easy but I eventually got rid of 
the on-board x-talk difficulties.

Ian