Thanks very much Lugia for your generous advice, it's much appreciated!
I will look into the ferrite clips. Are there particular ones I should be getting?
When you say wind the card between the "brick" and the cab, what do you mean by that?
I'm unsure where to attach the clips.
I am using a 15V 3.34A power brick (as supplied) for the EP-96 case, which should be plenty of Amps to power both the SV-1 and Voltage Research Laboratory modules?
Thanks also Ronin1973, I will try to eliminate each module one by one.
My modular racks are plugged into separate power points from my mixing desk, so I don't think that should be the problem?