An amplifier without any heating

[badboy6120]

hello everyone

I always was wondering If I could build an amplifier without any heating and heat sink
can anyone help me with it?????
I want an amplifier that doesn't need any heat sink and works with room temperature and doesn't heat up at all in maximum power

I have a very good amplifier but unfortunately it doesn't have this thing I'm looking for(It heats up)
the power that I'm looking for is around 250W or higher

thank U

 

[luka]

without any heat sink... no
without any heat produced... no

since there is no amp on the world, that is 100% efficient, the is heat generated

Now, that doesn't mean, you can't get amp without heatsink. If we are talking small powers, below say 2w, even better if below 1w, like headphone amp, then yes you can have amp without heatsink, since IC or components themself (pcb is to some point heatsink too) can dissapate some heat. They can get hot, but not that much that it would hurt them.

If you are taking about power levels in hifi amps or in several kw range, then there is no amp that won't have heatsink

 

[Tekko]

Such amplifier doesent exist!!

All amplifier class d included will get warm/hot, forced air cooling with fans is the only way to keep an amp from reaching much above ambient, this still requires a quite beefy heatsink though.

But even if you keep the heatsink cool, the transistors may still be at 50-100deg C inside due to thermal resistance.

 

[Saturnus]

Is it possible to build an amp that doesn't produce heat? Yes, all amps don't produce heat until you plug them in.

Heat is the by-product of work. So a working amp will always produce heat, always. The efficiency tells you how much heat is produced for an amount of work. And since perpetual motion machines aren't exactly common place these days efficiency will always be lower than 100%, so it's physically impossible to build a working amp that doesn't produce heat.

 

[goosewing]

If you are taking about power levels in hifi amps or in several kw range, then there is no amp that won't have heatsink

Except for valve amps which don't require heatsinks at all, they sure produce the heat though.

 

[luka]

Except for valve amps which don't require heatsinks at all, they sure produce the heat though.

True! and this would be probably the only kinda amp (that I know of) that would do this, BUT

doesn't heat up at all in maximum power

As this being the requirement, valve amps are out

 

[poynton]

If the amplifiers metal case does not count as a heatsink and there are sufficient power devices with TO3 case mounted on it and the output power is not excessive for normal sound levels ....

Maybe possible.?


.

 

[luka]

metal case seems very logical way of thinking it

 

[poynton]

There are many good looking metal cases where the heatsink is not obvious.
They can also be fitted "internally" so as not to be obvious .

Basically, use a large metal mass as a heatsink.

Is the reason for "no heatsink", to minimise the heat produced or cosmetic reasons?



.

 

[AP2]

Hi,
Just for curiosity. the argument is interesting, considering that this is a special case.
yes, there to SDA-300 up to 300w (4R) without heatsink, just a profile (60x27mm) to mount the mosfets. you can see on audiopower -> shop.
loses only the final stage 700mV from supply rails, the clips very clean.
Just to see him, it is out of production, then it is offered with a big discount.
obvious that the assistance will be provided.

Regards
Roberto P.

 

[coolhead]

You try small tripath amp like TA2024 that is 2x8watt. It produce heat but it doesn't need a heat sink and sound very decent. I have one in a small seal box and is turn on most of the time.

 

[goosewing]

metal case seems very logical way of thinking it

Preferably a big thick aluminium one ...

with fins on it

 

[badboy6120]

thank you all for your attention

very well
I guess there is no amp without heating in high power ( around 250W )

anyone doesn't mention that how about I build an amplifier with a power more than I need and I just use half of this power
for instance : I build a 600W amp but I only use 250W of it ???????

 

[luka]

for instance : I build a 600W amp but I only use 250W of it ???????

Right, but that would be more class A amp...

in class D, you are looking some where between 85 and 95% of usable (output power). so only 5-15% goes into heat

 

[DF96]

I guess there is no amp without heating in high power ( around 250W )

As others have said, there is no such thing as an amp of any power which does not produce heat, except when it is switched off. You seem to find this hard to accept? Do some reading on thermodynamics.

What is your actual application? Some heat is unavoidable, so how much is acceptable?

 

[Andrew Eckhardt]

One thing you could try is multiway active with a sub/woofer amp using a very low switching frequency (30kHz?) Should be good enough for ~100Hz bandwith, although the output filter components will be bigger and more expensive. National Semiconductor had an IC like this, with a 75kHz switching frequency, but it wasn't extraordinarily efficient (according to the datasheet) and it went obsolete.

 

[AP2]

Hi,
I do not agree. if the efficiency is very high, it is possible. I have an Unregulated SMPS for amplifier in class AB Mosfet 400w (4R). The SMPS MOSFET's do not even have a small profile. it is obvious that in this case the dissipation is very small. it is clear that to get there is also a special transformer.
So, although you can have on the class D, 4w dissipation max of 300w. .. but nothing is simple or already done.
Also, I not understand this special application without an small heatsink??

Regards

 

[ingenieus]

The old Naim amps did not have conventional heatsinks. The cases were made of extruded aluminum, about 4mm or so in thickness. That got rid of the heat quite well.

On the subject of heat dissipation, has the idea of liquid cooling for audio amps been tried? Something along the line of those fancy CPU coolers for overclocked PCs.

 

[goosewing]

The old Naim amps did not have conventional heatsinks. The cases were made of extruded aluminum, about 4mm or so in thickness. That got rid of the heat quite well.

On the subject of heat dissipation, has the idea of liquid cooling for audio amps been tried? Something along the line of those fancy CPU coolers for overclocked PCs.

For sure liquid cooling has been used. Way back when I was a student and a pal was into discos he built an amp that produced way more heat than we could afford on student budgets, so it had tiny heatsinks whose fins were drilled to accept copper pipe connected by some hosepipe to the room's sink and tap

 

[!]

Hi,
I do not agree. if the efficiency is very high, it is possible. I have an Unregulated SMPS for amplifier in class AB Mosfet 400w (4R). The SMPS MOSFET's do not even have a small profile. it is obvious that in this case the dissipation is very small. it is clear that to get there is also a special transformer.
So, although you can have on the class D, 4w dissipation max of 300w. .. but nothing is simple or already done.
Also, I not understand this special application without an small heatsink??

Regards

This is not (practically) possible. Per your example of 300W output, let's be generous and say that is across two channels instead of one, so 2 x 8 ohm (speakers) load = 16 ohm. That means 18.75V rail to rail output through a couple of mosfets each channel, 4 total so let's add 0.8V for those (an impossibly low 0.2V each just to show how impossible the whole idea is), . 300W / (18.75V + 0.8V) = 15A current, and this ignores all the losses in the amp anywhere else including the PSU.

15A * 0.8V = 12W loss (heat) in the last pairs of output transistors alone.