Sheet metal cooling

[Skorpio]

I am planning a F4 or F5 amplifier and I have all parts except the heatsinks.

I was wondering if it is possible to use a large (two, mono blocks) sheet of aluminum as heatsink?

The idea is to mount the amlifiers on an MDF buttom on the wall behind the speakers and letting the front plade be at 500x700mm aluplate?

I can see some potential problems:

How thick must the plate be to transform the heat away?
How do I calculate size/effiecency?
Do I need a think adaptor plate where output devices are montted?

[jacco vermeulen]

Originally posted by Skorpio
How thick must the plate be to transform the heat away?

http://en.wikipedia.org/wiki/Thermal_conductivity

Place an output transistor in the center of the plate, divide the plate in 4 sectors going from the transistor edges to the corners of the plate.
Then set up a differential equation for the cross section plate area A from the transistor edge to the edge of the plate.
Think the transistor edge at say 50C and the plate edges at ambient.
Aluminium conductivity is 237W/M*K, you also know the dissipation number.
Solve the differential equation for x going from 0 to either 0.25m or 0.35m and add up the 4 quadrants.