Dual Class-A Line and Headphone Output Board Documents

[Gold]

Plan B. Hopefully this will take care of it. I did a press fit of the copper rod in to the aluminum. The rods provide good opportunities for improvised mounting. Both rods were the same length. I couldn't get the shorter one into the vise to bend it so I tried removing some material from the rod to bend it easier. I went slow but by the time I removed enough material it was too weak and broke. Oh well. Live and learn.

[Gold]

Works great. There is a temperature differential between the aluminum and the the copper but it's not large. I can leave my finger on the aluminum at least two seconds longer than the way it was before. I can leave my finger on the copper three or four seconds longer than the aluminum.

[JR.]

Nice, copper is very low thermal resistance. A little more surface area on the outside might be nice, but probably not necessary.

JR

[Gold]

It would have been better if the second rod didn't break... It could be better but this is good enough. I left it on all day and it maintained a decent temperature.

[JR.]

You might be able to solder/braze the broken piece back on...

JR

[Gold]

I have this... I think this box is done enough as it is now.

[ricardo]

I've done experiments with heatpipes to get heat from speaker units to a heatsink on the external back of the cabinet. This was to reduce thermal compression from Cu coils heating up. Only worthwhile on the midrange unit of a big 3 way speaker. It would be very useful in a small 2 way but the cost would then be crazy.

The pipe went up the pole and stuck into the external heatsink. The bottleneck was pipe to heatsink. There was hardly any difference between the pole (inside the coil) and the end of the heatpipe.

Maybe a bit overkill but you might be able to get a sample heat pipe if they thought you would buy 100s

An important point to note is that the success of "chip to ambient" is actually measured by how hot the external heatsink gets with a given power dissipation. Caveats about comparisons with similar heatsink size bla bla .. it means the heatsink is closer to the chip temperature. It's the temp difference between heatsink & ambient that drives how much heat it is taking from the chip (and into the air).

If the heatsink is cool, not much heat is coming that way and the chip will be hotter to drive heat through less efficient paths.

You can play games like handing someone a heatpipe to stir his hot tea or coffee

[JR.]

Copper round stock is not a heat pipe..

He seems to be happy with what he has done...

You don't go class A if heat bothers you.

JR

[Gold]

I've done experiments with heatpipes

I had never heard of a heat pipe. A quick search turns up a tube filled with liquid. I think a home brew heat pipe is asking for trouble. I see leaks. This is only going to sit on my bench and be dragged around for troubleshooting if needed. Close enough for me.

[ricardo]

I had never heard of a heat pipe. A quick search turns up a tube filled with liquid. I think a home brew heat pipe is asking for trouble.

If you ever get a chance, don't hesitate to have a play with one.

The heat transfer is at 'sorta the speed of sound' in a heat pipe. The bottleneck is always how to get the heat into one end and out the other.

But I did say it was overkill. If you check $$$, you'll see why we didn't use it in production but a fat slug of Aluminium instead.