Found this very useful article by Kevin M. Tompsett on damping of a PSU output filter:
In Fig 4 there are 3 techniques shown to damp oscillation in the output C-L-C pi filter:
1. Resistor across the inductor
2. RC load on input
3. RC load on output
I can understand how techniques no. 1 & 3 work as they are loading the output of the filter to damp the oscillation, but I do not understand how no. 2 works. How can a RC load on the input of the filter stop oscillations on the output? It seems to me that the output LC can still resonate.
Any clarification of how technique no. 2 works would be well appreciated!