Audio Amp vs Op-amp?

[Braeden Hamson]

Hey guys,

I'm working on a simple audio based light show for school. It has frequency dependant filters whose outputs power LEDs. The effect of this is to visualize the amplitude of certain frequencies in a song. As a part of this project I need to power a speaker. So I went to my schools shop and picked up a TDA2005

https://www.st.com/resource/en/datasheet/tda2005.pdf

20W is overkill, but aint no kill like overkill. I bought it because it said "audio" on it to be brutally honest. It's not like I know what I'm doing

My question is, whats the difference between this and a standard op-amp? Say LM741 or RC4558? The only thing I could find is that this bad boy can do 20W

Thanks!

 

[Audioguru]

The TDA2005 is a power amplifier to drive a low impedance speaker with plenty of current to make lots of loudness.
When the power amp produces lots of power in a speaker then the power amp gets hot so its case has a metal tab that can be bolted to a heatsink.
With an output power of 20W the distortion is horrible. It sounds good up to 15W.

An opamp has a low output current and if it drives a speaker the low current will make very low level sounds in a speaker. Its minimum load is 2k ohms but a speaker is much less at 4 ohms or 8 ohms. If an opamp is in a correct circuit then it will never get hot.

 

[Braeden Hamson]

That makes a ton of sense, thank you