Why so much resistance to heat sinks? Can't you walk outside and find a dead soda-pop can?
(Shortbus beat me to that one! )
Any old piece of metal will work (better than nothing) if it's flat.

I've done the penny trick once or twice.

 

"Linear" means, "linear". It does not mean, "Needs a heat sink" or, "Doesn't need a heat sink".

 

Why so much resistance to thermal paste? You live in the U.S. You can buy thermal paste.

 

"Linear" means, "linear". It does not mean, "Needs a heat sink" or, "Doesn't need a heat sink".

OK, I see. Some linear systems need heat sinks, including an LM386, but not all.

Why so much resistance to thermal paste? You live in the U.S. You can buy thermal paste.

Yes. I can buy a Ferrari, too (a used one).

 

Good news. Thermal paste is cheaper.

 

Do you mean that using a wad of cooking foil without thermal compound wouldn't be very effective? I assume by thermal compound you mean silicon gel or thermal grease.

Not to be confused with silicone grease, I use Wakefield thermal compound.
Max.

 

I'm confused. Isn't this also a linear system:

It does not require a heat sink, although it did when the value of R3 was 1kΩ and there was no capacitor wired in series with the speaker.

Being linear does not mean that you need a heat sink -- which is why I said IF you needed a heatsink for the TIP31.

In the circuit above, the current that is being turned into power in the speaker is flowing in R3. In the circuit with the TIP31 it is coming through the TIP31 and (I'm assuming) it would be coming through the LM386.

 

I have built several amplifiers with the LM386, never used a heat sink, and never burned out an LM386. Neither I have I ever seen a heat sink used on an LM386, so I don't think it's needed.

 

I have built several amplifiers with the LM386, never used a heat sink, and never burned out an LM386. Neither I have I ever seen a heat sink used on an LM386, so I don't think it's needed.

Thank you. I was just about to ask why none of the Instructables I can find that use an LM386 mention heat sinks. I think I'm going to get one or two LM386s tomorrow and see how they work.

 

The DIP version of the LM386 has a junction-to-ambient thermal resistance of 107 °C/W and a max junction temperature of 150 °C. If you are starting out at 25 °C then you can ask it to dissipate about 1.1 W without exceeding the max temperature.

 

Thank you. I was just about to ask why none of the Instructables I can find that use an LM386 mention heat sinks. I think I'm going to get one or two LM386s tomorrow and see how they work.

Have a look at this thread, especially post 4; I am still using this little amp in my old truck to listen to my MP3 player.