Is it unreasonable to ask the chip makers to make an audio power amp that has everything built-in, that by default, takes direct input from MP3 players, amplifies with default internal gain of 20dB, takes AC power directly from a half or a full wave transformer and outputs to speakers without using any external component?
Default Gain of 20 dB can be changed from 1 dB to 30 dB just by changing the value of 1 external resistor.
Default Gain of 20 dB can be changed from 1 dB to 30 dB just by changing the value of 1 external resistor.
Its a jolly interesting question
The problem is the energy storage components - nobody has a clue how to fit a few thousand uF of capacitance and/or hundreds of uH of inductance onto a chip. So for the forseeable future, caps and coils will always be external.
Since you asked, yes there is.
Whenever you have to solder close to a heat-sensitive semiconductor device, on one of its leads or pins, you need to divert the heat away, before it reaches the device itself.
One simple way to do that is to put a rubber band around the handles of your long-nose pliers and clamp them onto the IC pin, BETWEEN where you are going to solder and the body of the IC.
-----------
I usually buy from mouser.com, but sometimes from Digikey or Allied. You should get their paper catalogs, too. They are excellent references, especially if you don't already know what all is available, or what every part might look like.
Last edited:
Think about what you are suggesting. You CAN do this yourself. Build an entire amp the traditional way using the usual power supply subcircuit, usual resistors and capacitors. Put it in an amp case with everything you need.
NOW, fill the entire interior of the amp case with epoxy - there you have it, a single "chip" that does what you want. Now you have it but the customer base is "1", nobody else necessarily wants it the exact same way you do so it will be prohibitively expensive to develop and manufacture... but we can negotiate a price if you want me to build you this "chip". Just kidding. They integrated the parts they needed to, in order to have a product that meets a specification. The other parts are not fixed, can vary and still meet the specification.
Last edited:
No name calling, just some descriptive text. I promise if you can persuade National, Motorola or anyone else (maybe a California start-up) to develop and sell such an item, I will be near the first in line to get one. I'm just old enough to remember how long it took and how much science had to be developed to go from my first 9 transistor radio (1952) to my current smart phone. I am not trashing your concept - Just trying to encourage you to give the engineers a little elbow room. 
Regards
Regards
Last edited:
Iphone is small enough and it delivers about 3 watts of audio. If you take all of the video, radios, memory and other electronics out and keep the audio part only, you will have the minimalistic chip.
Anyhow, the L4780 without the 4 caps is stable on the breadboard. So, I am going to build it on a PCB tonight.
Thank you very much for each and every comment.
You STILL do not understand? Another reason not to is we use electrolytic capacitors, but they can't be put on the same chip due to not being able to withstand the heat. They could develop solid polymer or other types with appropriate voltage and capacitance rating that would resist the heat but for the voltage and capacitance needed they would make it a VERY large and VERY expensive chip.
If it's that important to you, develop this tech yourself and sell it to National Semiconductor or whoever will bite. It's "about time" you develop it.
I guess some people have to learn the hard way.
Last edited:
I refuse to allow myself to be conned.
I may have read it on the internet, but it cannot be true.
I do understand that your vision is very different than mine. I have seen numerous audio chips take use DC blocking input caps that have less than 1 uf capacitance. Similarly, I have seen numerous chips with minimal or no output caps. We have the technology today to "print" these caps inside ICs.
About the L4780 amp, I will update this thread if the PCB version does not work.
Last edited:
I have an iPhone and does give up to 1.5 watts per channel (total 3 watts) when connected to external speakers. It is true.
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.
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.