Does this look like enough heatsink?

[CarlosT]

I'd add some heatsink grease between all layers for extra measure.

I think that the chunk of aluminum lineup uses is not insignificant and now your revised heatsink sounds much better, too.

My point about copper tubing was twofold...extra surface area for a given weight of metal and copper as a superior heat conductor.

Also...painting aluminum in heavy black enamel can help it to radiate heat...I think the heatsink gurus call this emmissivity

 

[tamasic1]

computer heat sink

Go to a computer repair place. They will have plenty from old computers and probably give you what's lying around.

 

[lineup]

We can think and guess
and it will only be guessing.

When I say that LM3875 at normal listening levels
'does not require very much heatsinking'
.. it is based on my experiences and knowledge.

Now the young ones wants to stress and get to the limit of
as much MAAXXXXIMALLLL POWEEEERRR!!!! as possible.
These, not always the young!, should have enormous heatsinks in whatever amplifier they use.
Even in preamplifiers .....
I guess they will calm down, when they get older and sensible
in their audio listenings.
When they can start enjoy nice music instead
------------------------------------------------

Furthermore
it is not at all difficult to determine like what heatsink you need.
Not if you use the excellent documentation and applications information
in the LM3875 PDf datasheet.

Let's stop guessing now
http://www.national.com/ds.cgi/LM/LM3875.pdf

See for example, the great heatsink
info in my attached figures and tables.
They are captured from LM3875 PDF Datasheet


Regards everybody
lineup