It works fine in the amp from my pics: the heatsink base is 0.300" , copper thickness 0.125", temp approx 50*, over period of 5 years of everyday use, no problems observed.
Hi Peter
You are quite right about copper not release heath well.
I got a few off cuts of 13mm (1/2) aluminium bar left from the case and I will try them
Still I think that dissipation will be beter than the plasitic body exposed to air.
I noticed you use the large vasher to distribute the mech pressure to a larger area of the mosfet.
With the clamp I can get more pressure and is more evenly distributed so no mosfet lifting off if to much torque is aplied and I wont strip the treads while swapping mosfets around.
By the way copper plate is 10mm thick base plate of the heath sink 12 mm so 0.39 and 0.47 respectively.
Originaly I was planing to use the 5mm (bar on the clamp) as heath spreader but when I went to get it they had the ones fitted to the heat sink as scrap.
I just could not resist to get it.
Tanks for the comments all valid points I must say and those pictures are just briliant.
what is it? tell as more please.
You are quite right about copper not release heath well.
I got a few off cuts of 13mm (1/2) aluminium bar left from the case and I will try them
Still I think that dissipation will be beter than the plasitic body exposed to air.
I noticed you use the large vasher to distribute the mech pressure to a larger area of the mosfet.
With the clamp I can get more pressure and is more evenly distributed so no mosfet lifting off if to much torque is aplied and I wont strip the treads while swapping mosfets around.
By the way copper plate is 10mm thick base plate of the heath sink 12 mm so 0.39 and 0.47 respectively.
Originaly I was planing to use the 5mm (bar on the clamp) as heath spreader but when I went to get it they had the ones fitted to the heat sink as scrap.
I just could not resist to get it.
Tanks for the comments all valid points I must say and those pictures are just briliant.
what is it? tell as more please.
Not true. Copper should release heat better than aluminum. It just soaks heat quicker and it seems hotter.
That is actually not true, when talking about chunk of metals.
I don't know how many of you did cut copper, but whenever I do it, I'm noticing how quickly it heats up and how long it takes to cool down.
Out of curiosity, I did a little experiment today. I heated up two bars, copper and aluminum, approx 10mm thick and placed them on a wooden surface, observing temperature change with infrared thermometer and later manually with my hand.
Out of boiling water, surface temperature was approx 60deg. I waited for it to stabilize down to 50deg and turned on the timer.
It was going down equally slow and after 5min it was 35deg, after 7min 32 deg and finally, after 10min approx 30 deg on surface of both bars.
However, when I touched it with my hand, I couldn't hold it comfortably on a copper bar, it still felt very hot after few seconds. With aluminum, I could do it much longer, which leaves us with an interesting conclusion: which material is actually better for using as clamps?
Personally, I stay away from clamps, I tried them briefly in Gainclone and didn't like the sonic effect pressed on material was introducing, since then I always use screws with washers.
If somebody mentioned expansion before, just imagine what happens to a device "vised" between jaws of copper 😉
One last remark, the plastic that output device is encapsulated with, certainly does not possess the best thermal characteristics. So if your bar gets really hot, the device itself acts as an insulator between the bar and the heatsink: instead of improving thermal dissipation from a device, you may be actually adding more heat.
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It's my Zv9 aka F3: http://www.diyaudio.com/forums/pass-labs/85590-another-zv9-completed.html#post993637
Looking back at it, I must say it's the best chassis design I did so far. I prefer to stay away from "boxes" these days 😉
Peter D..... I've admired your chassis design for quite a while.... Very creative, and very well accomplished....!
For my interest--what do you have for "high end" machining? Do you have a large bandsaw, vertical mill, etc? Just curious.....
Ken
For my interest--what do you have for "high end" machining? Do you have a large bandsaw, vertical mill, etc? Just curious.....
Ken
The copper feels hotter because it is transferring more heat to your fingers.
The aluminium feels cooler because it cannot conduct heat as well.
But there is a part you have overlooked.
The Specific Heat of the two metals is different.
Even though they are both heated to the same starting temperature, they do not contain the same energy.
