Help Building L4780 Amp With Absolute Minimal Components

[AndrewT]

Are you suggesting there are a pair of these inside every Iphone?

[!]

Originally Posted by sellerr2d2

I meant 1 micro Farad (1 uf). I have also seen amp chips that use .01uf as input DC blocking caps. Technology exists today to print these caps inside the IC.

They do not include input coupling caps because not all applications need them. Same with output coupling caps. Further there are various grades & types which "some" people claim affect the sound, and some people will pick a cap value that makes a high pass filter for their application but others don't want that.

However I was referring to bulk capacitance on the power rails on the amp PCB, having the chip on a breadboard with no oscillations is not evidence it meets specifications at the power level you used nor higher power. Higher output requires more capacitance. You might choose to integrate the power supply circuit onto the amp PCB to serve as this capacitance yet that is another example of why not to put it in the chip, to keep cost down and controlled by the amp designer.

[sellerr2d2]

All I am saying is when I connect my iPhone headphone's output to my 400 watts flat response monitors/speakers without using any amplifier, they sound great. I read somewhere that iPhone has a built-in class D amplifier that delivers up to 1.5 watts of audio per channel. It even senses whether I have headphones or external speakers attached and automatically changes the output from 400 mw to 1.5 watts based on the impedance of the speakers and the length and connection bands of the male connector. Very smart.
Back to my L 4780 project.

[tuhkam]

No, just a suggesting a big "chip" that only needs power to operate.
The 4GS seems to use a Cirrus Logic chip, according to the reviews it does a good job in there.

[!]

Originally Posted by sellerr2d2

All I am saying is when I connect my iPhone headphone's output to my 400 watts flat response monitors/speakers without using any amplifier, they sound great. I read somewhere that iPhone has a built-in class D amplifier that delivers up to 1.5 watts of audio per channel. It even senses whether I have headphones or external speakers attached and automatically changes the output from 400 mw to 1.5 watts based on the impedance of the speakers and the length and connection bands of the male connector. Very smart.
Back to my L 4780 project.

A random amp doesn't need to be smart to do something similar. No sensing, ohm's law.

10V signal output into 32 ohm headphones = 0.31A = 310mW

10V signal output into 8 ohm speakers = 1.25A = 1.25W