N_Cook wrote:

For fan blown o/p devices the heatsink surely does not have to be much more
that a metal matrix for holding the devices to.

The larger area the better.


Does not have to be multifluted

That certainly helps.


or with those chisseled multi-vanes etc (sorry don't know the
generic term , end up curved )

Those increase surface area which is a GOOD THING.


or a great mass of metal for convection cooling

It most certainly DOES NOT need to have great weight. But almost none of the
colling in SR amp is classic convection anyway. What typically helps is maximum
surface area of the fins/vanes to create the best opportunity to let the heat
transfer to the air flow, but you can improve even that by 'slotting' the
'vanes' to create a slightly turbulent air flow.

Trust me I could write a lecture on the subject.

Graham