CPU coolers for chipamps?

[mobyd]

Given that the biggest problem with some of the more powerful chipamps (LM4780, TDA7293 etc) is getting a lot of heat away from a smallish object in a hurry, has anyone tried any of the commonly available CPU coolers typically used on Pentium class processors. Some of these boast impressive specs (0.3degC/W)
but I wonder what their bulk heat moving capacity is really like.
M

 

[pinkmouse]

Did you search before you posted? I think not!

There is lots of discussion on the use of CPU coolers for chip amps here.

 

[Bazukaz]

Cpu cooler is good , especially with a fan used. a fan can be set to low rotation speed to decrease noise.

 

[Vikash]

Given that the biggest problem with some of the more powerful chipamps (LM4780, TDA7293 etc) is getting a lot of heat away from a smallish object in a hurry

Is it? I wouldn't say heatsink requirements are exceptional by any means. Many people use just large blocks of aluminium/copper or the case itself if it's of reasonable thickness.

As pinkmouse has said, you should find plenty of discussions on CPU coolers. IMO, certainly no need to add a fan into the mix.

 

[Bazukaz]

A fan dramatically increses power dissipation of the heatsink.For myself , i don't like fans for noise , but a thermo-relay could be used , so fan turns on only on high output levels.

 

[jackinnj]

you can use an LM3524 (SG3524) as a temperature related PWM fan speed controller -- National has an application note on their website --

 

[sagarverma]

i use a diminishingly small heatsink on my tda7294 amp(that small heatsink is called flower),the heat sink has small 12v dc brushless fan,the whole cooling setup only four or five times the size of ic..the setup keeps the ic cool....its small but very unsafe bec if the fan fails the chip will burn out in few sec bec the heat sink is too small to sustain the heat transfer even for few mins.

moreover the heatsinking req. of the chipamps is not that much critical to be met by using fans and it can be easily achieved by using big heatsinks.

 

[Bazukaz]

Most of modern ICs have thermal protection , don't know about TDAs , but LMs really do.

 

[Leolabs]

The old TDAs do not have a good one,although in their datasheets,their stated that they have.

 

[zenon]

DC fans can easily run at lower voltages then they are rated, for my PC I have two 12v fans wired in series so they run slower (6v across each) and the noise dropped from quite loud to inaudible. The noise all comes from the speed.. slow those fans down and they will be silent.

 

[merlinx76]

My sub amp has 2 fans (which i slowed down) my source is my computer which has 2 fans, the computer on the bench behind me is even louder than mine, the fan for the dehumidifier in the next room is probably louder still. I despise fans... i want to be rid of them all... dont use fans

 

[Vikash]

i want to be rid of them all... dont use fans

Why people want to use fans is beyond me. To each his own I guess. Just use a bigger heatsink and take the fan out of the equation unless size is that much of a constraint. What am I missing? Sounds to me like it's a case of doing it for the sake of doing it. I'll say no more on the matter

 

[Bazukaz]

Fans are the option if you want to push the IC to its limits.With passive cooling it is hard to archieve less than 70 Degs Celsius(and sometimes even this) , if the amp is multi - channel and powerful.For myself , i don't like fans too.But they can be an option for high power applications.

 

[Nordic]

Alternatively drop the voltage to the chip until it has suitable power levels for use with whatever heatsink you have....

 

[EWorkshop1708]

But the hard part remains.................how to mount the chip to the CPU cooler.........

 

[dnsey]

But the hard part remains.................how to mount the chip to the CPU cooler.........

Not too difficult - use the double-sided adhesive pads or epoxy adhesives made for the job

 

[karma]

or use a metal drill bit and drill and tap a hole to screw it down

makes it really tight

 

[Bazukaz]

But the hard part remains.................how to mount the chip to the CPU cooler.........

Drill a hole into the cooler and fix with a screw.Use mica insulator with thermal paste.
Silicone pads have poor thermal transfer.

 

[triden]

sidenote:
What I did was make a temperature sensor applied to the heatsink that is combined with an opamp and comparator to turn a fan on when a certain temperature is reached. This way the fans only run when the half to. The circuit is fairly easy, but I havnt tuned it to operate best yet.

 

[Nordic]

The aluminium part is very easy to drill with any metal drillbit.....
Also, try to get rubber grommets to attatch the fan to the cooler they kinda look like 2 chesspawns stacked bottom to bottom...
Even quiet fans transmits lots of vibration, which is of course easier to detect in a PC as the whole case resonates with it...

I thought my specialy imported, custom made Yate Loon fans were quiet, until I put them on grommets.