Ok , like i said before on other post i'm new at lumenlab...im sory my bad English but i'm from Argentina , i have always wanted to have a proyector to watch my movies since i was little, but unfortunately i dont have the money to buy one...So this pj seems Great to me, but now i dont have the money to buy the lcd monitor they are really expensivein Argentina...so if anyone wants to donate one i will be happy
I want to colaborate somehow whit this project but i cant do it, like i said before, the problem of the LCD
Anyway...i found this section in the forum dedicated to Audio and guess what...i think i could give a little of my help in this one!
I have been doing amps for my personal use in the past, experimented with some amps and i will post everything i can to help you with your sound system.
I'm not an electronic expert, only a hobbyst i have never study so my design or my method are open to discussion, anyway all of these seems to work fine for me.
All of these are easy to do amps and whit a very low budget.

So...lets starts...
First of all let me show you a picture of how should be made your sound system.This is only for one channel you will have to build 2 for stereo sound and 5 for 5.1.




The pre-amp.
My prefered pre-amp was the one i built with a 741 opamp, the 741 has been used in a lot of circuits for many years, i think that is one of the first opamps ever built...So after i made it i found it to be very stable and i didnt have any problem using it in my first stage of my amps. it can be replaced by a tl072 that seems
to be less noisy.
this are pictures of a single preamp i made two years ago and it still works perfectly.
Unfotunatly i dont have at hand the schematic and the part list but i promissed to post it later.
Here is a pic so you could see how easy it is made and that it has only a few components.






The Eq.

Ok...i dont have the eq plans yet ready...i promissed i will put it later too...and discuss about it another time.
So that leads to the next phase...


The Amp.

I will post the pdf of some opamps that i have used and that seems to work very fine.
first of all i will start with the TDA2040.
The TDA2040 is a 20W HI-FI amp it is my favorite, easy to make and a very good quality.
In the PDF you will find the circuit diagram and the pcb layout for make one.

http://rapidshare.com/files/30814604/1460.pdf.html

If you want less power you can use other TDA amps i think that they are named TDA2015, TDA2010 or something like that and if you want more power there is to a TDA2050 , search for this in google you will find a lot of information over it.
The good thing is that all the amps in this series seems to use the same PCB layout so if you mount the amp in a socket you can replace it later for other with more power , making your amp very versatile to modify it.


The next op amp is the TDA1554
This has worst sound , its intended for Car audio so his distorsion at a max level its greater,still...it worth the try, it has worst sound but is not too bad either. The good thing about it is that it has 4 x11W channels and it can be easy to set up, you can even duplicate the power of the channels making 2x22W chanels with a very easy change mod in the way that this is connected. So you can use one TDA1454 for the front and back speakers and a tda2040 for the subwoofer, we will try to have always the subwoofer with more power than the other 4 channels because the low frecuencies should always be reenforced.
Here you have the PDF


http://rapidshare.com/files/30814819/TDA1554_263233.pdf.html


The PDF dont have the pcb layout for it , i will post it later...but here you have some pics of one i built for experimenting purposes.




This could be a little incomplete but i will complete it later in future post ,its only a general idea of a tutorial that i hope that be fully documented. Again...this is open to discussion i'm only intended to give beginners a way to start in this subject.


I have never write a text so large in english so i think it would have lots of errors! Excuse me for that

I hope you find it useful and if you want to send me any lcd screen you will be my good


byeeeeeeeeee!

Sounds Great! i think i might build a 2channel system and make 2 of my monitor-speakers active and put in my kitchen, are these HI-Fi enough to compare itself to commercial amps in the same Wattage range? or do you get an uneven frequencyresponse and ground noise? What would 2 complete 2 channel amps cost ya think?

Lots of cool DIY audio schematics here : http://sound.westhost.com/projects.htm

Hi, sory the delay, i had some problems and i couldnt update the Thread...
Ronin, The quality of these is very Good, in fact the schematic oh the preamp using a 741 whas taken from a not so old SONY preamp.
Ground noise would not be a problem IF you take the right Choise when you are designing the case and the board.
About the cost here in Argentina you can find the parts for the 2 Channels amp with case and everything for about $50 i think...
If people is interested i can make some Boards Ready to use...just let me know...
These is a quick reply, i think that in the next week i will post a little more to complete these with more info...
Bye!

thanks for sharing this interesting thread. I really need Hifi Equipment with low cost and Good Quality sounds for the output.
i'd like to build for 2 channel, but i don't know schematic & PCB layout for EQ and PreAmp. could you post them?

Thanks

I would recommend project P3A from the sound.westhost website.

It's a 60-100 watt audio amp, class A/B, it sounds great!

I figure this is the best looking place to ask...
Power: Is a PC power supply high enough wattage for testing if the project amp is intended to go into a car?
Plan: Where should I begin? I have never built any electronics and would love to get into it. It seems a low watt, crap sounding amplifier would be a lot of fun but I would like to "upgrade" from there.

Thanks guys,
Dreis

A PC PSU can in theory provide the 12VDC for an intended car amp at adequate voltage, however, I personally find them to be a poor supply. Good enough for testing, but not at high loads.

Really though, you should look up the PSU's data sheet, and what it's current capabilities are for 12VDC, and what your amp's PSU can/will draw.