*my* Tubelab SE build...

[PaulyT]

Yeah, I was just kidding about the fan. I got a heatsink on the large side so that hopefully I won't need a fan, especially since my enclosure is going to be relatively open; just that the one I initially ordered was ridiculously large, as was the old cpu heatsink I had lying around. I was afraid it'd put too much mechanical strain on the small soldered-on heatsink and the ICs and PCB.

[oldmanStrat]

Originally posted by PaulyT
Yeah, I was just kidding about the fan. I got a heatsink on the large side so that hopefully I won't need a fan, especially since my enclosure is going to be relatively open; just that the one I initially ordered was ridiculously large, as was the old cpu heatsink I had lying around. I was afraid it'd put too much mechanical strain on the small soldered-on heatsink and the ICs and PCB.

I was initially going to use a Pentium heat sink, but mine wasn't going to be supported by the devices themselves. It sat on the bottom of the chassis, and contacted the existing heat sink via spacers. The problems I had with that arrangement was that I still needed to cut a channel in the heat sink for the PCB (it was still too far away from the heat sink) and I had no way to mount it - drilling a hole in a finned heat sink was just going to break a few bits, and it would still need to be a two step drill, one for the screw body (from the bottom) and one to capture the head of the screw (drilled from the top). Otherwise I'd need a very long screw and washer to make it all the way out to the top of the fins. The best way to do this is to use a thermal tape or epoxy - but it's generally expensive from what I could find.

I settled on the second heat sink to bolt onto the first even though it was smaller because I really do need to move some air through the box. With the top on the whole chassis gets very warm! Russ's solution of using a finned chassis and conducting the heat to the sides is exactly the way that I would do it - if I had the tools and the time/money to implement it.

I know that I've made things even worse by using my UOS (Used Old Stock) 5U4 rectifier. The Edcor power xfmr gets very toasty after a few hours and that is just going to put more heat into the top plate.

I'm sure your convection cooled box will be just fine. Although the look of that giant top mesh cage might be a little odd. And btw, I bought one too for this chassis, but I like the way it looks without it, and since the cage is steel - it doesn't come close to matching the aluminum. I doubt that I could paint it any color that would make it look good...

[PaulyT]

Yeah, I did manage to mount the old pentium one, just as you said - small holes in the bottom plate, larger holes through the fins on top. It was possible with a drill press, but it was tricky. It looks more than a bit ridiculous, though, maybe I'll post a pic in my thread if I get a chance before the new one comes, just for grins. You all will laugh.

[Evenharmonics]

Originally posted by PaulyT
Yeah, I was just kidding about the fan. I got a heatsink on the large side so that hopefully I won't need a fan,

My TSE chassis is relatively compact and by having an extra heat sink for U1, it didn't need a fan.
Why add more noise.

[oldmanStrat]

Originally posted by Evenharmonics


My TSE chassis is relatively compact and by having an extra heat sink for U1, it didn't need a fan.
Why add more noise.

Well I've designed a lot of electronics - workstations, routers, RAID cards etc... and they all needed fans & airflow. With some of the temps that I see on the silicon in this design it just seems normal to me to want to put a fan in. The challenge is to make it quiet!

I actually am considering a peltier module, but I've never used one before - but that would only help on the one heat sink and not the mosfets...

http://search.digikey.com/scripts/Dk...me=102-1665-ND

[Ty_Bower]

Originally posted by oldmanStrat
I actually am considering a peltier module, but I've never used one before...

A thermoelectric heat pump adds to your total heat load. Whatever power is required to run the peltier plus whatever heat it pumps off the cold side all gets transferred to the hot side. You'll need a bigger heatsink and noisier fan to manage the increased thermal load.

[rknize]

Try a small squirrel cage fan, like a PCI slot fan. At full speed they are very quiet...much quieter then any 40mm fan. At half speed they are nearly silent. Just be sure to get a ball bearing one. With a little extra lubrication I can get many years of service from a cheap ball bearing slot fan.

[boywonder]

Originally posted by Ty_Bower


A thermoelectric heat pump adds to your total heat load. Whatever power is required to run the peltier plus whatever heat it pumps off the cold side all gets transferred to the hot side. You'll need a bigger heatsink and noisier fan to manage the increased thermal load.

So I can't air-condition my house by leaving the refrigerator door open?

I also have a CPU Peltier staring up at me saying "use me".......

[oldmanStrat]

Originally posted by Ty_Bower


A thermoelectric heat pump adds to your total heat load. Whatever power is required to run the peltier plus whatever heat it pumps off the cold side all gets transferred to the hot side. You'll need a bigger heatsink and noisier fan to manage the increased thermal load.

Or just conduct the heat to the case...

[tomchr]

Originally posted by oldmanStrat


Or just conduct the heat to the case...

Yeah, if the power dissipation is relatively small and you are using an aluminum chassis, that works well.

Those CPU heat sinks are pathetic without a fan. They are built for operation with airflow. And they do that quite well. However, to me, audio and fans don't mix. I'd rather design the circuit to dissipate less power -- or use a bigger heat sink. But hey.... Maybe that's just me.

~ Tom