Water Cooling

[Variac]

Its certainly cheaper to make t he Grey version with a length of copper pipe soldered to a plate of copper as I already mentioned. I guess you have to see how much a 12" length of 1/2" pipe and a plate of copper the correct size cost. If you are doing more than one, then the cost savings would be significant.

[jacco vermeulen]

i just found this cooler, the lines are for different cooler length.
No copper pipes, only threaded holes for screw-in plugs.
For agressive fluids this one is made with pressed-in copper piping too.

Converting to US means a 16" x 3" x 0.6 " alloy plate with two 0.4" diameter holes has a thermal factor of 0.005 if the cooling fluid does a little over 2.5 gallons of water per minute.
Above that waterspeed the heat doesnt go through the alloy fast enough.

Supposing 30 degrees over ambient this little baby is able to cool 6000 Watts.

[BrianDonegan]

This is actually very close to what I have been thinking about the past few days. I was looking at Peter Daniel's Patek Amp, and thinking that a similar solution (central copper bar heatsink) could be used for a liquid-cooled class A design. I wouldn't copy his design, just the copper bar backbone. That is one beautiful little amp.

So, I'm thinking a 3x6cm copper bar with 2 - 1cm (or so) holes bored through it length wise. Then press a semicircular copper return into the front, and two small threaded fitting on the back. Hook it up to an external cooler/pump and off you go.