Coulomb said:
No way you are going to reach as low as 57 deg. When you connect heatsinks they start acting as one. For example when you look at PedroO his construction; most side fins of his construction can not breath freely any more.
As well as when you have one heatsink this heat sink can use all cool are around itself. When you have two heatsinks near each other they have to share the are around themself -> higher tempratures!
I experience this with two heatsinks which I bonded side to side. It should have been enough (when you look at the specs) but the fact was when I run them close together (like in a case) the temperature was higher!
Edwin
PedroO,
Main problem here will probably be that the heat transfer will be inefficent as heat is transferred close to two of the sink and the third is connected through the 2 copper (?) bars. The heat possibly will not be transferred quick enough from the fixing point position (through the heat conveyors of 5 by 25 mm or similar) to the last sink and that sink will reach a lower temperature than the others and they will in turn reach higher temperature than calculated.
IMHO you need more distribution of the heat.
/UrSv
Main problem here will probably be that the heat transfer will be inefficent as heat is transferred close to two of the sink and the third is connected through the 2 copper (?) bars. The heat possibly will not be transferred quick enough from the fixing point position (through the heat conveyors of 5 by 25 mm or similar) to the last sink and that sink will reach a lower temperature than the others and they will in turn reach higher temperature than calculated.
IMHO you need more distribution of the heat.
/UrSv
I design the sinks (and PSU) to dissipate 150W/ch.
So the temperature elevation would be around 25ºC.
Maybe I can't equalize the heat distribution in all sinks, but to me only a real test and a termometer can say I'm rigth or wrong
lots of guys think the heatsinks are OK but when they fire it up
another thing:
if the sink becomes too hot ( I doubt it) I can allways put a fan under it. these sinks are designs for it. just see the slots is the edges: they are for putting a metal sheet to restrain the air flow.
Or maybe water cooling
those holes are asking for it
So the temperature elevation would be around 25ºC.
Maybe I can't equalize the heat distribution in all sinks, but to me only a real test and a termometer can say I'm rigth or wrong
lots of guys think the heatsinks are OK but when they fire it up
another thing:
if the sink becomes too hot ( I doubt it) I can allways put a fan under it. these sinks are designs for it. just see the slots is the edges: they are for putting a metal sheet to restrain the air flow.
Or maybe water cooling
those holes are asking for it
Anthony,
FYI, the 57 degree calculation was done by Herm.
As for the waving look of the heatsink, doesn't the new "Viola" amp has that look? Don't know how it actually looks in real life becasue I haven't seen one in the store yet.
PedroPO
Regarding Acad, you have mentioned somewhere before but as usual I can't find it. My question is how do you convert from Acad to be able to post it here. You said something about convert to bmp and then use photoshop to convert to jpg? Could you be more specific please? I want to try to see if I can convert it too ... just for the fun of it. Software I've got are Adobe Photoshop, IrfanView & Adobe Acrobat 5.0.
FYI, the 57 degree calculation was done by Herm.
As for the waving look of the heatsink, doesn't the new "Viola" amp has that look? Don't know how it actually looks in real life becasue I haven't seen one in the store yet.
PedroPO
Regarding Acad, you have mentioned somewhere before but as usual I can't find it. My question is how do you convert from Acad to be able to post it here. You said something about convert to bmp and then use photoshop to convert to jpg? Could you be more specific please? I want to try to see if I can convert it too ... just for the fun of it. Software I've got are Adobe Photoshop, IrfanView & Adobe Acrobat 5.0.
fcel
If you have autocad, just type at command line - bmpout - then a popup "create BMP file" will appear. just that. If you dont like command line then try File-Export-Bitmap
roddyama
Do do you want the dwg or bmmp is just fine for you?
fell free to ask. I don't know if I can ppost dwg in the forum but I'll email it to anyone who want's it.
Tall feet wil be a must, I'm sure. let's wait for a temp test. maybe this weekend
If you have autocad, just type at command line - bmpout - then a popup "create BMP file" will appear. just that. If you dont like command line then try File-Export-Bitmap
roddyama
Do do you want the dwg or bmmp is just fine for you?
fell free to ask. I don't know if I can ppost dwg in the forum but I'll email it to anyone who want's it.
Tall feet wil be a must, I'm sure. let's wait for a temp test. maybe this weekend
If anyone wants to see more pics of my aleph 5 and some temperature readings, please jump to
http://www.diyaudio.com/forums/showthread.php?s=&postid=70418#post70418
(I dont want to steal this thread
http://www.diyaudio.com/forums/showthread.php?s=&postid=70418#post70418
(I dont want to steal this thread
hey i'm building a 1.2 but i'm having problems finding big enough caps for my PS. i bought pcb's from kristijan and he suggests 8 x 68000uf at 75V. those are hard to find. i have two questions - first - does anybody know where to find any that big? and second is - would it be better to have more smaller caps to equal the same capacitance because of the slow response time of the bigger caps?? i thought i read nelson saying that if that was a concern, to use a combination of big and small?? which method would be better??? any help would be greatly appreciated!!!! thanks greg
Hi Pedro,
I have been watching your project proceed along, but I have one question. How does the heat from your output transistors transfer to your rear heatsinks? These are the ones with the toroids on them. I don't see any massive piece of copper or alumnium connecting all of them together in your case. My layout for building the Aleph 2's is similar but I am using different, much larger sinks. It would seem to me that you could get much better heat transfer if you somehow connected the large flat face area of all three sinks together. In my case there is going to be 2 transistors per heat sink and my wiring will be a bit long to the last sink, but not overly long.
Mark
I have been watching your project proceed along, but I have one question. How does the heat from your output transistors transfer to your rear heatsinks? These are the ones with the toroids on them. I don't see any massive piece of copper or alumnium connecting all of them together in your case. My layout for building the Aleph 2's is similar but I am using different, much larger sinks. It would seem to me that you could get much better heat transfer if you somehow connected the large flat face area of all three sinks together. In my case there is going to be 2 transistors per heat sink and my wiring will be a bit long to the last sink, but not overly long.
Mark
Mark A. Gulbrandsen
You are wrigth.
The heat doesn't transfer isn't very good to the (front) heatsink.
My initial idea was to put 2 fet's /sink, bud I decided to take a change. the sinks now are at 49º. The amp looks alot cooler this way
see this post
http://www.diyaudio.com/forums/show...70418#post70418
You are wrigth.
The heat doesn't transfer isn't very good to the (front) heatsink.
My initial idea was to put 2 fet's /sink, bud I decided to take a change. the sinks now are at 49º. The amp looks alot cooler this way
see this post
http://www.diyaudio.com/forums/show...70418#post70418
OK so here is a question, which would you prefer?
1) A seperate Power Supply driving two Aelph 1.2 Mono Blocks? Stereo = 3 units.
2) Each Mono Block has it's Power Supply integrated in the same Chassis? Stereo = 2 units.
3) Each Mono Block has a seperate Power Supply of it's own in a second Chassis? Stereo = 4 units.
Your thoughts anyone?
Anthony
1) A seperate Power Supply driving two Aelph 1.2 Mono Blocks? Stereo = 3 units.
2) Each Mono Block has it's Power Supply integrated in the same Chassis? Stereo = 2 units.
3) Each Mono Block has a seperate Power Supply of it's own in a second Chassis? Stereo = 4 units.
Your thoughts anyone?
Anthony
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