The volumetric heat capacity are 3.45:2.42 for copper:aluminium.
The copper started off with ~42% more energy. If they did cool down at the same rate in air, then that confirms that the heat flow out of the copper was ~ 42% more than the aluminium.
Copper will always make a better heatsink than aluminium when you compare on a dimensional basis (volume and/or area)
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So maybe it feels hotter because it also contains more energy due to Specific Heat?
Please don't mix up subjects, we are specifically talking about slabs of metal, which cannot be regarded as heatsinks
"If there is no air or fluid flow around the heat sink, the energy dissipated to the air can not be transferred to the ambient air. Therefore, the heat sink functions poorly." (Wikipedia)
Please don't mix up subjects, we are specifically talking about slabs of metal, which cannot be regarded as heatsinks
"If there is no air or fluid flow around the heat sink, the energy dissipated to the air can not be transferred to the ambient air. Therefore, the heat sink functions poorly." (Wikipedia)
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Here is the real question - is aluminum the 'wrong' material?
It can't be, as it is used successfully in many designs. Yes, it is used for more reasons than just it's heat transfer... It's easy to extrude into complex shapes (fins) and it's cheap (compared to copper, especially) and so on.
The end goal is to get the hot part of the transistor cool, right? If there is a marked increase in the heat-wicking ability of a heatsink assembly if a piece of copper is added in-between the FET and the aluminum fins, then that's awesome! Sign me up!
But for all this gnashing of teeth, wouldn't it be much easier to use a bigger heatsink?
And what about a very small, very quiet, slow fan? Nelson himself says that moving just a little bit of air makes a marked and noticeable difference...
It can't be, as it is used successfully in many designs. Yes, it is used for more reasons than just it's heat transfer... It's easy to extrude into complex shapes (fins) and it's cheap (compared to copper, especially) and so on.
The end goal is to get the hot part of the transistor cool, right? If there is a marked increase in the heat-wicking ability of a heatsink assembly if a piece of copper is added in-between the FET and the aluminum fins, then that's awesome! Sign me up!
But for all this gnashing of teeth, wouldn't it be much easier to use a bigger heatsink?
And what about a very small, very quiet, slow fan? Nelson himself says that moving just a little bit of air makes a marked and noticeable difference...
> If there is a marked increase in the heat-wicking ability of a heatsink assembly if a piece of copper is added in-between the FET and the aluminum fins, then that's awesome! Sign me up!
Unfortunately it does not, else everyone would be doing it. The bottle neck is the thin layer of thermal compound between the device and the copper, and copper to the sink, even if it is say 0.1mm thin. It can all be calculated. No magic, just science.
> And what about a very small, very quiet, slow fan?
That works wonders. I once had a heatsink for a proto which was under-dimensioned. It went to 60+°C. A slow running fan gets it down to 40°, at an ambient temperature of 25°C.
Disclaimer : this only applies to that particular case. I am by no means suggesting that you always get a factor of 2 with a fan.
Patrick
Unfortunately it does not, else everyone would be doing it. The bottle neck is the thin layer of thermal compound between the device and the copper, and copper to the sink, even if it is say 0.1mm thin. It can all be calculated. No magic, just science.
> And what about a very small, very quiet, slow fan?
That works wonders. I once had a heatsink for a proto which was under-dimensioned. It went to 60+°C. A slow running fan gets it down to 40°, at an ambient temperature of 25°C.
Disclaimer : this only applies to that particular case. I am by no means suggesting that you always get a factor of 2 with a fan.
Patrick
I don't use any special machinery, this is all I need to work with aluminum. I recently added sandblaster to my workshop.
Peter,
think about it from the other direction.
Take a loaf of bread, a lump of stone and a block of aluminium outside and leave them to cool overnight.
Go out in the morning and feel each object.
The aluminium will feel coldest and the loaf of bread will feel warmest. That has virtually nothing to do with specific heat. That is how well the object is transferring heat from your warm fingers into the body of the mass/object.
If the temperatures are sub zero, you may find that you stick to the aluminium, due to the moisture on your fingers freezing !
