LM386 versus Op Amp

[srobertjames]

What is the advantage of an LM386 over a regular Op Amp?

 

[QuietMan]

Mostly power out. An op amp is designed to go to frequencies above audio (even if it doesn't go extremely high frequencies), while a LM386 is a specialty part where it doesn't matter.

An op amp is much simpler to predict mathematically. A LM386 is meant to be a power audio amp, which it does relatively well. Nowadays there are better, but not cheaper or as common.

 

[transistor495]

Q. Do you think that LM386 comes under Op Amp category?

 

[audioguru]

An op amp is designed to go to frequencies above audio.

No.
Many older opamps cannot produce upper audio frequencies.
The LM324 and LM358 opamps have a max output that drops at about 2khz.
The 741 opamp has a max output that drops above 9kHz.
The TL07x opamps have a max output that drops above 100kHz.

 

[audioguru]

What is the advantage of an LM386 over a regular Op Amp?

An LM386 is a little POWER amplifier, not an opamp. Its max output current is about 350mA. The max output current from an opamp is about 30mA.

The LM386 power amplifier has built-in negative feedback and built-in biasing. Opamps don't.

 

[srobertjames]

The LM386 power amplifier... built-in biasing. Opamps don't.

If my signal is centered around 0V, and my LM386 is single supply 5V, do I have to manually rebias the incoming signal to 2.5V?

 

[audioguru]

The inputs of the LM386 are biased at 0VDC, not at half the supply voltage like opamps are. When the inputs are at 0VDC then the output is at half the supply voltage.