Hello everyone,
I'd like to build an audio speaker/amp but I don't know much about it and I'd like to know where to turn.

The purpose of this speaker would be to be both portable and pluggable on sector, to be used in student gatherings with my school.
My hope is that if it's plugged into the sector (220V), it can really send out the volume, for large outdoor gatherings.

I think there are quite a few different technologies in the audio world. Do you have at least any key words for what I should be looking at for my use case?

Thanks a lot

 

Modern manufacturing has rendered many formerly do-it-yourself projects unfeasible. You can buy a complete unit for a fraction of the cost of the parts. Never mind the fabrication and assembly costs. Your design experience is probably far from suitable to design a quality audio amplifier. My recommendation is to lower your expectations and start with a series of simpler and cheaper projects. After maybe 10 years you might have the resources to revisit this project.

 

Take a look at https://www.ebay.co.uk/itm/355841318153 for a very inexpensive D Type amplifier which might suit your needs? The operating voltage is from 8 to 24 VDC so you could power from a car battery if needed, or use a 19V 3A laptop charger when using the 220V mains supply. You can "recycle" old laptops, but never throw away the chargers!

For a cheap effective loudspeaker system look for speakers taken out of scrapped cars. They may not be Hi Fi but they are as good as most PA systems. You can series and parallel connect them together if they are not able to handle the amplifier power. Google "Sweet Sixteen Speakers" to get the idea.

You can also buy inexpensive pre-amp modules with a volume control, but if you are keen to build something yourself, this is where I would start. There are lots of example schematics available on the web.

 

Take a look at https://www.ebay.co.uk/itm/355841318153 for a very inexpensive D Type amplifier which might suit your needs? The operating voltage is from 8 to 24 VDC so you could power from a car battery if needed, or use a 19V 3A laptop charger when using the 220V mains supply. You can "recycle" old laptops, but never throw away the chargers!

For a cheap effective loudspeaker system look for speakers taken out of scrapped cars. They may not be Hi Fi but they are as good as most PA systems. You can series and parallel connect them together if they are not able to handle the amplifier power. Google "Sweet Sixteen Speakers" to get the idea.

You can also buy inexpensive pre-amp modules with a volume control, but if you are keen to build something yourself, this is where I would start. There are lots of example schematics available on the web.

small D-class amps like these were my original idea, but I was wondering if there was anything better.

 

I'd like to build an audio speaker/amp but I don't know much about it and I'd like to know where to turn.

You'd be better off just buying something.

 

it's so sad that as soon as we ask a question to learn, we're told to take something ready-made.
In electronics, in programming...

How can you learn if you can't start your own projects?
We're going to end up in a world where only Chinese factories will be producing, and nobody will know how to do anything.

I'm curious, I like to know how things work, please don't just say "use a library" or buy something.

it's deeply sad

 

it's so sad that as soon as we ask a question to learn, we're told to take something ready-made.
In electronics, in programming...

How can you learn if you can't start your own projects?
We're going to end up in a world where only Chinese factories will be producing, and nobody will know how to do anything.

I'm curious, I like to know how things work, please don't just say "use a library" or buy something.

it's deeply sad

The problem is that you've demonstrated no understanding of the subject matter. An audio amp isn't going to provide more, or less, power if it's powered from line voltage or a battery. You design the amp to provide a certain number of watts and it provides them regardless of the power source - assuming it gets sufficient power.

Make versus buy decision are a part of life. There are many things that I can design and build, but there are often commercial solutions that are good enough and cost less than it would cost to build one. I'm retired and have a lot of discretionary time, but I'm still not inclined to waste it on fruitless endeavors.

 

I agree that buying will be cheaper, and maybe that's how it will end, but that doesn't take away the fact that I want to really understand the thing, draw the circuit and why not make a simulation of it.

Concerning the battery, we misunderstood each other, indeed an amp is an amp, but connecting a 2x150W to a battery can be complicated... so I was thinking more of two more or less isolated circuits.

 

Hi Ethamin
I agree, a mains power supply would make more sense for a permanent installation, than battery powered.
With which simulator, are you familiar ?
E

 

Hi Ethamin
I agree, a mains power supply would make more sense for a permanent installation, than battery powered.
With which simulator, are you familiar ?
E

I tested several of them, but settled on NI Multisim.
But if you have something better, I'd be happy to consider it.

 

Dennis has made a valid point. You need to define your objectives in order to decide if you should build or buy.

You can buy a portable bluetooth power amp for a lot less than what it would cost to DIY.

You can buy a Class-D power amp module or an automotive power amplifier and build your own. I have done this. But you are not going to learn how to design and build a power audio amplifier.

If you want to build an audio amplifier from scratch there are many tutorials on this. There are also circuits and design ideas to follow on many websites. This is a long and steep learning curve if your knowledge of electronics is limited.

 

If you really want to roll you own, there here's one place to start with Class D audio amp ICs.

Doing it from scratch using all discrete components with your level of electronic knowledge is problematic at best.

 

If you wish to learn about the workings of a push-pull class-AB audio amplifier, you can follow this thread.

https://forum.allaboutcircuits.com/threads/designing-a-simple-audio-amplifier.152741/

However, it is going to fall far short of being a neighbourhood or dorm boombox.

 

From your initial post it seemed you were more interested in results than learning. I did suggest a helpful pathway to the learning you seek by starting with simpler circuits and concepts. As others have pointed out an audio amplifier sounds simple in concept but is enormously difficult to achieve when all of the picky details are considered.

There is an analogy to the audio amplifier in astronomy and telescope making. This involves the precise grinding of mirrors of ever-increasing size. The right way to do this is to start small, for example with a 2" mirror. That won't allow you to see far away galaxies but will suffice for the solar system. The apocryphal tale is that if you want to grind a 12-foot mirror you will get there faster by starting with a 2-inch mirror. The point is that in starting with the small mirror you will learn the patience and the techniques for grinding a 12-foot mirror.

It was not my intention to dissuade you from any endeavor you might want to undertake, but only to offer counsel on the best way to go about it. I'm sorry you missed that point.