When to prune raspberries

So, every year you have to cut back the old vines to the ground and it is good to drape the new vines over a support of some sort, tying where appropriate. Usually this is done during the winter. My question is, does it hurt the health of the vine (root) to cut back the old vines as soon as they have stopped bearing fruit? or should I wait until winter? I would like to get it done sooner rather than later.

What do you think?

I cut mine back shortly after the fruit was all gone from them. Hope it doesn't hurt them but it seems to have made the rest of the vines happy for the extra light and airflow

It mostly depends of what type you are growing. I grow the primocanes...
 So they produce on new first year canes, produce the second year on side branches, then the whole stalk turns brown and dies back. That's when I cut them, just before bud break.
This way I know I am cutting old spent canes.  I have found this method produces the heaviest crops.