A block of copper or of aluminium or of cast iron can operate as a heatsink. The relative performance will depend on the how well the heat can flow into the sink and how well the heat can flow out of the sink.
I see absolutely no value in your quote from Wiki. It is out of context and as a result is totally confusing to any that are not sure about the subject you have apparently found corroboration for.
think about it from the other direction.
Take a loaf of bread, a lump of stone and a block of aluminium outside and leave them to cool overnight.
Go out in the morning and feel each object.
The aluminium will feel coldest and the loaf of bread will feel warmest. That has virtually nothing to do with specific heat. That is how well the object is transferring heat from your warm fingers into the body of the mass/object.
If the temperatures are sub zero, you may find that you stick to the aluminium, due to the moisture on your fingers freezing !
A block of copper or of aluminium or of cast iron can operate as a heatsink. The relative performance will depend on the how well the heat can flow into the sink and how well the heat can flow out of the sink.
I see absolutely no value in your quote from Wiki. It is out of context and as a result is totally confusing to any that are not sure about the subject you have apparently found corroboration for.
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And that is exactly my original point... Nobody messes with copper, they just use a bigger heatsink.
It really makes me want to find some aluminum extrusion similar to the Aleph amps - I really like the hedgehog look and admire the elegance of having an amp that's all heat transfer area... 🙂
First of all to all our Japanese friends
I hope you are all well...
Same more progress today.
Filed the clamps still load of sanding and polishing to do.
1) Earth block for the star connections them screws are not going to move
The same arrangement on the back of the heat spreaders
2 3) Side panels should keep the air flowing.
The "rustic" look is growing in to me still I will have plenty of time to do a proper job while I listen to it.
Aint a Steinway but as long as it sound like one I be happy
Tanks Peter for the Z9 pictures is really mind blowing
4) Transformer inside its own enclosure.
It will be mounted on the back right at the top so maybe I will not use it but thought same comments may help.
I think is well worth looking in to this especially if you have a "traditional" box
With the traffo in the middle.
I hope you are all well...
Same more progress today.
Filed the clamps still load of sanding and polishing to do.
1) Earth block for the star connections them screws are not going to move
The same arrangement on the back of the heat spreaders
2 3) Side panels should keep the air flowing.
The "rustic" look is growing in to me still I will have plenty of time to do a proper job while I listen to it.
Aint a Steinway but as long as it sound like one I be happy
Tanks Peter for the Z9 pictures is really mind blowing
4) Transformer inside its own enclosure.
It will be mounted on the back right at the top so maybe I will not use it but thought same comments may help.
I think is well worth looking in to this especially if you have a "traditional" box
With the traffo in the middle.
Once again, you are mixing things. We are taking here about bars of metal inside the the amp, with no air circulation present (at least that's my assumption). So the piece of metal will not dissipate heat, because there is no air flow, no matter if it's aluminum, copper or diamond. Hence my quote:
"If there is no air or fluid flow around the heat sink, the energy dissipated to the air can not be transferred to the ambient air. Therefore, the heat sink functions poorly." (Wikipedia)
WELL WELL WELL
We got in the house some one that at one point suggested to solder the mosfets to the cooper directley should I fetch that post...
Any way one thing I would like to make clear the main reason why I am using the heat spreaders is so I will not strip the treads on the heat sink, this is just a Mule so I will keep triing different things, different Mosfet different number of mosfets balanced and what not may even turn the thing in to the A75.
Copper conduct heat beter than aluminium Silver Diamond and Graphene are beter still.
Is going to take a while to get the Diamond so I am using copper it was Cheap at the time.
We got in the house some one that at one point suggested to solder the mosfets to the cooper directley should I fetch that post...
Any way one thing I would like to make clear the main reason why I am using the heat spreaders is so I will not strip the treads on the heat sink, this is just a Mule so I will keep triing different things, different Mosfet different number of mosfets balanced and what not may even turn the thing in to the A75.
Copper conduct heat beter than aluminium Silver Diamond and Graphene are beter still.
Is going to take a while to get the Diamond so I am using copper it was Cheap at the time.